Thermal Engineering Research Papers - Academia.edu (original) (raw)

A heat exchanger is a system used to transfer heat between two or more fluids or is a device which transfers heat from one medium to another. Heat Exchangers are used in both cooling and heating processes. The fluid may be separated by a solid wall to prevent mixing in both counter flow and parallel flow heat exchangers. The objective of this simulation is, To model a sheel and tube Counter Flow Heat Exchanger by using Solid work Premium 2016, To model Parallel Flow Heat Exchangers by using Solid work Premium 2016, To perform CFD analysis of both type heat exchangers by using Solid work 2016 Flow simulation, To find the temperature of Outlet hot water and outlet cold water in both Heat Exchangers and Finally to find the LMTD of both Heat Exchangers from the simulation.

- by
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- Thermal Engineering

The flat interface between two fluids in a vertically vibrating vessel may be parametrically excited, leading to the generation of standing waves. The equations constituting the stability problem for the interface of two viscous fluids subjected to sinusoidal forcing are derived and a Floquet analysis is presented. The hydrodynamic system in the presence of viscosity cannot be reduced to a system of Mathieu equations with linear damping. For a given driving frequency, the instability occurs only for certain combinations of the wavelength and driving amplitude, leading to tongue-like stability zones. The viscosity has a qualitative effect on the wavelength at onset: at small viscosities, the wavelcngth decreases with increasing viscosity, while it increases for higher viscosities. The stability threshold is in good agreement with experimental results. Based on the analysis, a method for the measurement of the interfacial tension, and the sum of densities and dynamic viscosities of two phases of a fluid near the liquid-vapour critical point is proposed.

- by Krishna Kumar
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- Engineering, Mechanical Engineering, Thermal Engineering, Condensed Matter Physics

Countercurrent gas±liquid¯ow in narrow rectangular channels simulated by plain and perforated ®ns is studied. Dierent¯ow patterns dependent on¯ow rates are observed and visualised in the channels. Flooding velocities and pressure drops are measured. Results are compared with previous experimental data obtained in rectangular channels. The present results focus on two particular types of¯ooding phenomena: that occurring at the column base and linked to plugging and that at the top, linked to reentrainment. A further set of experiments using perforated ®ns surprisingly shows a greater tendency to¯ooding of the perforated ®ns. However, there are marked dierences for the two types of ®ns and an explanation may be the two distinct¯ooding occurrences. Ó

- by André Bontemps
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- Thermal Engineering

In today's essential commodities, air conditioning system is one of the major energy consuming elements. Nowadays evaporative cooling systems are mostly preferred as an alternative to compressor-based air conditioned systems. It is reported that evaporative cooling systems consume 60-70 % less energy compared to compressor-based air conditioning systems. In this paper, performance analysis of a mist evaporative cooler is carried out experimentally. The performance parameters such as, drop in temperature, cooling capacity, saturation efficiency, the coefficient of performance are evaluated with respect to various ambient conditions and with a varied mass flow rate of air. Experimental data used to develop an empirical correlation to predict the temperature of cooled air by linear regression analysis. Predicted temperature of cooled air temperature by empirical correlation is validated through experimentation, and are good in agreement with experimental values.

- by Avinash Deshmukh
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- Thermal Engineering, Environmental Science

Industrial control systems are nowadays exposed in environments with rapid and unstable parameter changes and uses measuring equipments with critical output sensitivity. In the case of thermal gas analyzer, measurement errors are contributed by temperature, gas flow, and pressure. Error compensation is a key problem for these control systems. In recent years, it has been proven in the literature that artificial neural network (ANN) is a reliable and low cost solution to manage errors. Among all the algorithms of ANN, the back propagation is commonly used because of its simplicity and learning methodology is easy to realize. However, it has two notable drawbacks: (a) it is likely to run into local minimum, and (b) convergence is slow. Thermal conductivity gas analyzer often works in adverse surroundings, which requires fast and accurate measurements. Therefore, a strong learning network is needed. This paper proposes a novel thermal gas analyzer using adaptive neuro-fuzzy inference system. The effectiveness and validity of the proposed method is verified by simulation studies using MATLAB. Fuzzy membership rules are created to allow regulation of learning parameters. Further, the fuzzy adaptive network model is constructed to train large data samples while the high precision compensation of sensor error is realized by the improved flow. Simulation results reveal that the convergence speed and output accuracy is improved and the learning parameters in thermal gas analyzer are automatically corrected by the proposed method in comparison with the back propagation algorithm of artificial neural network.

Due to the rapid growth of high performance electronics devices accompanied by overheating problem, heat dissipater nanocomposites material having ultra-high thermal conductivity and low coefficient of thermal expansion was proposed. In this work, a nanocomposite material made of copper (Cu) reinforced by multi-walled carbon nanotubes (CNTs) up to 10 vol. % was prepared and their thermal behaviour was measured experimentally and evaluated using numerical simulation. In order to numerically predict the thermal behaviour of Cu/CNTs composites, three different prediction methods were performed. The results showed that rules of mixture method records the highest thermal conductivity for all predicted composites. In contrast, the prediction model which takes into account the influence of the interface thermal resistance between CNTs and copper particles, has shown the lowest thermal conductivity which considered as the closest results to the experimental measurement. The experimentally measured thermal conductivities showed remarkable increase after adding 5 vol.% CNTs and higher than the thermal conductivities predicted via Nan models, indicating that the improved fabrication technique of powder injection molding that has been used to produced Cu/CNTs nanocomposites has overcome the challenges assumed in the mathematical models.

- by Faiz Ahmad and +3
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- Thermal Engineering, Powder Metallurgy, Composite Materials and Structures, Metallurgy

This study presents the experimental results of concrete bricks based macroencapsulated phase change material (PCM) in different capsule designs (circular, square and rectangular cross-sections). Eight concrete bricks (including a reference brick without PCM) are fabricated, and their thermal performance is tested under hot summer conditions of Al Amarah city, Iraq. The study considered several indicators such as the interior maximum temperature reduction (MTR), decrement factor (DF) and time lag (TL) to compared among tested bricks in addition to the thermal behaviour during melting and solidification of PCM. Results indicated that all PCM based bricks are performed better than the reference brick in which the maximum interior temperature is shaved and shifted. Moreover, the best thermal performance is reported for bricks of large PCM capsules number. Amongst others, the brick-based square cross-section PCM capsules showed the best thermal contribution where the average MTR of 1.88 • C, average DF of 0.901 and average TL of 42.5 min were obtained compared with the reference brick. The study concluded that PCM capsules' heat transfer area is the main parameter that controls PCM's thermal behaviour as long as all PCM capsules have the same PCM quantity and position. Therefore, excessive encapsulation area might influence the thermal performance of concrete brick and should be specified for the efficient use of PCM storage capacity.

- by Qudama Al-Yasiri and +1
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- Thermal Engineering, Sustainable Building Design, Sustainable Building Materials, Energy Efficiency in Buildings

In the past decade, rapid advancements of nanofluids science in many areas have been observed. In recent years, refrigerant-based nanofluids have been introduced as nanorefrigerants due to their better heat transfer performance. The objectives of this research include preparation, characterization and investigation of the thermophysical and migration properties of nanorefrigerants. Al2O3/R141b and TiO2/R141b
nanorefrigerants with various proportions of concentrations have been prepared to investigate their fundamental properties. Nanoparticles size, shape, and elemental
proportion have been characterized with Field Emission Scanning Electron Microscope (FESEM) and Transmission Electron Microscope (TEM). Moreover, this study investigated thermal conductivity, viscosity, and density of Al2O3/R141b
nanorefrigerants for different concentrations and temperatures. In addition, migration properties of Al2O3 and TiO2 nanoparticles with R141b refrigerant along with
lubricating oil have been investigated for different heat fluxes, initial liquid level heights, vessel sizes, insulation, nanoparticle sizes, and oil mixture. In this study, the thermal conductivity of Al2O3/R141b nanorefrigerant increased with the
augmentation of particle concentration and temperature. Besides, viscosity and density of the nanorefrigerant increased with the increase of volume fractions. However, these parameters decreased accordingly with the increment of temperature. Migration of nanoparticles during pool boiling increased with the increase of initial nanoparticle mass fraction, nanoparticle size, heat flux, and insulation. However,
migration of nanoparticles decreased with the increase of particle's self-density, boiling vessel size, and initial liquid level height. Therefore, nanoparticle has strong relationship with thermophysical and migration properties of refrigerants.

- by Dr. Mohammed Mahbubul Islam
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- Thermal Engineering, Renewable Energy

The aim of this study was to review the significant of waste heat recovery technologies as means of achieving sustainable energy development. Most developing nations of the World are faced with the enormous release of industrial waste heat of low temperature grade to the environment. Unlike material waste that is clearly visible, waste heat can be difficult to identify and evaluate both in terms of quantity and quality. Hence, understanding the availability of waste heat, and the ability to recover it, offer great opportunity to reduce energy costs and associated environmental impacts. Utilizing low-grade energy from waste heat sources is considered to offer a significant contribution to improving overall energy efficiency in the energy-intensive industrial sectors. The concept of industrial waste heat is explained, potential sources of waste heat from industries are identified, and the technologies available for waste heat recovery are presented in this study. From the review study, it is shown that about 72% of the global primary energy consumption is lost after conversion, while 63% of the considered waste heat streams arise at a temperature below 100 °C in which electricity generation has the largest share followed by transportation and manufacturing industry. The results of this study reveals that considerable amount of waste heat can be technically and economically recovered through sustainable technologies with prospective capacity for the much desired sustainable energy development. Specifically, in-depth utilization of waste heat resources can effectively moderate the rate of depletion of the fossil fuels and sufficiently reduce toxic emissions to within acceptable limits that are compatible to the projected time of full deployment of renewable energy (RE) source.

- by Tunde Fakeye
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- Thermal Engineering, Environmental Science

This paper introduces various electrical and thermal energy generation, consumption, and storage components in solar powered low-energy buildings. Dynamic management of such energy components is essential given the stochastic solar resources. Emphasis is put on power electronic HVAC (heating, ventilation, and airconditioning) drives, which can act as an effective electric swing bus to mitigate solar power variability. In doing so, grid power flows become substantially more constant, reducing the need for fast grid resources or dedicated energy storage such as batteries. The concept is equivalent to using building thermal energy as virtual dynamic storage in support of power grid operation. The paper defines a bandwidth over which such HVAC drives can operate. A practical band-pass filter is realized that provides 1) lower frequency bounds such that the building maintains consistent room temperature via the HVAC system as demonstrated by a thermal modeling study, and 2) upper frequency bounds that ensure commanded HVAC fan speeds do not update arbitrarily fast. The latter primarily avoids acoustic discomfort to users. The combination is illustrated by experimental results based on various update rates of a variable frequency fan drive over a sample of actual stochastic solar data. Building electrical and thermal energy systems modeling by MATLAB is addressed throughout the paper, including solar and HVAC systems as well as batteries and water tanks. Index Terms—Low-energy buildings, frequency domain analysis, grid-level energy storage, HVAC systems, solar energy, thermal storage, power electronic drives, complex system energy management

- by Yue Cao
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- Thermal Engineering, Photovoltaics, Complex Systems, Energy Efficiency Buildings

ABSTRACT Thermal effects are critical factors on the performance and life of a Polymer Electrolyte Membrane (PEM) fuel cell system. Heat generation in a fuel cell stack is largely influenced by the exothermic electrochemical reactions at the cathode. Due to non-uniformity of reactions over the MEA area, heat generation and temperature distribution over the stack is also theoretically non-uniform. This work attempts to profile the thermal performance of an industrial PEM fuel cell stack. The stack power generation and cooling rates at the heat exchanger were monitored under specific working conditions. The discussion focused on causes of the temperature gradient, heat generation, cooling effectiveness, and the quality of the heat exchanger. The analysis demonstrates a significant relationship between stack temperature and generated power to the heat exchanger performance and coolant conditions.

- by Wan Ahmad Najmi Wan Mohamed
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- Thermal Engineering, Thermodynamics, Renewable Energy, Heat Transfer
- by mohamed farag
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- Thermal Engineering, Industrial Engineering, Thermodynamic analysis

— In digital communication system, digital information can be sent on a carrier through changes in its fundamental characteristics such as phase, frequency and amplitude. The use of a filter plays an important part in a communication channel because it is effective at eliminating spectral leakage, reducing channel width, and eliminating interference from adjacent symbols (Inter Symbol Interference) ISI. It describe the developed and dynamic method of designing finite impulse response filter with automatic rapid and less error by an efficient genetic and neural approach. GA and Neural are powerful global optimization algorithm introduced in combinational optimization problems. Here, FIR filter is designed using Genetic, Neural approach by efficient coding schemes. We need to design these filters with some constraints imposed by requirements of the communication system in which we are going to use them. The use of optimization techniques have been proved to be quite useful towards the design of those digital filters with certain specifications. This paper reviews about the uses of optimization systems in digital filter design.

The influence of variables such as; refrigerant amount, chilling and cooling water temperature, throttle valve opening, cooling and chilling water flow rates, on the efficiency (coefficient of performance-COP) of a water to water carbon dioxide heat pump was investigated. Design of experiments was done using design-expert® 6 software for regression analysis. A response surface method known as central cubic design was used to provide optimum results with minimum experiments. Through multiple regression analysis, an empirical equation relating the COP to the variables was derived. Analysis of variance revealed that these regressions are statistically significant at 95% confidence level compounded with a very low standard deviation and a high adequate precision. The close relationship between the predicted COP values and the actual values further proves the worthiness of the empirical equation. It was observed that cooling water temperature had the highest influence followed by the chilling water temperature. Surprisingly, the amount of the refrigerant was third followed by the throttle valve opening. Understandably, chilling water flow rate had the least effect on the COP. Through response surface diagrams, the interactive influence of the variables were also observed. The COP values arrived at varied from 1.545 to 6.914 although if the variables were optimized fully within the scope of this study, a value of up to 11.8 could be achieved. Still, if the variables range is increased further, higher COP could be achieved. Finally, a discussion was done in a bid to explain these results.

- by Zhongjie Huan
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- Thermal Engineering

This paper analyzes the model of volume control of an innovative stratospheric airship concept designed to use hydrogen as a buoyant gas. This paper analyzes a mathematical model which allows modelling the airship volume changes with altitude. CFD evaluation at different altitudes has been performed. CIRA and Std. Atmosphere models have been compared.

- by antonio dumas and +1
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- Thermal Engineering, Controls, Airship structures, Airships

Having a small car running with low power can be achieved by reducing the aerodynamics drag, rolling resistance and mechanical frictions between the moving parts. The Shell Eco-Marathon competition held around the world with events in Europe, USA and Asia shows every year new techniques and ideas to reduce the power needed to drive the car. The record of over 3400 km on the equivalent of a single litre of fuel is an indication of how car can run efficiently. The problem with these low drag cars is the driver perception about the shape of the car. Although the tear drop shape is known as having the minimum drag, practically this shape cannot be used due to size and packaging limitations in addition to the safety issue. In this work, a low drag concept car is proposed using initial CAD design. The concept car is examined using a commercial CFD software by simulating the airflow around car. The spatial distribution of the pressure and velocity vectors are utilized to improve the car shape and to achieve a low drag force coefficient while keeping the down force at its minimum value. By changing the car front, underneath and rear shapes, it was possible to reduce the drag coefficient from 0.430 for the baseline to 0.127 for the final design, while meeting the competition regulations

- by Essam A
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- Thermal Engineering, Environmental Science
- by Ahmad Hadi
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- Thermal Engineering, Materials Science, Thermodynamics, Metallurgy

— Designing an efficient Distributed Database System (DDBS) is considered as one of the most challenging problems because of multiple interdependent factors which are affecting its performance. Allocation and fragmentation are two processes which their efficiency and correctness influence the performance of DDBS. Therefore, efficient data fragmentation and allocation of fragments across the network sites are considered as an important research area in distributed database design. In this paper presents an approach which simultaneously fragments data vertically and allocates the fragments to appropriate sites across the network. Bond Energy Algorithm (BEA) is applied with a better affinity measure that improves the generated clusters of attributes.

The paper presents results of an experimental investigation of convective drying of Idared apple in full recirculation laboratory scale dryer. The experiments were conducted with cube-shaped apple samples (side length 10 and 13 mm), without pre-treatment. The parameters of air stream over the tray with samples were fully controlled and adjusted in several sets of experiments, while always remaining in the following ranges: temperature 35–55 °C, relative humidity 10–30%, velocity 1–2 m/s. The drying kinetics of the apple samples was recorded, the results were analyzed and compared to the existing drying models. The analysis of the experimental results enabled derivation of correlations between drying parameters in a form k = f(T,RH), within Henderson & Pabis drying model MR = aexp(−kτ), as well as the calculation of effective moisture diffusivity during the process.► An experiment for low-temperature convective drying of apple cubes is conducted. ► A convective laboratory scale dryer with full air recirculation is built. ► The experiments are in ranges: 35–55 °C, 10–30% RH, 1–2 m/s, cube size 10 and 13 mm. ► The analysis of the results enabled derivation of drying parameters correlations. ► Different combinations of drying parameters can produce similar drying effects.

- by Ivan Zlatanović
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- Thermal Engineering, Thermodynamics, Renewable Energy, Drying Technology
- by CIC energiGUNE
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- Thermal Engineering, Nanofluids, Solar Power, Thermal Energy Storage

Pembahasan tentang Resume Mesin Diesel

- by Ghiffari Awliya Muhammad Ashfania
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- Thermal Engineering

In this work, the effect of infiltration method on the saturation rate of paraffin phase change material within graphite foams is experimentally investigated. Graphite foams infiltrated with paraffin have been found to be effective for solar energy storage, but it has been found that it is difficult to completely saturate the foam with paraffin. The effectiveness of the fill will have a significant effect on the performance of the system, but the data on fill ratio are difficult to separate from confounding effects such as type of graphite or phase change material (PCM) used. This will be the first detailed quantitative study that directly isolates the effect of infiltration method on fill ratio of PCM in graphite foams. In this work, the two most commonly reported methods of infiltration are studied under controlled conditions. In fact, the effect of the infiltration method on the paraffin saturation rate is found to be highly significant. It was found that the more commonly used simple submersion technique is ineffective at filling the voids within the graphite foam. Repeated tests showed that at least 25% of the reported open space within the foam was left unfilled. In contrast, it was found that the use of a vacuum oven lead to a complete fill of the foam. These high saturation rates were achieved with significantly shorter dwell times than in previously reported studies and can be of significant use to others working in this area.

- by Ron Warzoha
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- Thermal Engineering, Heat Transfer, Solar Energy, Graphite

The motivation of the research presented in this thesis was to investigate thermomechanical processes that appears during the convective drying of food materials in systems with air recirculation. The mathematical model was formed to describe the change of moisture ratio of the material during the time, by taking into account the influence of all relevant thermomechanical properties of drying air (temperature, relative humidity and velocity) on the drying process. Convective laboratory scale dryer with possibility of full drying air recirculation was designed and built in order to achieve and measure all relevant drying process parameters. Apples, potatoes and bananas were used in the experiments. The chosen materials were dried under the same drying conditions. Drying air temperature was in range 35-55 o C, relative humidity in range 10-30% and velocity in range 1-2 m/s. The apples were cut into cubes with 10 mm and 13 mm side dimension, potatoes were sliced into chips of 2 mm and 3 mm thickness and bananas were sliced into the cylinders with 6 mm and 7 mm thickness. Analysis of error appearance probability was performed. The effective moisture diffusivity was used to describe drying process efficiency. The experimental results confirmed that thermomechanical properties of drying air have significant influence on drying process. It was discovered that drying air, relative humidity could be ignored in some occasions. The performance of heat pump drying system was analyzed in order to discover system efficiency. The system energy and mass flows, air circulation behavior, drying air properties and system components behavior were monitored in order to calculate the main parameters of system performance. It was discovered that appropriate system performance optimization could increase system energy efficiency and reduce specific energy consumption. The results of mathematical model equation were compared with the experimental results and with the models and with the experimental results of the other authors, in order to be verified.

- by Ivan Zlatanovic
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- Thermal Engineering, Thermodynamics, Renewable Energy, Drying Technology

 Abstract— Distribution design involves making decisions on the fragmentation and allocation of data across the sites of a computer network. Multiple vertical splitting is the process of subdividing the attributes of a relation to generate fragments. In this paper, we propose an analysis for multiple vertical splitting algorithm using Slop Based Partitioning Algorithm (SBPA). This approach starts from the attribute affinity matrix and generates initial clusters based on the affinity values between attributes. Then, it uses the database according to optimal splitting solution to produce final groups that will represent the fragments. Then we analyzed these fragments according to their contribution level. The result is generated that shows how to find optimal solutions.

In recent year's commercialization of Renewable energy plays a vital role in extending the existence of fossil fuels. Solar energy is one of the easily available and most utilized energy sources all over the world. Solar energy is used in various forms like power generation, desalination, cooking, drying and water heating. This work concentrates on Domestic Solar Water Heater (SWH). Even though SWH is fitted in 75% of houses, inconvenience in SWH is unobtainable of hot water round the clock. Research for increasing the performance of SWH is by either modifying the design or using storage materials. In this work conventional sensible heat storage materials like pebbles, sand and inorganic salts used for latent heat storage materials like Sodium Chloride (NaCl), Potassium Chloride (Kcl), zinc Chloride (Zncl2), Carbamide and mixture of Zncl2, Kcl, Carbamide are employed. Inorganic salts and eutectic mixtures are used only as latent heat storage materials and not as sensible storage materials. In this work an attempt is made to study the performance of SWH using the latent heat storage materials as sensible heat storage.

- by vmln prasanna
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- Mechanical Engineering, Thermal Engineering, Solar Energy

In this study pongamia methyl ester was prepared by transesterification using potassium hydroxide (KOH) as catalyst and was used as fuel in a four stroke, water cooled, single cylinder, direct injection diesel engine. Pongamia methyl ester fuel blends (75% and 100%) were used for conducting the engine performance tests at varying loads (20%, 40%, 60%, 80%, and 100%). Tests were carried out over entire range of engine operation at varying conditions of load. The performance, combustion and emission characteristics were determined. Based on these, the parameters such as brake thermal efficiency, specific fuel consumption, exhaust gas temperature, emissions in exhaust such as CO, CO 2 , O 2 , HC and NOx were recorded. The results show that the blend of pongamia oil with diesel fuel can be used as an alternative fuel successfully in a diesel engine without any modification.

- by HAITER LENIN
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- Thermal Engineering, Composite Materials, Alternative Energy

Photo Gallery for A 90 MW Steam Power Plant - Introduction lecture

- by Mishaal A AbdulKareem
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- Thermal Engineering, Thermodynamics, Steam Turbines, Steam Boilers

Since decades, the only source of the material is reinforced alloys of such as iron, steel or aluminium are used in the automobile industry but due to high demand for performance. Researchers found introducing ceramic components can withstand elevated temperatures which are produced during working. Nowadays ceramics are used in Pistons, piston-skirts, cylinder heads, intake manifolds, etc. The work here is been carried out by scrutinizing different compositions of ceramics on a 3D model brake disc in replace of a traditional cast-iron disc. Apart from withstanding high temperature, foremost is heat dissipation to the airstream. Performing transient thermal analysis shows the characteristics of thermal stability, heat dissipation and other mechanical behaviour w.r.t various conditions. Giving the results of better thermo-mechanical stability over present materials such as thermal behaviour, strength to weight ratio, wear and tear resistance, withstanding chemical erosion subjected to acidic and caustic environments that occurs in other materials. I. INTRODUCTION Present day industries of aerospace and automobile are been upgrading to advance manufacturing techniques about brake discs using ceramic composites replacing present alloys to compete over different mechanical properties of elasticity, hardness, tensile strength at soaring temperatures keeping their wear and tear resistance to minimum using different materials to have the optimum strength to weight ratio. As ceramics deliver high performance in both dry and wet conditions of comfort, durability, resistance, corrosion and high-tech appeal. A ceramic is an inorganic non-metallic solid made up of either metal or non-metal compounds that have been shaped and then hardened by heating to high temperatures. In general, they are hard, corrosion-resistant and brittle. Traditional ceramics are clay-based, but high-performance or advanced ceramics are being developed from a far wider range of inorganic non-metal materials. Advanced ceramics have the properties of high strength, high hardness, high durability and high toughness. These advanced ceramics are generally oxides of elements or non-oxides (like borides, nitrides and silicide's) Production processes firstly involve thoroughly blending the very fine constituent material powders. After shaping them into a green body, this is high-temperature fired (1,600-1,800°c). This step is often carried out in an oxygen-free atmosphere. The high temperature allows the tiny grains of the individual ceramic components to fuse together, forming a hard, tough, durable and corrosion-resistant product. This process is called Sintering.

- by IJRASET Publication
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- Thermal Engineering, Discourse, Heat Transfer, Ceramics (Archaeology)
- by IJERT Journal
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- Engineering, Thermal Engineering

The narrow gauge steam locomotives of the Darjeeling Himalayan Railways are the existing examples of the external combustion engines, which played a key role for transportation in the region before the advent of the automobiles. However, their condition today is grim. In this paper we present the various technical shortcomings and suggestions for improvement of the Class B narrow gauge steam locomotives.

- by Samar Thapa
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- Thermal Engineering, Thermal Analysis, Steam Boilers

— Thermo-physical properties of butter, hydrogenated fat, palm oil, coconut oil, sunflower oil, and groundnut oil were examined. Experimental results revealed the highest slip melting point (38oC) and specific gravity for hydrogenated fat whereas the lowest slip melting point (-18oC) and hardness values for sunflower oil. However, sunflower oil showed the highest refractive index. The consistency of butter and hydrogenated fat was reported acceptable plastic and spreadable. Palm oil was found soft and spreadable. The melting curve of palm oil, butter, and hydrogenated fat showed two endothermic peaks. However, coconut oil, sunflower oil, and groundnut oil showed only one peak. The solid fat content (SFC) of butter, hydrogenated fat, palm oil, and coconut oil were found within the recommended range for baking performance. Melting enthalpy was strongly correlated to hardness (r = 0.8604, P < 0.001) of fat and oil samples. Correlation coefficient (r) of 0.8977 (P < 0.001) was found between SFC and hardness. The results strengthen the premise that hardness of the fat is not dependent solely on the SFC and as the results demonstrated that the melting enthalpy also plays a key role in influencing the hardness of fats and oils.

Many new technologies are emerging and developing in automobile sector and moreover it has
proven its importance in human life time to time. For the human comfort air conditioning is provided in vehicle.
In automobile air conditioning normally vapour compression refrigeration cycle is used. The cycle run on
engine power and consumes around 10% of the total power produced by the engine and thereby increases the
fuel consumption. To avoid this fuel consumption, the same air conditioning effect can be achieved by using
vapour adsorption system without using engine power. The work presented in this paper gives the overall idea
about design, development & implementation of water cooling system by using exhaust of the engine with same
condenser & evaporator unit. The exhaust is feed to adsorber bed which is filled with carbon activated charcoal
& R134a as a refrigerant. This refrigerant get evaporated and passed through the stainless steel coil which acts
as an evaporator. The normal temperature water is passed through this evaporator coil. For primary stage this
concept is implemented on two wheeler engine. This concept will be implement on four wheeler for air
conditioning purpose. The water cooling system is powered by exhaust heat using two control valve with same
condenser and evaporator unit. The cooling capacity for 2 liter water is estimated 0.28kW. A system has been
designed and developed. A cooling effect of 0.28kW can be obtained. The expected COP of the system is in the
range of 0.2 to 0.25. The dimensions of the system are compact. It can be easily accommodated on a domestic
two wheeler. The total weight of the system for a cooling capacity of 0.28 kW is 5kg. The heating time required
to achieve the cooling effect will be around 15 minutes. Total time to complete cycle will be around 45 minutes.
Keywords: Absorber bed, Ammonia, Evaporation, R134a, Refrigeration System.

- by yogesh khaladkar and +1
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- Thermal Engineering

Identify of potential risks is the first step in the management risk of software projects. It is a key step that other steps are based on it. In this paper a model is presented to improve the process of identifying potential risks. This model can vouch (assure) development of software projects. A matrix solution is given (is presented) to identify the levels of potential risks. Solutions and the causes of risks are classified based on the known and unknown, and also the levels were determind. The design of this model, in addition to strategy (admission, transfer) to avoid risks and probabilities are modified with new informations. A search algorithm (condition-action) is used to identify and prioritize potential risks based on sequence data structure. This algorithm has been implemented based on the C# codes and it also works on boolean variables. To implement the algorithm operating functions such as searching, planning, control, events, and management were used. To complete it these functions provided by the law-condition apply the potential risks are identified and then prioritized. Zero, and one decision variables to store intermediate results in their practice of inference, as intelligently manage event risks. The implementation of this model in various stages leading to optimized selection of the new solution, and output of model reduces the cost, schedule, and quality of software development. Also the risks and complexities and uncertainties are controlled. The validity of this method is assessed qualitatively using a practical example. This example relates to the users of ICT in training and education center in mazandaran were evaluated.

Future generation reusable re-entry vehicles must be capable of sustaining consistent repeated aero-thermal loads without damage or deterioration. This means that such structures should be able to withstand high temperatures engendered by aero-thermal re-entry fluxes due to the establishment of a hypersonic regime over the body. Thermal Protection Systems (TPS) are used to maintain a reusable launch vehicle structural temperature within acceptable limits during re-entry flights; that is internal temperature should not be higher than the limit required by the internal structure. TPS are usually composed of several layers of different materials. Heat transfer through a multilayer insulation during atmospheric re-entry involves combined modes of heat transfer: heat conduction and radiation through the solid, heat radiation to the outer space etc. In the framework of the TPS design activities, a procedure based on one-dimensional analytical solutions of transient non-linear analysis has been developed in order to estimate the temperature variation with time and space of a multi-layered body subjected to aerodynamic heating inside a radiating space. Furthermore a semi-analytical procedure, able to take also into account non-linear thermal properties, has been conceived. Since internal temperature values of TPS of re-entry vehicles cannot exceed certain values, these procedures allow to quickly evaluate these temperature values and the preliminary size layer thicknesses without resorting to numerical solutions.

- by Oronzio Manca and +1
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- Thermal Engineering, Heat Conduction, Thermal Shield

This was a white paper submitted at my Ex-organisation on the noise control of vacuum cleaners

Desalination plays critical role in filling the gap between fresh water demand and availability in water scarce Sultanate of Oman since 1976. Installed desalination capacity in the country has almost increased by 60 times that in 1976 with increasing fresh water demand. Even though desalination share in meeting the fresh water demand is increasing, 80-85% of fresh water demand today is still satisfied with ground water. This is leading to increased soil salinity in recent years affecting the crop production. All the planned and installed desalination plants in the country use conventional fuels for their operation. None of the plant is based on any form of renewable energy source. Consumption of fossil fuels for the operation of plants is increasing at an average rate of 3-5% affecting the net export for the country. Sultanate of Oman is considered to be one of the most suitable destinations for solar energy applications and can play a vital and sustainable role in meeting the gap b...

— Preliminary investigation on laterite soil sample collected from old Julius Berger borrow pit in Ejio area of Arigbajo in Ifo Local Government Area, Ogun State (6.849˚N, 3.211˚E), classified the soil as A-2-7(4) [AASHTO classification]. The soil was mixed with Banana Leaf Ash (BLA) in varying percentages of 0%, 2%, 4%, 6%, 8%, 10%, and 12% and the effect of BLA on the soil sample was determined for Liquid Limit, Plastic Limit, Compaction (MDD % OMC), CBR and Unconfined Compression Test. These tests were repeated for the soil sample + BLA + cement. The results of the treated soil showed increase in the plastic limit, liquid limit, plasticity index and optimum moisture content (OMC) as the BLA content increased. The values of maximum dry density (MDD), California Bearing Ratio (CBR) and Unconfined Compressive Strength (UCS) increased up to 2% BLA before starting to decrease steadily. This implies that the Banana Leaf Ash (BLA) is a weak pozzolan. Index Terms— Laterite; Banana Leaf Ash (BLA); Stabilization; California Bearing Ratio (CBR); Unconfined Compressive Strength (UCS)

Heat Exchanger's function in the Refrigerator is to increase the amount of liquid at the entrance of the evaporator to increase the refrigeration capacity (due to the decrease of enthalpy on the exit of the capillary). At the same time, increase the temperature of the refrigerant at the compressor inlet to avoid that liquid arriving at the compressor damaging it. It also avoids external condensation on the suction tube caused by the cooler refrigerant. Suction line and capillary tube are placed in contact to improve the C.O.P. of the refrigeration system. In Capillary tube-Suction line heat exchanger, the flows should be in the opposite direction (capillary and suction tube) to have better heat exchange effectiveness. The present research work aims at investigatingthe change in the material of Heat exchanger from copper to aluminum and analyses the change in performance of the VCRS system. Thus, the analytical and simulation study with the three types of heat exchanger i.e. Total copper heat exchanger, Partial aluminum heat exchanger, and Total aluminum heat exchanger is done to identify the impact on COP and RE with the change of material.

- by Nikhil Aniruddha Bhave and +1
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- Thermal Engineering

Phase change materials (PCMs) are known to be excellent candidates for thermal energy storage in transient applications. However, enhancement of the thermal conductivity of a paraffin-based PCM is required for effective performance, particularly during solidification where diffusion is the dominant heat transfer mode. This study experimentally examines the effect that graphite nanofibers (GNFs), aspect ratio and power density have on both thermal storage and solidification time of a PCM which is embedded between two sets of aluminum fins. Additionally, a figure of merit is introduced in order to quantify the effectiveness of each of these three parameters with respect to solidification time. GNF enhancement was shown to reduce the maximum temperature in the thermal containment unit (TCU) by 48%. It was also found that for aspect ratios of 1, the GNF enhancement shortens solidification time by as much as 61% over the paraffin samples. This research indicates that GNF impregnation into phase change materials is an effective method for the enhancement of the thermal energy storage and the solidification of paraffin-based phase change materials.

- by Ron Warzoha
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- Thermal Engineering, Nanofibers, Heat Transfer, Nanocomposites

High temperature in common fire causes changes in physical characteristics and mechanical strength of the materials used in the structures. In both steel and concrete, such characteristics deteriorate during the exposure to fire, and the structure load capacity and stiffness are reduced significantly with the increasing temperature. This work is on advanced analysis context of structures under fire, and it aims to develop a computational system for analysis of steel, concrete and composite structures in fire situation, based on the finite element method. The use of advanced analysis as a methodology of analysis/design of structures has various advantages. Among these advantages, there is the capture of strength limit and stability of a structural system and its members directly, without the need for separate verification of each member capacity. This provides a more realistic analysis and determine adequately the performance of a structure in a real fire. To achieve the objective, the CS-ASA (Computational System for Advanced Structural Analysis) is used and expanded to advanced analysis of structures in fire situation, taking advantage of existing features and adding new ones. Two new modules were created: CS-ASA/FA (Fire Analysis) and CS-ASA/FSA (Fire Structural Analysis). The first aims to determine the temperature field in the cross section of the structural elements by FE thermal analysis in permanent and transient regimes. The second was created to perform the inelastic second-order analysis of structures under fire considering the refined plastic hinge method coupled to strain compatibility method. The adopted numerical methodology is described and, for a more comprehensive validation of the implemented modules, various structural systems under fire are analyzed.

- by Ricardo A M Silveira and +1
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- Thermal Engineering, Structures and Fire Engineering
- by gugi prastantyo
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- Thermal Engineering

This article focuses on the usage of geothermic energy in greenhouses, its energy-, economic efficiency-, and sustainability-related questions. The most notable cost greenhouses produce during operation is the usage of heat energy, which is why when planning a system for this purpose, the energetic analysis of the solution to be used is one of the most important factors. The presented analyses suggest that of the energy resources currently available and usable, geothermic energy has the lowest unit cost. In the case of greenhouse heating, this method turned out to be the most cost-effective among all solutions using any of the energy resources. Regarding the environmental aspect, the CO 2 emission rates of the various heating methods have been examined as well. Using the thermal water of the greenhouses before reinjection is an efficient way of energy utilization. Even though the firewood and pellet boilers look the most efficient forms for the first time, past experiences proved them to be the most expensive ones as well. Therefore, it can be stated that the utilization of geothermal energy is the best solution for greenhouse heating, from the perspectives of economic and environmental aspects as well. Based on the previous observations in terms of environmental and economic efficiency this paper aims to discover the opportunities for high-scale thermal utilization in Hungary in order to meet its future renewable targets.

- by Bálint Horváth and +1
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- Thermal Engineering, Environmental Sustainability, GHG Emissions, Greenhouse Technology

— Stealth refers to the act of trying to hide or evade detection. Stealth technology is ever increasingly becoming a paramount tool in battle especially " high technology wars " if one may occur in the future where invincibility means invincibility. Able to strike with impunity, stealth aircraft, missiles and warships are virtually invisible to most types of military sensors. The experience gained at the warfront emphasizes the need to incorporate stealth features at the design stage itself. The other purpose is to share the recent achievements related to the advanced composite materials used on various aero structures across the globe. Also discussed are the possibilities of achieving stealth capability on our existing fleet of fighter and bomber aircrafts of our Indian Armed forces using composite and smart materials. Stealth technology also known as LOT (Low Observability Technology) is a technology which covers a range of techniques used with aircraft, ships and missiles, in order to make them less visible (ideally invisible) to radar, infrared and other detection methods. Stealth Technology essentially deals with designs and materials engineered for the military purpose of avoiding detection by radar or any other electronic system. Stealth aircraft are aircraft that use stealth technology to make it harder to be detected by radar and other means than conventional aircraft by employing a combination of features to reduce visibility in the visual, audio, infrared and radio frequency (RF) spectrum. Well known examples include the United States' F-117 Nighthawk (1980s-2008), the B-2 Spirit "Stealth Bomber," and the F-22 Raptor.

This study examines the selection of the best air gap to a model solar passive solar system chosen for heating in a cold climate based on instantaneous efficiency. The experiments have been performed on a passive solar system, which has been constructed from insulation sandwich panels in all sides except the south façade, which has been built from insulation sandwich panels on all sides except the south façade, where Trombe wall has been built in it, which is constructed from reinforced concrete and their exterior surface has been painted with dark black color, and covered with a single transparent glass layer. Five sets of experiments have been performed on the test system by changing the width of the air gap from 30 to 10 cm under the weather conditions in January 2017 in the city of Kirkuk (Iraq). The experimental results have showed that the 33 to 36% of the absorbs energy by Trombe wall has been converted to instantaneous energy provided to the heating space during the day. In addition, the results of the energy analysis of experimental equations have been produced to assess the efficiency of the system; they show that the 15 cm air gap has a better case when applying the same parameters, this result is consistent with an experimental study conducted by R. L. Casperson and C. J. Hocever, 1979. Nomenclature Trombe wall area [m 2 ] Vent area [m 2 ] A W Window area [m 2 ] B Width of the air gap [m] Specific heat of air [J/kg °C] Gravitational acceleration [9.81 m/s 2 ] Solar intensity incident on the absorbent surface [W/m 2 ] ℎ Average heat transfer coefficient on the glass side [W/m 2 °C] ℎ Average heat transfer coefficient [W/m °C] h o Surrounding heat transfer coefficient [W/m 2 °C] ℎ Radiant heat transfer coefficient within the air gap [W/m 2 °C] ℎ Average heat transfer coefficient on the absorbent side [W/m 2 °C] Distance between vents [m] Thermal conductivity of the air [W/m °C] k g Thermal conductivity of glass [W/m °C] ̇ Air mass flow rate [kg/s] Convection heat transfer [W] q L Heat loss to the surrounding [W] Useful energy [W] Ventilation energy [W] T a Ambient temperature [°C] T ab Absorbent temperature [°C] Inside surface of glass temperature [°C] Trombe wall temperature from the inside test system [°C] Mean air gap temperature [°C] Inside test system temperature [°C] Outlet temperature from the air gap [°C] u Wind speed [m/s] U L Overall heat transfer coefficient [W/m 2 °C] ̅ Average air velocity within the air gap [m/s] Glass thickness [m] The volume coefficient of expansion [K-1 ] Absorbent surface emissivity Glass emissivity Solar system efficiency Kinematic viscosity [m 2 /s] Air density [kg/m 3 ] Stefan-Boltzmann constant [5.669×10-8 W/m 2 K 4 ] Gr Grashof number Nu Average Nusselt number Pr Prandtl number Ra Rayleigh number

Low cyclic fatigue analysis at room temperature and crack growth rate under isothermal fatigue at 300-600 °C temperature ranges produced in AISI 420 martensitic stainless steel, using un-cracked solid cylinder specimen. The crack growth monitoring is obtained by using the DCPD machine. The research observes that the fatigue life reduces with increasing the surface roughness condition, while the behaviour of the material at room and high temperature to produce an initial hardening, followed by slow extension until fully plastic saturation then followed by crack initiation and growth eventually reaching the failure, and the effects of increasing temperature decrease the crack initiation period and also the crack length. The fatigue crack growth rate increase with stress intensity factor, and the crack growth rate at 600 °C test temperature less than 500 °C, due to the creep-fatigue taking place.

- by Mohammed Ali Nasser Ali
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- Thermal Engineering, Thermodynamics, Fatigue crack growth