Nano Fluids Research Papers - Academia.edu (original) (raw)

2025, International Journal of Heat and Mass Transfer

An experimental study was conducted to examine the air flow behavior in the channel of a transpired air collector under different heating conditions. Velocity fields were measured using Particle Image Velocimetry (PIV). Mean velocities and turbulent properties were computed and evaluated. Results show that at high flow rates, the flow was dominated by forced convection while at the lowest flow rate the flow was primarily buoyancy driven, where buoyancy-induced stabilities and heating effects were strongest. It was observed that the buoyancy-induced instabilities enhanced the magnitude and modified the structure of mean and turbulent properties as compared to the unheated flow. The flow rate influenced the relative magnitudes of the normalized mean and turbulent velocities that were enhanced with a decrease in the flow rate at a given heating condition. Collector efficiencies up to 70% were observed, which could be attributed to the corrugation surface geometry that enhanced turbulence and provided a larger heat transfer surface area.

2025, Scientific reports

Water-based mud (WBM) faces challenges in high-temperature, high-pressure (HTHP) conditions due to fluid loss and property degradation. Enhancing eco-friendly drilling fluids with optimal rheology is crucial for sustainable, cost-effective, and environmentally safe drilling operations. This study formulated a WBM using green-synthesized zinc oxide (ZnO) nanoparticles (NPs, ~ 45 nm) and tragacanth gum (TG), a biodegradable natural polymer. The synthesized ZnO NPs were comprehensively characterized using energy-dispersive X-ray spectroscopy (EDS), field-emission scanning electron microscopy (FE-SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA/DTG) to determine their structural, morphological, and chemical properties. Rheological properties, including flow behavior index (n), consistency index (K), plastic viscosity (PV), and yield point (YP), were analyzed at 25, 50, and 75 °C using the Binghamplastic and Power-law models. The accuracy of the model was validated using Analysis of Variance (ANOVA), which assessed the significance of the results. Additionally, Design Expert software was utilized to optimize the concentrations of TG and ZnO for elevated temperature applications. Moreover, the response surface methodology (RSM) results were evaluated by reporting the R 2 and accuracy metrics, confirming the strong correlation between predicted and actual values, which demonstrates the model's robustness. Three optimal samples underwent HTHP filtration tests at 120 °C and 500 psi. The ideal formulation of 750 ppm TG and 0.25 wt% ZnO NPs improved PV by 27.84%, YP by 43.16%, reduced fluid loss by 54.16%, and mud cake thickness by 25%. The optimized sample showed superior performance, with a 'K' of 56.12 cp and a 'n' of 0.2272, ensuring effectiveness under HTHP conditions. This sustainable formulation reduced environmental contamination risks and drilling fluid consumption while enhancing operational efficiency.

2025, Semarak Ilmu Publishing

Scientists are striving to discover new methods to reduce energy consumption in response to the high demand for energy. The purpose of this article is to find how adding nanoparticles to the compressor oil can enhance the cooling of an air conditioner and to compare this oil to natural oil without nanoparticle addition. Nanomaterial’s were added to the compressor oil at a mass concentration of 0.2%. Nanoparticles (Al2O3) were prepared, and then the stability of the nanoparticles was evaluated through direct monitoring, and this monitoring was done over different time periods. The results obtained showed that conditioning leads to enhancement when adding nanoparticles to the base oil present in the system, by making a comparison with the use of oil alone. The results showed an increase in the cooling rate of the Nano-oil system by an increase estimated at (16%), while the increase in the efficiency of the Nano-oil system was higher than that, reaching (19%) in the case of comparison with the traditional system used in the system. Another result obtained is that when solid nanoparticles are added to the cooling oil in the system, this leads to an improvement

2025, Journal of emerging technologies and innovative research

One of the simplest and applicable heat exchangers is double pipe heat exchanger (DPHE). This kind of heat exchanger is widely used in chemical, food, oil and gas industries. Upon having a relatively small diameter, many precise researches have also hold firmly the belief that this type of heat exchanger is used in high-pressure applications. They are also of great importance where a wide range of temperature is needed. It is also well documented that this kind of heat exchanger makes a significant contribution to pasteurizing, reheating, preheating, digester heating and effluent heating processes. Many of small industries also use DPHEs due to their low cost of design and maintenance. The aim of present paper is to review "The various Nano fluids which affect the heat transfer rate with structural modification of double pipe heat exchanger." on the basis of previous study. Keywords; Heat exchanger, nano fluids, DPHE, heat transfer rate etc.

2025

Now a day's a geometrically modified Helical coil heat exchangers are widely using in industrial applications like cryogenic state processes, airconditioning, thermal nuclear reactors and waste heat recovery due to their compact size and high heat transfer coefficient. Advantage of using helical coils over straight tubes is that the residence time spread is reduced, allowing helical coils to be used to reduce axial dispersion in tubular reactors. In this study, numerical investigation of the influence of geometrical parameters such as tube diameter (d), coil radius(R), and coil pitch(p) on overall heat transfer coefficient in helical double tube heat exchangers are performed using a professional CFD software-FLUENT. In recent years, numerous styles were introduced for heat exchangers that apply to completely different applications; sadly, their heat transfer co-efficient wasn't reliable at different operational conditions. the standard of the heat changed rate wasn't optimized and there have been many deficiencies and errors in styles. The heat transfer of the copper material is enhanced in comparison with other material unfortunately thermal resistance is reduced with an increase in pressure drop thus enhancing the heat transfer on the heat exchanger. Helical architecture is often designed with a clear motive of compact size and also address heat transfer co-efficient and other ancillary attributes efficiently and effectively. So the better material is suggested for an industrial heat exchanger according to the applications is Copper with the basis of simulation results. The geometry and different dimension parameter of the helical coil show that the proposed study in different material properties and different mass flow rates to heat transfer are maximum in different parameter helical coil heat exchangers. Finally, the heat transfer increase for the copper material compared to another material but with the increase in pressure drop the corresponding thermal resistance decreases which allow the improved heat transfer rate and the rate increases from Aluminum to Bronze to Copper. With the drop in temperature, the thermal resistance is reduced which enhances the heat transfer rate. The simulation results show that the copper has a high heat transfer coefficient than Aluminum and Bronze while operating in identical conditions. Due to the extensive use of helical coils in various applications, knowledge about the flow patterns and heat transfer characteristics are important.

2025

The acoustical qualities of nanofluid molecules are affected by their liquid cohesive properties, which can differ significantly depending on the circumstances. The extracellular polymer xanthan gum is mostly produced by the bacteria Xanthomonas campestris. Its pseudoplastic properties and thermal stability have led to its typical addition to water-based drilling fluids. It is also widely utilized as a thickening and emulsion stabilizer in industrial applications. An innovative method for creating nanofluids is to use ultrasonic technology to convert biopolymer base fluids into nanoparticles. This study uses gelatin as the foundation fluid and various weight percentages to assess the density and ultrasonic velocity of synthesized nanoparticles. The aluminum oxide (Al 2 O 3) nanofluids are produced by the study team by ultrasonically transforming a precursor in aqueous xanthan gum. The XRD and FESEM methods are used to characterize the synthesized nanoparticles. After ultrasonication, the findings of ultrasonic velocity, density, and viscosity measurements are analyzed. The stability of nanofluids is investigated using a theoretical framework and experimental data. The outcomes of previous studies and ultrasonic spectroscopy bear striking similarities.

2025, The Journal of Chemical Physics

We conducted non-equilibrium molecular dynamics simulations to investigate Kapitza length at solid/liquid interfaces under the effects of bulk liquid pressures. Gold and silicon were utilized as hydrophilic and hydrophobic solid walls with different wetting surface behaviors, while the number of confined liquid water molecules was adjusted to obtain different pressures inside the channels. The interactions of solid/liquid couples were reparameterized accurately by measuring the water contact angle of solid substrates. In this paper, we present a thorough analysis of the structure, normal stress, and temperature distribution of liquid water to elucidate thermal energy transport across interfaces. Our results demonstrate excellent agreement between the pressures of liquid water in nano-channels and published thermodynamics data. The pressures measured as normal stress components were characterized using a long cut-off distance reinforced by a long-range van der Waals tail correction t...

2025

In this paper, the cooling tower (CT) performance has been experimentally investigated. Four types of packing with varying numbers of layers have been employed to investigate the impacts of packing density on the CT performance when using Copper Oxide (CuO) nanofluid as a working fluid. Three different concentrations (1, 3, and 5 %) of CuO+H 2 O nanofluid have been evaluated to assess the influence of nanoparticle concentration on the CT performance. The results show that adding more packing layers improves the thermal performance of the CT, regardless of the use of pure water or nanofluid. The effect is more pronounced when CuO+H 2 O nanofluid is employed. Furthermore, at a volume concentration of 5 % CuO+H 2 O nanofluid, the water temperature differential, cooling tower characteristic, and cooling efficiency increased by 15.3, 7, and 12.5 %, respectively, compared to pure water. However, the tower characteristic tends to increase for lower concentrations (3 %), but may decrease for higher concentrations (5 %). Nonetheless, the tower characteristic may ultimately increase for all concentration levels. Additionally, the impact of CuO+H 2 O nanofluid on temperature difference becomes more pronounced as the packing density increases. For example, the temperature differential of the water increases by around 7.5 % and 24.3 % for 7 and 20-layer packing, respectively. These findings suggest that utilizing CuO+H 2 O nanofluid as a circulating fluid in place of pure water can lead to improved thermal performance of CTs.

2025

This paper reports a numerical investigation the effect of inclination angle of the vertical face of a backward-facing step on the heat transfer performance utilizing Nanofluid for laminar flow. Al2O3 is the nanoparticle used in this investigation, and water is the base fluid. The finite volume technique is used to solve the momentum and energy equation in 2D backward facing step geometry with an expansion ration of 1.5. The effect of Re on Nu is investigated for the Reynolds numbers 40, 100 and 150 and for different volume fractions of the nanoparticles of 2%, 4% and 6% for all simulations. Nusselt number distribution at the bottom wall is computed. Pressure losses also reported for different Reynolds numbers and entropy is studied for a range of Reynolds numbers and for different volume fractions of Nanofluid. The results are validated with available literature. Four angles of inclination of the vertical step is investigated 90o,97.5o,105o and 115o. The effect of the inclination a...

2025, THERMAL SCIENCE

This study aims to develop a predictive model for the thermal conductivity of graphene nanoplatelets/SAE10W oil nanofluids using artificial neural networks (ANN) and response surface methodology (RSM). Generally, the property of thermal conductivity has been measured to enhance the heat transfer efficiency of traditional heat transfer fluids. Experiments were conducted using a thermal constants analyzer at different operating conditions, such as varying the volume concentrations of nanoparticles from 0.050% to 0.150% and increasing the temperature from 20 °C to 80 °C. Results showed an improvement in the thermal conductivity of the nanofluid, ranging from 19% to 41%. A single hidden layer with 12 neurons was found to be the most effective architecture for the ANN model. Additionally, a response surface was closely fitted to experimental data points in the RSM. Then, mean squared error, root mean square error, and R 2 values were employed to validate the accuracy of the predicted models. The correlation coefficients of the ANN and RSM models were 0.99761 and 0.9877, respectively. Also, the accuracy of the models was assessed in terms of margins of deviation. The margin of deviation for the ANN model ranged between +0.3926% and-0.4640%, whereas for the RSM model, it was between +0.4137% and-0.4166%. The comparison of the ANN model indicates greater accuracy than the RSM technique. This method for predicting the thermal conductivity of graphene nanoplatelets/SAE10W oil nanofluids is both cost-effective and inventive, minimizing experimental research durations.

2024

As related to straight tubes, helical tubes are more valuable because of its compact construction and it is being most broadly practiced in several heat transfer applications. Enrichment of heat transfer rate due to helical coil heat exchanger has been described by many scholars. The study of this investigation is the comparison between natural fluidand Nanofluid with the help of CFD on aluminium & copper tubes. The Titanium oxide (TiO2) and Zinc oxide (ZnO) is used as nanofluid and water as its base and also used water as a natural fluid. Helical coil was fabricated by bending 1000 mm length of aluminium & copper tube having 8 mm tube diameter and coil diameter is 35 mm and pitch 15mm. The comparison of pressure drop between water, TiO2 and ZnO fluid is found in this analysis. The result indicates that the ZnO have maximum pressure drop in aluminium tube as compared to other fluid and other tubes. Nano fluids have nano particles and the nano particles which have higher density will...

2024, Journal of emerging technologies and innovative research

2024, Development and Characterization of Advanced Nano-Coating with CeO₂, Al₂O₃, ZnO, and TiO₂ Nanoparticles for Enhanced Durability and Corrosion Resistance

This study introduces an innovative sol-gel nano-coating designed to address silica scaling and corrosion in hydrothermal and high-stimulation environments. By incorporating CeO₂, Al₂O₃, ZnO, and TiO₂ nanoparticles into a polymer matrix through precise sonication techniques, the coating achieves uniform dispersion and enhanced functional performance. The meticulous characterization of nanoparticle integration optimizes mechanical strength, thermal stability, and chemical resistance. Applied via a directional supplying device, the nano-coating is mechanically deposited onto the cemented walls of wells, providing robust protection against scaling and corrosion across diverse conditions, including varying temperatures and pH levels. Laboratory testing demonstrates significant reductions in silica scaling and corrosion rates, confirming the coating's efficacy in maintaining production efficiency in both hydrothermal projects and fracking operations. This paper details the synthesis process and molecular chemistry involved in nanoparticle integration, alongside the resultant structural properties of the coating. Thermogravimetric analysis (TGA) assesses thermal stability, while kinetic models such as Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) evaluate activation energy without assuming specific reaction models. The findings highlight the potential of this advanced nano-coating as a robust solution for enhancing operational longevity and efficiency in challenging industrial applications.

2024

In this paper, forced convective heat transfer in a water based nanofluid has experimentally beencompared to that of pure water in an automobile radiator. Five different concentrations of nanofluids inthe range of 0.1-1 vol.% have been prepared by the addition of TiO2 nanoparticles into the water. Thetest liquid flows through the radiator consisted of 34 vertical tubes with elliptical cross section and airmakes a cross flow inside the tube bank with constant speed. Liquid flow rate has been changed in therange of 90-120 l/min to have the fully turbulent regime. Results demonstrate that increasing the fluid circulating rate canimprove the heat transfer performance. Meanwhile, application of nanofluid with low concentrations can enhance heat transfer efficiency up to45% in comparison with pure water. Keywords— Nanofluid, Heat transfer coefficient, TiO2, Radiator, Cooling performance, Experimental

2024, eng

Nanofluids have gained significant attention as a promising solution to several challenges in drilling operations. Nanoparticles, due to their exclusive properties such as high specific surface area, strong adsorption potential, and excellent thermal conductivity, offer significant potential to improve the efficiency and performance of drilling processes. Regardless of the advancements in drilling fluids and techniques that have improved borehole stability, hole cleaning, and extreme operational condition (HTHP) management, limitations still persist. This review discusses a detailed summary of existing research on the application of nanofluids in drilling, exploring their types, properties, and specific uses in areas such as fluid loss control, wellbore stability, and thermal management. It also reports the challenges and future potential of nanotechnology in drilling, including nanoparticle stability, environmental considerations, and cost concerns. By synthesizing current research and highlighting gaps for further study, this review intends to guide researchers and industry professionals in effectively integrating nanofluid usage to optimize drilling practices and support a more sustainable energy future.

2024

Shell and tube heat exchangers are the most widely used heat exchangers in the process industries. Therefore, efforts have been directed towards a more efficient and cost-effective design and operation of these heat exchangers. Even small improvements may lead to significant saving in capital and operating costs. Consequently, extensive studies have been carried out in optimizing the design and operation of shell and tube heat exchangers. Nevertheless, existing studies only focus on heat exchangers operated with traditional heat transfer fluids such as water, ethylene glycol, oil and methanol. To date, optimal design and sensitivity analysis studies of heat exchangers operated with nanofluids are limited in literature. Nanofluids are emerging heat transfer fluids and lab-scale studies have reported that adding nano-size particles (less than 100nm) into the traditional heat transfer fluids is able to significantly enhance the heat transfer rate. This project, therefore, aims to carry out studies on optimal design and sensitivity analysis of a shell and tube heat exchanger operated with Al2O3 based nanofluids. The total annual cost (including capital investment and annual operating costs) was considered to be the main objective function in the process design to satisfy the operational constraints (pressure drop and velocity) and TEMA standards. Kern's method was adopted in the process optimization which was named automated Kern's method. To achieve the above aim, this study was conducted in different stages: heat exchanger model development and validation, optimal design studies of heat exchangers operated with traditional fluids, optimal design studies of heat exchangers operated with nanofluids and sensitivity analysis. Modelling shell-and-tube heat exchanger covers heat transfer and hydraulic modeling and these models were validated using experimental data from the literature. From the validation, it is evident that the predicted data from the proposed models were in good agreement with the experimental data with a percentage error of less than 10%. Therefore, the proposed models can be adopted in the next stages. In the first part of the second stage, optimal design studies used two benchmark case studies originally designed and presented by and Sinnott et al. (2005). Using the same operating conditions and deciding variables, current studies indicated the reduction of total cost can be achieved by 26% and 53%, respectively. Then, more variables were introduced as optimized variables, such as tube diameter, tube length, number of tube pass, baffle ii cut, type of pitch, head type and ratio of baffle spacing to shell for optimizations (multivariable heat exchanger design) for both cases. Optimal design studies involving more deciding variables resulted in further cost reductions to 38% and 55%, respectively, as compared to the original design. Hence, the studies involving nanofluid in the shell-and-tube heat exchanger design showed that the reduction of annual operating cost and total capital cost could be further achieved. The total annual capital cost was reduced to 40.97% and 55.77%, respectively, as compared to the original design for both case studies. These highlight the effect of nanofluid as a heat transfer fluid. The last stage of this study was to perform sensitivity analyses of heat exchanger operated with Al2O3 / water based nanofluid. These analyses were carried out by varying the two main operating conditions (mass flow rate and nanofluid concentration) and investigating the effects of those changes on the heat transfer rate, pressure drop and cost. These operating condition changes were set to be ±5% and 10% from the optimal conditions obtained from the optimal design studies. From the conducted sensitivity analysis, the outcome showed that an increase in nanofluids concentration gave a negative effect on the objective function (total capital cost) in both cases. The total cost was raised with about 2.7% and 3.6% when nanofluids concentration was increased from 0 to +10. This is due to increase annual operating cost which was increased by 21% and 36% for the two cases, respectively. Therefore, the efficiency and effectiveness of the present design will be of significant importance in this area of study. In view of all the examined cases presented by the proposed model, it was observed that a minimized annual total cost was obtained. Nevertheless, it is recommended further optimal design studies should be extended to include different types and sizes of nanoparticles as deciding variables.

2024, Journal of Nonlinear Analysis and Optimization

In this work, convective heat transfer flow over a stretching / shrinking vertical sheet is
studied in relation to hazardous reactions, concentrations, and temperatures using nanoparticles. The
objective is to use MATLAB software's Bvp4c approach to transform the control linear ordinary
differential equations (PDEs) into an ordinary differential equations (ODEs) set for statistical
analysis. It is required to examine the interactions between a number of factors, including the Lewis
number, other bioconvection-related limitations, the concentration-thermal-buoyancy connection, the
chemical change constants and Prandtl numerals, and the rate of return between microorganisms and
thermal buoyancy. The bioconvection flow profiles, temperature, concentration, and velocity
numerical data are shown.

2024

This paper focuses on the heterogeneity of hardness distribution in the AA2014-T6 billets upset under rigid dies. The solid cylinders of height 24 mm and diameter 24 mm were compressed to different levels of strains by employing soap, boric acid and vaseline as lubricants on the faces of the billets and the friction factor (m) obtained from the ring compression test for the lubricants was given as input to the finite element software to examine strain distribution inside the cylinders. The strain distribution in the solid cylinders were correlated with the hardness distribution (VHN) and an equation was proposed to obtain the hardness of the billet. The Hill-Vonmises anisotropy factor was introduced to study the effect of anisotropy on the hardness of the deformed billet. The equation correlating the anisotropy and hardness was utilized to study the effect of anisotropy and the material parameter (C 1) on the hardness of the billet.

2024, International Journal of Trend in Scientific Research and Development

The paper proposes an experimental and numerical approach of analyzing on the influence of working fluid and mass flow rate on the heat transfer characteristic in plate heat exchanger by performing the experiment on an industrial counter flow plate heat exchanger with 59˚ chevron angle. In this study, numerical results obtained from Aspen HYSYS V10 Exchanger Design and Rating (EDR) were compared with experimental data and showed good arrangement. The effective heat transfer area is 4.2 m 2. Water is used as cold fluid and oil is used as hot fluid with the counter flow arrangement. Cold water flow rate is controlled at different flow rate of 2 m 3 /hr, 4 m 3 /hr and 6 m 3 /hr. Hot oil flow rate is varied from 3.6 m 3 /hr to 5.2 m 3 /hr. The inlet temperature of cold water and hot oil to heat exchanger were kept constant at 50˚C and 32˚C respectively. The experimental and numerical results show significant effect of flow rate on heat transfer rate, overall heat transfer coefficient, and effectiveness. It is shown that the Aspen HYSYS V10 EDR is a reliable tool for investigation of heat transfer characteristic in the plate heat exchangers at various flow rate.

2024, International Journal of Trend in Scientific Research and Development

The paper proposes an experimental and numerical approach of analyzing on the influence of working fluid and mass flow rate on the heat transfer characteristic in plate heat exchanger by performing the experiment on an industrial counter flow plate heat exchanger with 59 ̊ chevron angle. In this study, numerical results obtained from Aspen HYSYS V10 Exchanger Design and Rating (EDR) were compared with experimental data and showed good arrangement. The effective heat transfer area is 4.2 m2. Water is used as cold fluid and oil is used as hot fluid with the counter flow arrangement. Cold water flow rate is controlled at different flow rate of 2 m3/hr, 4 m3/hr and 6 m3/hr. Hot oil flow rate is varied from 3.6 m3/hr to 5.2 m3/hr. The inlet temperature of cold water and hot oil to heat exchanger were kept constant at 50 ̊C and 32 ̊C respectively. The experimental and numerical results show significant effect of flow rate on heat transfer rate, overall heat transfer coefficient, and effec...

2024, Journal of Applied and Computational Sciences in Mechanics

In this study, the numerical analysis was studied about mixed convection of sodium alginate (non Newtonian Pseudoplastic fluid) with Nano particle in a two dimensional rectangular channel containing several blocks. The temperature of inlet fluid to the rectangular channel were kept in steady state and fixed temperature that is less than wall temperature. To solve the Continuity, momentum and energy equations, numerical analysis and finite volume method with SIMPLE technique is used. In this study the effect of height and numbers of blocks, volume fraction of nano particle, Richardson number and Reynolds number is investigated on Nusselt number and skin friction coefficient. The results show that increasing of aluminum solid particles in sodium alginate will increase the heat transfer rate and skin friction coefficient in channel length. Also by increasing Reynolds number there is an increase in convection rate through the channel. In addition to the conclusions, increasing the block height from H/3 to H/2 enhance the average Nusselt number by 10% and skin friction coefficient by 13%. It is observed that increasing of Richardson number decreases the Nusselt number and skin friction coefficient. Also changing block number from 3 to 5 decrease Nusselt number about 3.5%.

2024, 4TH INTERNATIONAL BLACK SEA MODERN SCIENTIFIC RESEARCH CONGRESS

A numerical study was conducted for the thermal-hydraulic performance of double tube with outer twisted tube for three twist ratios with water as working fluid, where the outer wall was thermally isolated. The investigation and discussion focused on the Reynold numbers (5000-30000), twist ratio (5,10,15), and the twisted of outer tube on the thermal and hydrodynamic properties of fluid. At lower twist ratio, strong presence of secondary flow impacts the thermal behavior model. Besides, it was observed that increase the effect of effectiveness of heat exchanger and overall performance was due to the increase in the swirling flow the development in blending and disturbance intensity allows heat transfer to increase.

2024, 6th ASIA PACIFIC International Modern Sciences Congress

Heat transfer and Turbulent flow characteristics of fluid flow inside in the double elliptical twisted tube heat exchanger with different volume concentrations of nano fluid were investigated numerically. The investigation has been conducted for Reynolds number range from 5000 to 30000 while the twist ratio (Tr=5). Four values of nano fluid volume concentration is examined as (φ=0.05, 1, 2.5, 4) %.The research is aim to promote the heat transfer enhancement by means of the combined mechanism of the double elliptical twisted tube heat exchanger and nano fluid. The obtained results show that the the twisted elliptical tube improvement the heat transfer performance compared with plain tube. This increase is improved as the volume concentration of nano fluid increases. The twisted elliptical tube can reduce the dissipation based thermal resistance that provides the great benefit in heat transfer. In addition, the numerical consequence revealed that, the effectiveness of the heat exchanger and the overall performance factor increase as twist ratio decreases. The twist pitch has an influence on the overall thermal hydraulic performances. The twisted elliptical tube with φ=4% and Tr=5 has the best overall thermal-hydraulic performance. The twist elliptical tube bring on the pressure drop because of the twisted wall the pressure drop both increase with increasing Reynolds number.

2024, International Journal of Mechanical Engineering

The turbulent flow and thermal characteristics with (Al2O3-Water) nano fluid in the double circular twisted tube heat exchanger was studied numerically. The prime objective of this study is to improve the performance of the double circular tube heat exchanger by utilizing the hybrid approach of twisting tube and nanofluids. Nanoparticles of (Al2O3) are used with pure water as base fluid. The volume concentrations of nanoparticles studied were (0.05, 1, 2.5, 4) % and Reynold number ranging (5000-30000) for a twist ratio (Tr=5). The continuity, Navier-Stocks and energy equations with k-ϵ model were used to model the flow and thermal field. Ansys fluent 18.2 was adopted for solving these equations. The consequences exposed that the heat transfer rate is directly proportional to with increased the volume concentration of nano fluid and decreasing the twisted ratio (Tr). This means that the heat exchanger performs better with a lower twist ratio. In addition, the effectiveness of the heat exchanger is improved when using the nano fluid as 6%, as it reaches the highest value at the Re number of 30000 and volume concentrations at 4%. In addition, the pressure loss increases with increasing Re number and nano fluid volume concentration.

2024

Heat exchanger is used in different industries to heat transfer enhancement purpose. This paper studies the different heat transfer enhancement technique, to find out the some new technique for enhancement of heat transfer rate.

2024

Kekerasan dalam rumah tangga merupakan suatu permasalahan dalam keluarga. Kekerasan Dalam Rumah Tangga (KDRT) bisa menimpa siapa saja termasuk, suami, istri, dan anak. Dalam penelitian ini hanya akan membahas secara umum mengenai Kekerasan Dalam Rumah Tangga (KDRT) yang dipersempit mengenai penganiayaan oleh suami terhadap istri. Hal ini bisa dimengerti karena kebanyakan korban dalam Kekerasan Dalam Rumah Tangga (KDRT) adalah istri. Bila kita lihat lebih jauh banyak sekali keluarga yang tidak bahagia, rumah tangga yang selalu ditiup oleh badai pertengkaran dan percekcokan. Dengan keadaan yang semacam ini istri manapun tidak akan nyaman dalam menjalani kehidupannya. Dalam Undang-undang RI No.23 Tahun 2004 mengenai Kekerasan Dalam Rumah Tangga (KDRT) yang kebanyakan adalah perempuan, harus mendapat perlindungan dari negara dan/atau masyarakat agar terhindar dan terbebas dari kekerasan atau ancaman kekerasan, penyiksaan, atau perlakuan yang merendahkan derajat dan martabat kemanusian. Suami yang seharusnya berfungsi sebagai pengayom justru berbuat yang jauh dari harapan anggota keluarganya. Dalam KDRT (Kekerasan Dalam Rumah Tangga) mendapat tanggapan yang serius dari berbagai organisasi perempuan baik yang berhubungan dengan pemerintah maupun nonpemerintah hingga lahirnya UU No. 23 Tahun 2004 tentang Penghapusan Kekerasan Dalam Rumah Tangga. Kekerasan Dalam Rumah Tangga khususnya penganiayaan terhadap istri, merupakan salah satu penyebab kekacauan dalam masyarakat. Berbagai penemuan penelitian masyarakat bahwa penganiayaan istri tidak berhenti pada penderitaan seorang istri atau anaknya saja, rentetan penderitaan itu akan menular ke luar lingkup rumah tangga dan selanjutnya mewarnai kehidupan masyarakat kita. Menurut Undang-Undang RI Nomor 23 Tahun 2004 tentang Penghapusan Kekerasan Dalam Rumah Tangga (PKDRT), Kekerasan Dalam Rumah Tangga adalah setiap perbuatan terhadap seseorang terutama perempuan yang berakibat timbulnya kesengsaraan atau penderitaan secara fisik, seksual, psikologi, atau penelantaran rumah tangga termasuk juga hal-hal yang mengakibatkan ketakutan, hilangnya rasa percaya diri, hilangnya kemampuan untuk bertindak, rasa tidak percaya, atau penderitaan psikis berat pada seseorang. Undang-undang ini juga tidak bertujuan untuk mendorong perceraian, sebagaimana sering dituduhkan orang. Undang-undang Penghapusan Kekerasan Dalam Rumah Tangga ini justru bertujuan untuk memelihara keutuhan rumah tangga yang (benar-benar) harmonis dan sejahtera dengan mencegah segala bentuk kekerasan sekaligus melindungi korban dan menindak pelaku kekerasan dalam rumah tangga. Kekerasan Dalam Rumah Tangga bukanlah persoalan domestik (privat) yang tidak boleh diketahui orang lain. KDRT merupakan pelanggaran hak asasi manusia dan kejahatan terhadap martabat kemanusiaan serta bentuk diskriminasi yang harus dihapuskan. Undang-Undang ini merupakan jaminan yang diberikan negara untuk mencegah terjadinya kekerasan dalam rumah tangga, menindak pelaku Kekerasan Dalam Rumah Tangga (KDRT), dan melindungi korban Kekerasan Dalam Rumah Tangga (KDRT). Secara garis besar faktor-faktor yang menjadikan kekerasan dalam rumah tangga dapat dirumuskan menjadi dua, yakni faktor eksternal dan faktor internal. Salah satu indikasi permasalahan sosial yang berdampak negatif pada keluarga adalah kekerasan yang terjadi dalam lembaga keluarga, hampir semua bentuk kekerasan dalam keluarga oleh laki-laki misalnya pemukulan terhadap istri, pemerkosaan dalam

2024

Polymerase Chain Reaction (PCR) is widely used in biological research labs in order to detect hereditary diseases, diagnose infectious diseases, clone genes and other purposes. This work focuses on combining CFD and response surface modelling to explore the dependence of DNA amplification on two design parameters in a single phase, continuous flow PCR microfluidic device, consisting of a serpentine-like rectangular channel with three copper wire heaters. The spacing and the width of the microchannel between the heaters are selected as the two design parameters investigated. COMSOL Multiphysics ® 5.4 is used to simulate the performance and function of the microfluidic channel, while Design of Experiments and a polyharmonic spline are used to produce the response surface. The results indicate a ∼1.4% increase at the value of [DNA] in one PCR cycle.

2024, Proceedings of the 6th World Congress on Momentum, Heat and Mass Transfer

2024, International Journal for Research in Applied Science and Engineering Technology

The present work investigates the effect of pulsation on the transport process in a 2D microchannel. The inlet velocity varies sinusoidally in time at a constant dimension less frequency (St=10) and amplitude of 0.8. The working fluid is considered as water which is made to flow in the flow disturbing microchannel whiles the microchannel walls were kept at a uniform temperature. The solution of two-dimensional Navier-Stokes equation was performed using the SIMPLE algorithm with the momentum interpolation technique. The simulations were performed in the laminar regime within the Reynolds number range between 100-500 for the microchannel. The results of pulsating flow simulations had been analysed and compared with nonpulsating flow simulations. It is observed that the effect of pulsation in flow interrupting ribbed microchannel is significant and more enhancement of heat transfer is observed at higher Reynolds number while keeping the friction factor within tolerable limits.

2024, International Journal of Thermal Sciences

This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/copyright Author's personal copy An empirical study on the pressure drop characteristics of nanofluid flow inside helically coiled tubes

2024, Modelling and Simulation in Engineering

Reducing the wind loading of photovoltaic structures is crucial for their structural stability. In this study, two solar panel arrayed sets were numerically tested for load reduction purposes. All panel surface areas of the arrayed set are exposed to the wind similarly. The first set was comprised of conventional panels. The second one was fitted with square holes located right at the gravity center of each panel. Wind flow analysis on standalone arrayed set of panels at fixed inclination was carried out to calculate the wind loads at various flow velocities and directions. The panels which included holes reduced the velocity in the downwind flow region and extended the low velocity flow region when compared to the nonhole panels. The loading reduction, in the arrayed set of panels with holes ranged from 0.8% to 12.53%. The maximum load reduction occurred at 6.0 m/s upwind velocity and 120.0° approach angle. At 30.00 approach angle, wind load increased but marginally. Current resear...

2024, International Journal for Research in Applied Science and Engineering Technology

This paper contains waterless cleaning system method for solar panels. The solar panel system available for studying this work is inclined from top to bottom which provide a degree of slope to solar panels. The cleaning mechanism is placed on the main support frame to clean the surface of the solar panels which move upwards and downwards according to width of the solar panel and main frame. This operation is controlled by a control unit for the cleaning system of solar panels. The cleaning system removes the dust, dirt, sand and mass from the solar panel surface which results in improving efficiency.

2024, International Journal of Trend in Scientific Research and Development

In this paper, the heat transfer of fin without and with various extensions such as rectangular extensions, triangular extensions and trapezium extension is analyzed by changing its material (such as Aluminium alloy, Copper alloy and Structural steel), and then a comparison is made between them. After comparison near about 12% more heat transfer is observed in the fin with various extensions in compare to fin without extensions for all the material. Here maximum heat transfer is obtained for the fin with rectangular extension for each material and the material for which heat transfer is maximum is copper. So after overall comparison it is found that that Copper alloy with rectangular extension gives the maximum heat transfer. Here copper alloy fin with rectangular extensions gives higher effectiveness compare to other extensions of fin. I.

2024, International Journal for Research in Applied Science and Engineering Technology

Heat exchangers are very much essential industrial as well as domestic equipment usedeveryday. The fundamental basis for this statistic is shell and tube technology is a cost effective, proven solution for a wide variety of heat transfer requirements. There are various limitations with technology which include inefficient usage of shell side pressure drop, dead or low flow zones around the baffles where fouling and corrosion can occur, and flow induced tube vibration, which can ultimately result in equipment failure. This paper presents a recent innovation and development of a latest heat exchanger technology, known as Twisted Tube Technology, which has been able to overcome the limitations of conventional technology. This technology provides solution to almost all mentioned problems and provide good overall heat transfer coefficients through tube side enhancements. This paper primarily focuses on thermal analysis on twisted tube Heat exchangers.

2024, International Journal for Research in Applied Science and Engineering Technology

A heat exchanger is a piece of equipment designed to transfer heat from one medium to another efficiently. It relies on the conduction, convection, and radiation principles with fluids flowing against one another. There are many other forms of heat exchange, but we choose the double pipe heat exchanger since it has two pipes (outer pipe with cold fluid and inner pipe with hot fluid). The goal is to maximize the rate of heat transfer while monitoring the mass flow rates of the two fluids. In order to achieve this, we placed washers between the outer and inner pipes at a certain distance, which would lower the speed of the cold fluid and increase the efficiency of the heat transfer rate. They are extensively utilized in power plants, chemical and petrochemical facilities, oil refineries, sewage treatment facilities, air conditioning, refrigeration, and space heating systems. A heat exchanger is most commonly seen in internal combustion engines, where engine coolant circulates through radiator coils as air passes by, cooling the coolant and heating the incoming air.

2024, International Journal of Trend in Scientific Research and Development

Cooling towers make use of evaporation whereby some of the water is evaporated into a moving air stream and subsequently discharged into the atmosphere which results in cooling of the remainder water. The current research reviews various studies conducted on cooling tower using experimental and numerical techniques. Different design configuration and operating conditions on cooling towers are evaluated by various researchers. Significant findings from researches have shown new and improved design of cooling tower with much better performance as compared to conventional design.

2024

Penelitian bertujuan menganalisis dan memahami penegakan hukum terhadap kekerasan dalam rumah tangga di Kota Makassar dan faktor-faktor yang mempengaruhinya. Tipe penelitian ini termasuk dalam tipe penelitian empiris, dengan pendekatan keadilan dan kepastian hukum menganalisis fenomena sosial dari sudut pandang keadilan restoratif. Hasil penelitian bahwa Penegakan hukum terhadap kekerasan dalam rumah tangga kurang efektif disebabkan karena adanya faktor yang mempengaruhi sebagaimana pada kesimpulan kedua. Faktor-faktor yang mempengaruhi penegakan hukum terhadap kekerasan dalam rumah tangga adalah faktor substansi hukum, faktor struktur hukum dan faktor budaya hukum. This study aims to analyze and understand law enforcement against domestic violence in Makassar City and the factors that influence it. This type of research is included in the type of empirical research, with the justice approach and legal certainty analyzing social phenomena from the viewpoint of restorative justice. T...

2024, World Journal of Engineering and Technology

Nanolubricant mixing the normal lubricant with nanoparticles, gradually becomes a new trend study for metal cutting enhancement. An addition of the nanoparticles improves lubricating properties and convective heat transfer coefficient (cooling properties) of nanolubricants. In the present work, nanolubricant is formulated by using dispersions of 0.3% Al 2 O 3 nanoparticles in normal industrial oil VG46 for enhancement of gear machining performance of SCM420 steel. Comparative study of flank wear, crater wear and gear profile error in gear hobbing with normal oils in the existing production line as well as nanolubricant is studied. This study clearly reveals that tool wear, and gear profile error are reduced by the use of nanolubricant compared to that of normal oils. The paper results not only contribute the deeper understanding of the novel performance of nanoparticles in conventional cutting fluids, but also show a very promising solution to achieve the engineering economy effectiveness in gear machining.

2024, Nanomaterials

In the present study, the effects of using a corrugated porous layer on the forced convection of a hybrid nanofluid flow over a 3D backward facing step are analyzed under the coupled effects of magnetic field and surface rotation. The thermal analysis is conducted for different values of the Reynolds number (Re between 100 and 500), the rotational Reynolds number (Rew between 0 and 2000), the Hartmann number (Ha between 0 and 15), the permeability of the porous layer (the Darcy number, Da between 10−5 and 10−2) and the amplitude (ax between 0.01 ap and 0.7 ap) and wave number (N between 1 and 16) of the porous layer corrugation. When rotations are activated, the average Nusselt number (Nu) and pressure coefficient values rise, while the increment of the latter is less. The increment in the average Nu is higher for the case with a higher permeability of the layer. When the corrugation amplitude and wave number are increased, favorable impacts of the average Nu are observed, but at th...

2024, Fluid Phase Equilibria

Estimation and knowledge of transport properties of fluids are essential for heat and mass flow. Viscosity is one of the important properties which are affected by temperature and pressure. In the present work, based on the use of econometric and statistical techniques for parametric and non-parametric regression analysis and statistical correlation tests, we propose an equation modeling the relationship between the two parameters of viscosity Arrhenius-type equation, such as the Arrhenius energy (E a) or the pre-exponential factor (A s). In addition, we introduce a third interesting parameter called Arrhenius temperature (T A), to enrich the discussion. Empirical validation using 48 data set of pure solvents from the literature and studied at different temperature ranges gives excellent statistical results which allow us to redefine the Arrhenius equation using a single parameter instead of two ones. In addition, the proposed model is very useful for engineering data and permits to estimate one non-available parameter when the second one is available. 2014 Elsevier B.V. All rights reserved.

2024, International Journal for Research in Applied Science and Engineering Technology

This Experimental investigation was conducted to understand heat transfer characteristic of the pulsating heat exchanger, and the pulsating heat pipe is made of the copper tube, the copper tube internal diameter is the mm 5 mm and the outer diameter is 6.15 mm and the total turn of copper tube is the 5 turn. And this experiment performing at different filling ratio like 50% ,30%.and also change the working substance like methanol and acetone at the same heat input. The experimental result indicate that the total heat resistance of PHP is increased with the filling ratio and heat transfer rate achieves optimum in the working substance acetone at the 30% filling ratio. in the working substance methanol and acetone are used because of the both working fluid the boiling temperature less then the water, methanol boiling temperature was 64 ˚C and the acetone boiling temperature was 56 ˚C. By performing the our experiment we can say that the acetone as the working fluid is more efficient then the methanol at the 50% and 30% filling Ratio. In the acetone the 30% filling Ratio is more efficient.

2024, Gorontalo Law Review

Penelitian ini bertujuan untuk menganalisis kebijakan pemerintah Kabupaten Bone dalam menanggulangi kejahatan cyber sex yang terjadi di Kota Watampone, serta untuk menganalisis upaya pihak kepolisian dalam menanggulangi kasus kejahatan cyber sex yang terjadi di Kota Watampone. Metode penelitian hukum empiris merupakan suatu metode penelitian hukum yang berfungsi untuk dapat melihat hukum dalam artian nyata serta meneliti bagaimana bekerjanya hukum di lingkungan masyarakat. Hasil penelitian menunjukkan bahwa (1) Kebijakan Pemerintah Kota Watampone dalam menanggulangi kejahatan cyber sex pada Dinas Pemberdayaan Perempuan dan Anak (P2TP2A) menyediakan konsultasi hukum pada unit konsultan hukum P2TP2A untuk membantu korban dalam mendapatkan informasi mengenai posisi hukum atas kasus yang dialami korban atau informasi lain yang memperkuat pengetahuan atau pemahaman hukum korban dalam membuat keputusan (2) Upaya penegakan hukum yang dilakukan pada Polres Bone sudah benar adanya dengan me...

2024

The purpose of this study is; (1) To find out and analyze the efforts of the police in tackling the crime of violence in the household in the area of the Police Police in Mandai. (2) To find out and analyze the Obstacles faced by police investigators in the effort to overcome the crime of violence in the household in the area of Mandai Police. The research used is empirical legal research, which is a legal research method that functions to see the law in the real sense and examine how law works in the community. The study was conducted in the jurisdiction of the Mandai Police Station Maros Police, and the focus of the study was twofold: Preventive and Repressive: the results of the s tudy showed that prevention efforts were carried out preventively and repressively. While the obstacles faced in protecting women victims of domestic violence are the absence of implementing regulations related to protection orders, limited funds and the release of visum et repertum results require a lo...

2024

The climate behaviour suffers important changes as result of the impact with a rapid extension of the anthropic space. The abrupt modification of season temperature and severe wind storms are put in evidence now all over the world. Simulation of the dynamic effects of wind action upon the built environment in laboratory is a process of scaling at reduced dimensions of a complex combination of factors insuring similarity between the natural phenomenon and the one artificially reproduced. Usually, the design wind dynamic action on structures is identified with the so-called extra-tropical depressions, specific for middle global latitudes; the atmosphere is considered neutrally stratified, the vertical profile is in equilibrium with the terrain roughness in A.B.L. The simulations of wind speeds and pressures in the boundary layer of the air moving at the surface of the earth are based on vertical profile of the mean speeds, turbulence intensity, spectral power and histograms of the rec...

2024

The main purpose of this study is to survey numerically comparison of twophase and single phase of heat transfer and flow field of copper-water nanofluid in a wavy channel. The computational fluid dynamics (CFD) prediction is used for heat transfer and flow prediction of the single phase and three different two-phase models (mixture, volume of fluid (VOF), and Eulerian). The heat transfer coefficient, temperature, and velocity distributions are investigated. The results show that the differences between the temperature field in the single phase and two-phase models are greater than those in the hydrodynamic field. Also, it is found that the heat transfer coefficient predicted by the single phase model is enhanced by increasing the volume fraction of nanoparticles for all Reynolds numbers; while for the two-phase models, when the Reynolds number is low, increasing the volume fraction of nanoparticles will enhance the heat transfer coefficient in the front and the middle of the wavy channel, but gradually decrease along the wavy channel.

2024, Tikrit Journal of Engineering Sciences

Predictions are reported for mixed convection using various types of nanofluids over forward-facing double steps in a duct. The continuity, momentum and energy equations are discretized and the simple algorithm is applied to link the pressure and flow fields inside the domain. Different types of nanoparticles Al2O3, CuO, SiO2 and ZnO, with different volume fractions in range of 1-4% and different nanoparticles diameter in the range of 20-80nm in base fluid (water) were used. Numerical investigations are conducted using finite volume method. In this study, different parameters such as the geometrical specifications (different steps heights in the range of h1= 0.01m-0.04m and h2 = 0.03m-0.06m for FFS) are used. Different Reynolds numbers in the range of 50-2000 (laminar flow) are investigated to identify their effects on the heat transfer and fluid characteristics. The results indicate that SiO2-water has the highest Nusselt number followed by-water,-water and ZnO-water. The Nusselt number increases as the volume fraction increases but it decreases as the nanoparticles diameter increases. The velocity magnitude increases as the density of nanofluids decreases. The recirculation region and the Nusselt number increase as the step height, Reynolds number, and the volume fraction increase.

2023, International Journal for Research in Applied Science & Engineering Technology (IJRASET)

2023, The Bulletin of the Polytechnic Institute of Jassy, Construction. Architecture Section

Wind actions determines the most important load in the design of the support systems of the solar panels, wherever they are located-on flat or pitched roofs or at the ground level. The goal of simulations of the interaction between wind and the solar panels by Computational Fluid Dynamics (CFD) is to estimate the complex wind flow and pressures that act upon their surface. In the study presented herein, the wind pressure acting on 12 solar panels is simulated. The solar panels are placed in a regular array, mounted at ground level and tilted at 30º. Five wind directions (0º, 30º, 45º, 135º, 180º) have been analyzed with the computer code ANSYS 12 CFX.