Cfd

Blood flow simulations in computational fluid dynamics (CFD) are seen as a very attractive solution for diagnosing diseases. The main objective of this work is to simulate blood flow in healthy arteries. The governing equations for the Sisko model are presented in cylindrical coordinates. The finite volume method is used for the velocity and wall shear stress at healthy arteries. It is observed that the velocity profile increases due to an increase in Sisko fluid parameters and the radius of healthy arteries. With regard to the fact that blood flow in healthy arteries is non-Newtonian, the fluid obeys the Sisko fluid model. We contemplate that due to an increase in Sisko fluid parameters and the radius of healthy arteries, the wall shear stress profile increases and decreases, respectively.

Heat transfer simulation within heating furnaces is of great significance for prediction and control of the performance of furnaces. In this paper, a set of models is proposed to solve heat transfer problems in a loaded furnace. Furthermore, a 2-dimensional algorithm based on a finite difference method is presented. The heat transfer models are integrated with a furnace model to simulate the heating process of workpieces. Temperature variation of the workpiece with time is predicted by the system. An experiment is carried out for validation of the system. Themain objective of this work is to evaluate the behavior of a heated enclosure, when variable radiant panels are introduced. Experimental investigation shows that their efficiency depends on their position.

A ‘Hybrid electric vehicle' is a vehicle which relies not only on batteries but also on an internal combustion engine which drives a generator to provide the electricity and may also drive a wheel. It has great advantages over the previously used gasoline engine that drives the power from gasoline only. It is a major source of air pollution. The objective is to design and fabricate a two wheeler hybrid electric vehicle powered by both battery and gasoline (PETROL). The combination of both the power makes the vehicle dynamic in nature over conventional automobiles. Hybrid electric vehicles combine an electric motor, battery and power system with an internal combustion engine to achieve better fuel economy and reduce toxic emissions. Equipment and their cost analysis are done. It deals with the fabrication of the vehicle. The final stage would consist of increasing the efficiency of the vehicle in economic ways.

A 3-D two-fluid CFD model in the Eulerian-Eulerian framework was developed to predict the hydrodynamics and heat and mass transfer of sieve trays. Interaction between the two phases occurs via interphase momentum and heat and mass transfer. The tray geometries are ...

This paper considers the age of air in a ventilated space with multiple supply inlets; the local mean age (LMA) of air is different from one inlet to another in multiple supply inlet situations. The purpose of this paper is to investigate theoretically the relations between the LMAs arising from each supply inlet and the overall combined LMA for all inlets. Transient concentration distributions are calculated using a CFD package in a simple room configuration with two inlets and one outlet, to verify the relations. Tracer gases are injected with a step-up method at each supply inlet individually, and at both inlets simultaneously. As a result, it can be found that the steady state concentration, with a continuous tracer injection at each supply inlet, works as a weighting factor for the corresponding LMA in calculating the overall combined LMA for the multiple inlet situations.

The main intent of this work is to simulate the aerodynamic effects on different configuration of commercial and delta wing at different angle of attack. This investigation aims to suggest a better aerodynamic configuration for wing to reduce the induced drag formed on wing during flight operation and in-turn improves the efficiency of the UAV. Simulation processes of computational fluid dynamic (CFD) on wing models for medium size high speed UAV, using typical section as NACA 2412 airfoil is been carried out at 1⁰, 2⁰ and 4⁰ twist angle. The twist is provided to adjust pressure distribution henceforth lift distribution along the wing. ANSYS Fluent is used to analyze the pressure distribution on the surface of wing at speed of 0.6 Mach. The lift and drag forces are also determined which were used for calculating the coefficients of lift and drag. The obtained results were used to establish a comparison between aerodynamic performances of all provided models.

The thermal performance of a natural draft dry cooling tower (NDDCT) under a crosswind has been investigated using a general-purpose CFD code. A three-dimensional study using the standard k–ε turbulence model to simulate airflow in and around an NDDCT has been conducted. A parametric study has been carried out to examine the effect of crosswind velocity profile and air dry-bulb temperature on the thermal performance of an NDDCT. Two approaches have been considered in this study to quantify the crosswind effect. Firstly, simulations have been conducted at the nominal conditions and crosswind effect has been represented by thermal effectiveness parameter. Secondly, the ejected heat from the NDDCT has been maintained at a constant value (285 MW) and the crosswind effect has been represented by the change in the cooling tower approach parameter. After quantifying the effect of the crosswind on the thermal performance, windbreak walls have been introduced as a means of reducing this effect. The results in this paper show the importance of considering the crosswind velocity profile. Moreover, the introduction of windbreak walls has indicated an improvement in reducing the thermal performance losses due to the crosswind. Copyright © 2004 John Wiley & Sons, Ltd.

The object moving at high speeds encounter forces which tend to decelerate the objects. This resistance in the medium is termed as drag which is one of the major concerns while designing high speed aircrafts. Another key factor which influences the design is the air drag. The main challenges faced by aerospace industries is to design the shape of nose cone of flying object that travels at high speeds with optimum values of air drag. This study deals with computational analysis on elliptical nose cone profiles of a commercial aircraft. The effect of nose shape on the drag is studied at subsonic flow with Mach 0.3.The scope of this paper is to develop some prototype profiles with outstanding aerodynamic qualities and low cost for use in construction projects for aircrafts increasing their efficiency and effect on target. The motivation for such a work is caused by lack of data on aerodynamics for profile of elliptical nose cone and especially improved aerodynamic qualities that can be used in designing aircrafts. Flow phenomena observed in numerical simulations for different AOA for elliptical nose cone profile are highlighted, critical design aspects and performance characteristics of selected nose cone are presented.

In this paper we present a methodology for adjustment of subsonic compensation characteristics of an aerodynamic-compensation Pitot tube. This methodology is based on manipulation of a Pitot tube profile (shape) downstream of the static pressure port such that its subsonic characteristics are modified while the supersonic characteristics remain unchanged. Due to this “rear-body” shape adjustment, complete redesign of a developed or in service Pitot tube is not required. We have used computational fluid dynamics tools in the analysis and design refinement of a Pitot tube by rear-body shape adjustment. The complete Mach number regime (M<2) has been computationally analyzed for three different rear-body profiles. The results of our study indicate that significant variation in subsonic compensation characteristics of a Pitot tube is possible by this method.

The performance of heat exchangers, for single-phase flows in particular, can be improved by many active and passive augmentation techniques. One such passive augmentation technique used for analysis this paper is vortex generation with the help of twisted tapes. An experimental analysis is carried out on a plain tube and tube with twisted tape under different mass flow rates and heat flux. A tube of 48mm diameter and 400mm length was taken for the experiment and a twisted tape of twist ratio yw=9.09 and thickness 2mm with 400mm length was inserted in the tube. Air supplied through the tube was heated up by the band heater. Temperatures of the air at different sections were recorded with the help of thermocouples. These experimental results are then compared with the numerical model for validation. A parametric study is carried out of different twist ratios of twisted tapes on temperature distribution of air at different section of the tube along its length. Three different twist ratios were considered 9.09, 6.05 and 3.64. Among these it was found that the twisted tapes with 3.64 gave an improved heat transfer as compared to other two twist ratios as well as the plain tube.

Propellers are responsible for the altitude and attitude motions of a Quadcopter type of unmanned aerial vehicles (UAV). A propeller generates the thrust in the axial direction of the propeller's rotation. In the present study, the computational fluid dynamics (CFD) analysis has been performed on a Quadcopter and its propeller to calculate the thrust generated by the propeller under the applied rotational speed. The solid CAD models of a Quadcopter and propeller have been designed in Catia v5. The created propeller design has been imported to ANSYS workbench fluid flow (fluent) module. Simulation has been conducted by using the k-epsilon turbulence model. Furthermore, the obtained results have been imported from fluent flow module to transient structural module in order to find out the deformation and stress induced in the propeller, due to the pressure generated by the rotation of propeller at 6500 RPM. From the obtained results, it can be seen that the designed propeller can generate the required amount of thrust force to lift the Quadcopter and can sustain the dynamic loading without failure.

In this paper, a set of potential hydrocyclone designs are explored for fines classification using Computational Fluid Dynamics (CFD) technique. The CFD model uses Volume of Fluid multiphase model coupled with Reynolds Stress turbulence model for two phase flow predictions. Lagrangian Particle Tracking and Algebraic Slip Mixture model (ASM) modified with shear lift forces and slurry rheology corrected with fines fraction are used to predict the particle classification. Conventional cylindrical-conical design and various novel cyclone designs having a combination of multiple and small cone angles, tapered vortex finder and air core free designs are considered in this study. Simulation results are presented in terms of mean and turbulent flow field along with particle efficiency curve. Predictions show that all the tested novel designs are inherently having the potential for finer cut separation and higher tangential velocity compared to the conventional design. Cyclone design with a small cone angle is further modified by placing various sizes of rods at the center axis of the cyclone. Multiphase simulations with modified ASM model are also carried out for the multiple cone angles design, standard design, and the modified small cone angle design with full length rod at 15 wt% of solids. Performance by multiphase simulations show that multiple cone angles design and modified small cone angle design with the full length rod are the best among the tested designs yielding high separation efficiency, smaller cut-point and minimum coarse particle misplacement due to resultant turbulence minimization.