Computational Fluid Dynamics (CFD) Research Papers (original) (raw)

Using CATIA V5 design software a model was designed on the platform of Unmanned Combat Aerial Vehicle (UCAV).Computational Fluid Dynamics (CFD) Analysis was performed on the ANSYS Workbench 14.0(Fluent) of the UCAV. The Design was particularly done for low speed and high Angle of Attack (AOA) criteria. Important results were interpreted such as lift, drag and lift to drag ratio for various AOA which eventually leads to determining stall angle of the UCAV. Primitively stall angle of the UCAV is found to be 30 degrees and the lift to drag ratio as 7.63, thus making UCAV to have high stall angle at lower speeds. 100-120m/s are taken for lower speed phenomena, density of air being constant at 1.22 kg/m 3 .

The use of turbochargers has increased in response to strengthened automotive exhaust emission and fuel consumption regulations for global environmental protection. Most centrifugal compressors are required to operate over a broad range of flow rates and to provide a high pressure ratio with high efficiency. The internal flow of a centrifugal compressor is very problematic with 3-dimensional and unsteady flow phenomena, and the analysis of flow phenomena and expansion of the operational range are difficult problems. Review is done for gathering the efficient method for designing and analyzing the centrifugal compressor. In order to meet these demands the application of variable geometry techniques is often considered and applied.

In this paper, CFD investigation has been considered to break down the stream examples of united Divergent nozzle of three distinct shapes utilizing three dimensional model, which unravel the administering condition by a control volume technique. The target of this paper is to concentrates at the variety of parameters like speed, static pressure, turbulence intensity, and all out temperature in the three nozzles being utilized. The demonstrating for cone shape, bell & Triangular molded nozzle is done and for triangular nozzle is planned in ANSYS Workbench and discretization process and the investigation are done in FLUENT.

This review paper contains the basic concept of intake manifold. Intake manifold is the breathing system of the car engine which supplies air to the engine cylinders where the combustion of the fuel occurs. The review paper contain SAE is the society of automotive engineers which is working for the automotive industry, educators and students. SAE India organizes formula student car racing championship name SUPRA every year. In this event a team of students has to follow all rules and regulations provided in rulebook which is designed by SAE committee. This paper contains basic methodology and technology adopted for designing intake manifold for 600 cc SUZUKI GSXR bike engine.

Most of the fossil fuel & Cement Plant waste heat based thermal power plants are facing the problem of Boiler Super Heater tube leakage due to high flue gas Temperature. This will affect the working of power plant and income in general. The research is to study boiler super heater tube leakage problem and find the causes of tube leakages with the help of Computational Fluid Dynamics simulation. An Auto CADD 2-D modeling of super heater is performed and Import to Computational Fluid Analysis software where the temperature of flue gases over the Super Heater Tubes using the actual boundary conditions has been studied. The Computational Fluid Dynamics results will be useful for to avoid the same in future projects and can be avoid the leakage in already running the Thermal Power plants with providing the Shield arrangement over the critical zone of super heater tubes to reduce the erosion and restricting Super Heater Tubes

Heat transfer is the key to several processes in industrial application. In a present days maximum efficient heat transfer equipment are in demand due to increasing energy cost. For achieving maximum heat transfer, the engineers are continuously upgrading their knowledge and skills by their past experience. Present work is a skip in the direction of demonstrating the use of the computational technique as a tool to substitute experimental techniques. For this purpose an experimental set up has been designed and developed. Analysis of heat transfer in spiral plate heat exchanger is performed and same Analysis of heat transfer in spiral plate heat exchanger can be done by commercially procurable computational fluid dynamic (CFD) using ANSYS CFX and validated based on this forecasting. Analysis has been carried out in parallel and counter flow with inward and outward direction for achieving maximum possible heat transfer. In this problem of heat transfer involved the condition where Reynolds number again and again varies as the fluid traverses inside the section of flow from inlet to exit, mass flow rate of working fluid is been modified with time. By more and more analysis and experimentation and systematic data degradation leads to the conclusion that the maximum heat transfer rates is obtained in case of the inward parallel flow configuration compared to all other counterparts, which observed to vary with small difference in each section. Furthermore, for the increase heat transfer rate in spiral plate heat exchanger is obtain by cascading system.

In the present study, laminar flow and heat transfer of nanofluid water/single-wall carbon nanotubes have been investigated in a novel design of double layered microchannel heat sink (MCHS). Present investigation has studied the dimensionless values of truncated lengths (k) of 0, 0.4, 0.8 and 1. Studied Reynolds numbers were 500, 1000 and 2000. The effect of volume fraction of nanoparticles in the Newtonian suspension of water based nanofluid was studied for values of 0, 0.04 and 0.08. The results showed that the thermal resistance and ratio of maximum and minimum temperature difference for bottom wall of microchannel as well as the ratio of thermal resistance decrease by increasing the nanopar-ticles volume fraction and decrement of k. The Performance evaluation criteria (PEC) factor on the bottom of channel increases in all ratios of k by augmenting volume fraction of nanoparticles.

The cooling principle of open-top greenhouse is taking advantage of vertical convection of air caused by thermal buoyancy to expel the hot air from the greenhouse. For cooling in the greenhouse in summer, many studies have demonstrated a significant effect. But the problem of the accumulated heat in the greenhouse is greatly affected by the meteorological environment of the geographical location. Even in the same area, environmental conditions inside the greenhouse vary due to different conditions, such as seasons, temperature difference between day and night, building type, surrounding environment and so on. Therefore, it's difficult to make an overall assessment of the effect provided by the open-top greenhouse in a traditional way. Using CFD (Computational Fluid Dynamics) technology to make the analysis of cooling effect in open-top greenhouse does not require a lot of resources to build physical facilities, but is able to achieve a certain effect. Therefore, the study is conducted to do simulation for the existing open-top greenhouse at the Taiwan Agricultural Research Institute (TARI), Council of Agriculture, Executive Yuan. Meanwhile inside and outside the greenhouse, temperature and humidity sensors of WSN (Wireless sensor network, WSN) transmission interface and a simple meteorological station are set up to record and verify the observations with the simulation results. It is expected to build the techniques of assessing cooling effect by estimating the temperature distribution within the greenhouse according to meteorological data of outdoor environment. Based on the results obtained from this study, it showed that the top temperature in the greenhouse can be dropped by about 3.7 ℃ at noon for the open-top greenhouse without any cooling equipment. The simulation results also showed a consistent trend with those observations. From this study, when the settings of the CFD simulation conditions are properly provided, the simulation of cooling in the greenhouse with CFD has a very high credibility. Hence, it is feasible to analyze in this way. It is suggested that assessment by using CFD technology be conducted first before building a physical greenhouse facility to improve project quality and reduce design errors.

Phase change materials (PCM) present great potential for energy efficiency gains in thermal systems by storing solar energy or waste heat in industrial processes. This is due to the great amount of energy stored per mass unit within a small temperature range. In this paper we focus, by means of the numerical investigation, on the solidification process of the PCM erythritol in spheres, having 10, 20, 30 and 40 mm diameter, under wall temperatures of 10, 15, 20, 25, 30 and 40 K below the phase change temperature of the material. The problem is considered two-dimensional in geometry and transient in time. The numerical model here adopted consists of mass, momentum, energy and volume fraction equations. The results have been initially validated by comparison with data found in literature. Afterwards, analysis of the convective streams on the liquid PCM, liquid fraction, heat flux in the sphere wall and total solidification times have been widely illustrated. The liquid fraction suffers a sharp reduction at the beginning of the solidification process due to the high heat flux at the initial times. As the solid layer adjacent to the shell increases, it causes an augmentation of thermal resistance, significantly reducing the heat flux. The shape of the curve representing the solid fraction shows similarity with the S-curve pattern of solidification. The total solidification time proved to be dependent on both the diameter length and the temperature difference ΔT (between phase change material and wall temperature), being its influence reduced for lower temperature values. Finally, the liquid fraction results, as a function of Fourier and Stefan numbers, have been employed to amend a dimensionless correlation found in literature.

FEM (finite element method) is an essential and powerful numerical method that can explicitly optimize the design process of electrical devices. In this paper, the employment of FEM tools such as SolidWorks, COMSOL and ANSYS is proposed in order to aid electrical apparatuses engineering and modeling-those are arc chambers of modular circuit breakers. Procured models of arc chambers have been undergoing simulations concerning heating, electric potential distribution, electric charge velocity and traverse paths. The data acquired has been juxta-positioned against experimental data procured in the Short-Circuit Laboratory, Warsaw University of Technology. The reflection of the theoretical approach was clearly noted in the experimental results. Mutual areas of the modeled element expressed the same physical properties and robustness errors when tested under specific conditions-faithfully reflecting those which were experimented with. Moreover, the physical phenomena essential for electrical engineering could be determined already at the model stage. This procedure proved highly valuable during designing/engineering work in terms of material economy.

- by Michał Szulborski and +1
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- Finite Element Method (FEM), Computational Fluid Dynamics (CFD), Thermal Analysis, Miniature Circuit Breaker (MCB)

Theoretical analysis of turbines for predicting of operating characteristics is a complex and poor way which gives only values and details of flow field behavior and causes for loss of efficiency cannot be investigated. Computational Fluid Dynamics (CFD) analysis is a robust technique for prediction of performance characteristics of hydraulic machineries and the actual fluid flow behavior can be observed. In this study the CFD analysis of a Francis hydraulic turbine is carried out which was selected for operation at a hydropower station on Kunar River in Afghanistan during some theoretical designs and calculations. Francis turbine is simulated based on designed data and operating behavior of turbine is predicted and fluid flow in turbine domain is observed.

This paper presents the effect of blade thickness on the hydraulic performance of a mixed-flow pump impeller. For the numerical analysis, three-dimensional steady-state Reynolds-averaged Navier-Stokes (RANS) equations are discretized using the finite volume method with the shear stress transport (SST) turbulence model. The equations were solved using hexahedral grids to analyze the internal flow in the mixed-flow pump impeller. The blockage concept is employed to express the quantitative amount by the variation in the blade thickness. The effects of hydraulic performance on the blockage amount are systematically analyzed with the variation in the best efficiency point (BEP) in the performance curve. The detailed flow characteristics with the blockage effect are analyzed and discussed.

- by Yong-In Kim
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- Numerical Simulations, Computational Fluid Dynamics, Numerical Analysis, Pumps

Hydraulic flocculation becomes a promising approach that commonly used for water and wastewater treatment works because of less energy and maintenance costs are needed when compared with mechanical flocculation. Swirl flow hydraulic clari-flocculators can be described as reactor clarifiers without mechanical mixing. The main objective of the present study is the determination of the optimal configuration of swirl flow hydraulic clari-flocculators in terms of tapering of velocity gradient, head loss in the flocculation zone, and sediments collection in the sludge hopper. For this, the best sizing of sludge hopper and the optimum diameter aspect ratio were then determined by computational fluid dynamics method (CFD). The obtained results reveal that the optimum diameter aspect ratio ranges between 0.2-0.4 for optimal configuration of swirl flow hydraulic clari-flocculators in terms of tapering of velocity gradient, head loss in the flocculation zone, and sediments collection in the sludge hopper.

Numerical analysis was carried out to investigate the influence of the setting angle and chord length on the pressure distribution especially for the shroud span of an axial fan. The setting angle was referred to as AOA (angle of attack). The aerodynamic performance of an axial fan with the change of setting angle and chord length was presented, and the unstable pressure distribution was discussed in detail. The airfoil of an axial fan was based on the NACA 3512. The influence of the setting angle was observed with the designed sets which were rotated based on the center of gravity for the blade. The chord length was adjusted while maintaining the setting angle. For each design parameter, 5 sets were designed to conduct the single-factor analysis, respectively. The setting angle had a sensitive effect on the aerodynamic performance of an axial fan. The pressure distribution became unstable related to the setting angle of the shroud span. On the other hand, the chord length was only proportional to the pressure rise and had a little effect on efficiency.

Hydraulic flocculation becomes a promising approach that commonly used for water and wastewater treatment works because of less energy and maintenance costs are needed when compared with mechanical flocculation. Swirl flow hydraulic clari-flocculators can be described as reactor clarifiers without mechanical mixing. The best sizing of sludge hopper and investigation of the optimum diameter aspect ratio by computational fluid dynamics are the main objectives of the present study for optimal configuration of swirl flow hydraulic clari-flocculators. The obtained results reveal that the optimum diameter aspect ratio ranges between 0.2-0.4 for optimal configuration of swirl flow hydraulic clari-flocculators in terms of tapering of velocity gradient, head loss in the flocculation zone, and sediments collection in the sludge hopper.

The development of chemical reactor network (CRN) models to predict the NOx emissions is very important for the modern combustion system design. In this study, the new chemical reactor network models are constructed based on the computational fluid dynamics (CFD) to simulate the burning process of the industrial combustor. The boundary and the operating conditions used for these CRN models reflect the typical operating conditions of the industrial combustor. The global mechanism has been developed by GRI 3.0 in the UW chemical reactor code. For the reliability of the predictive models, the models were analyzed and compared to the experimental industrial combustor research.The results of the CRN application to predict the NOx emissions show very goodagreement with the experimental data from Korea Electric Power Research Institute. Finally, the CRN models have shown to be efficient estimating accurately NOx emissions with a very short response time.

Planning, construction and rehabilitation of hydropower stations have important role in sustainable economic growth of countries. Hydraulic turbine is the most precious element of hydropower station and its design and optimization requires wide range of investigation. Transient flow in hydraulic turbines is an interesting phenomenon and unsteady investigation of hydraulic turbine is an important issue for all investigators which also carried out in this study. Transient analysis of hydraulic Francis turbine is done here using CFD method the pressure fields and velocity fields are determined. Different discharges and guide vane angles are analyzed and performance characteristics of the hydraulic Francis turbine are obtained with its efficiency perspective.

This study presents the use of a new chemical reactor network (CRN) model and non-uniform injectorsto predict CO emission pollutant in gas turbine combustor. The CRN uses information from Computational Fluid Dynamics (CFD) combustion analysis with two injectors of CH4-air mixture. Theinjectors of CH4-air mixture have difference lean equivalence ratio, and they control fuel flow to stabilize combustion and adjust combustor’s equivalence ratio. Non-uniform injectoris applied to improve the burning process of the turbine combustor. The results of the new CRN for CO prediction in the gas turbine combustor show very goodagreement with the experimental data from Korea Electric Power Research Institute.

Chemical pre-precipitation becomes one of the best options of chemical treatment of sewage. In the present study, chemical pre-precipitation was processed via swirl flow hydraulic clari-flocculators, which were investigated using the steady state analysis versus the simulation using of computational fluid dynamics (CFD) software for the optimal model configuration, as well as the design equations of swirl flow hydraulic clari-flocculators were derived in the present study. From the obtained results, it can be demonstrated that up flow flocculation relatively improves regularity of tapering of velocity gradient rather than down flow flocculation. Furthermore, gravitational acceleration helps to form supplementary tapering in values of velocity gradients for up flow flocculation in contrast to down flow flocculation where gravitational acceleration negatively affects on tapering of velocity gradient.

This study is concerned with reviewing and analyzing methods used in early design stages to mitigate wind effects on high-rise buildings. In order to mitigate wind effects on structures and specifically high-rise buildings, early stage aerodynamic design decisions are made. Architects try to mitigate the wind effects on buildings by choosing the right form configuration like tapering or setbacks, etc., or by making vital decisions in the early design stage. However, structural engineers utilize the structural system that can best counter-act forces acting on the stability of the building. For both architects and engineers there are many tools which can be used in early design including advanced analysis methods, wind tunnel testing and wind studies combined with Computational Fluid Dynamics (CFD) simulations. This study reviews general architectural and structural design configurations performed in the early phases of the design process, for achieving structural stability, comfort and cost control. The research methodology depends on the study and analysis of different international building examples, and also by reviewing two local high-rise building cases in Amman, Jordan. The study concludes that there are many architectural aerodynamic configurations for the purpose of mitigating wind loads, which can be used as guidelines in the early design phases.

Nuclear engineering requires computationally efficient methods to simulate different components and systems of plants. The Lattice Boltzmann Method (LBM), a numerical method with a mesoscopic approach to Computational Fluid Dynamic (CFD) derived from the Boltzmann equation and the Maxwell-Boltzmann distribution, can be an adequate option. The purpose of this paper is to present a review of the recent applications of the Lattice Boltzmann Method in nuclear engineering research. A systematic literature review using three databases (Web of Science, Scopus, and ScienceDirect) was done, and the items found were categorized by the main research topics into computational fluid dynamics and neutronic applications. The features of the problem addressed, the characteristics of the numerical method, and some relevant conclusions of each study are resumed and presented. A total of 45 items (25 for computational fluid dynamics applications and 20 for neutronics) was found on a wide range of nuclear engineering problems, including thermal flow, turbulence mixing of coolant, sedimentation of impurities, neutron transport, criticality problem, and other relevant issues. The LBM results in being a flexible numerical method capable of integrating multiphysics and hybrid schemes, and is efficient for the inner parallelization of the algorithm that brings a widely applicable tool in nuclear engineering problems. Interest in the LBM applications in this field has been increasing and evolving from early stages to a mature form, as this review shows.

The paper presents response of tall buildings using Computational Fluid Dynamics (CFD) software subjected to constant and varying wind velocity. The response of the buildings when subjected to wind load is studied by creating the models in ANSYS. Twelve models were chosen from previous wind tunnel studies and were subjected to constant and varying wind velocity in FLUENT. Through a comprehensive investigation on the buildings of different aspect ratio, wind-induced response of the structure is predicted. A Comparison of the CFD analysis with the previous studies are made. It is observed that the aerodynamic performance is different for solid-air interaction, when the velocity is varying along the height.

- by IAEME Publication
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- Aerodynamics, Tall Buildings, ANSYS FLUENT, Computational Fluid Dynamics (CFD)

The combination of machine learning and numerical methods has recently become popular in the prediction of macroscopic and microscopic hydrodynamics parameters of bubble column reactors. Such numerical combination can develop a smart multiphase bubble column reactor with the ability of low-cost computational time when considering the big data. However, the accuracy of such models should be improved by optimizing the data parameters. This paper uses an adaptive-network-based fuzzy inference system (ANFIS) to train four big data inputs with a novel integration of computational fluid dynamics (CFD) model of gas. The results show that the increasing number of input variables improves the intelligence of the ANFIS method up to R = 0.99, and the number of rules during the learning process has a significant effect on the accuracy of this type of modeling. Furthermore, the proper selection of model's parameters results in higher accuracy in the prediction of the flow characteristics in the column structure. ARTICLE HISTORY Abbreviation g Gravitational force (m s −2) k Turbulent kinetic energy for modeling of dispersed phase (m 2 s −2) M I Interfacial force (N m −3) M D Drag force for modeling of dispersed phase (N m −3) P The pressure in the reactor (N m −2) MFs Membership functions for ANFIS Greek Symbols ε Turbulent energy dissipation rate per unit mass (m 2 s −3) ∈ phase holdup (-) ¯ ∈ Average phase holdup (-) ρ Density of phases (kg m −3) μ T Turbulent viscosity (Pa s −1)

The present paper work is directed to a device located at the intake port at the junction of the intake manifold and the engine head. This location allows the device to be used with any type of carburetor or fuel injection system. It is the object of the present device to utilize at least three fixed, helically twisted blades to impart additional swirl mixing of the fuel/air mixture. This fuel/air mixture has already been pre-heated by its travel through the intake manifold. The "violent swirl" created by the device provides a more uniform fuel/air mixture, thereby causing a more complete and efficient combustion. The overall result of using the device is better gas mileage, increased performance, easier starting, and less pollution. The object of the project work to improve the fuel/air mixture of the fuel injected engines, preventing valves from being burned or eroded by clogged injectors. As a result of forcing the air to enter the intake port in a high velocity swirl, there is disruption of any direct fuel streams upon the head of the cylinder intake valve which occur as a result of clogged injectors. Another object of the project work is to provide a device that improves the homogeneity of the fuel/air mixture delivered by the carburetor to the cylinders of an internal combustion engine with little or no obstruction in the mixture flow resulting in no starving of the engine. Another object to deliver the fuel/air mixture to the center of the cylinder for a uniform flame front. The swirling mixture delivered by the present invention results in cleaner, more-efficient combustion.

- by IJSRD Journal
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- Internal Combustion Engine, Computational Fluid Dynamics (CFD), Catia V5, Swirl