Papers by Keyword: CFD

Abstract: In recent years, as the automotive industry is growing, one of the major hope for future vehicles is to meet emissions regulations. Automobiles pollute the air, and clean-air laws have made Catalytic Converters a legal requirement because they convert harmful pollutants from an engine's exhaust into cleaner emissions. The device works with the principle of a catalyst, something that causes or speeds up a chemical reaction without itself being changed. But the presence of a catalytic converter increases the exhaust back pressure which has an indirect effect on the engine efficiency ie engine efficiency decreases, thus increasing fuel consumption. The performance of a catalytic converter is substantially affected by the flow distribution inside the substrate, a uniform flow distribution can increase its efficiency, lower the pressure drop and optimize engine performance. The flow distribution in a catalytic converter assembly 15 is governed by the geometry configurations of the inlet and outlet cone section, the substrate, and exhaust gas compositions, and therefore a better design of the catalytic converter is very important. This Project deals with the fundamental understanding and study of complex processes taking place involving fluid flow, pressure, and velocity profiles in the catalytic converter using ANSYS WORKBENCH 2022 R1. The main objective of our analysis is to determine the most effective and optimum design of a Catalytic Converter

Abstract: This study analyses physical aspects of power-law fluid flow over a diamond shaped cylinder under the impact of a movable screen fixed in the middle of a channel keeping an aspect ratio as 0.5 with height of the channel. The perforated plate is a screen at the middle especially settled at orientation of π/6, π/4 or π/3 degrees. The Reynolds number (Re) has been kept in the range of 1000-10,000 with power-law index in the range 0.8-1.2. For the corresponding two-dimensional problem, the governing momentum equations coupled with energy equation have been solved numerically using non-isothermal laminar fluid flow interface in the software COMSOL Multiphysics 5.4. The dimensionless velocity magnitude and the non-dimensional temperature on the diamond shaped cylinder along the vertical non-dimensional length are expressed via fixing any two parameters from (Re), angle of screen θ and power-law index. The heat transfer coefficient, effective thermal conductivity and the Nusselt number are also expressed besides the dimonsionless length of the surface of the chosen cylinder. In conclusion, we will be going to suggest points to increase the dynamics and thermal variables with the use of selected parameters Re, θ, and power law index n.

Abstract: Semisolid materials with a non-dendritic microstructure have a complex rheological behavior such as pseudo-plasticity and thixotropy. These properties affect filling and solidification processes during, casting; thus, simulation plays a vital role since it avoids limitations improving cast and production performance. In order to study and A356 aluminum semisolid alloy flow, a Computational Fluid Dynamics (CFD) software (ANSYS) is used to simulate the die filling process in a rectangular mold. Three non-Newtonian constitutive equations are modeled in this work: the Cross equation, the Power-law equation and the Carreau equation. The rheological parameters for each equation were obtained from experimental data reported in the literature. The results showed that the non-Newtonian models predicted better the filling behavior and the pressure distribution than the Newtonian model.

Abstract: One of the most complex issues that govern the design of a hypersonic vehicle is aerodynamic heating which is much more severe for an air-breathing vehicle as it operates within the atmosphere for longer durations. Due to the detrimental impact of aerodynamic heating on the vehicle structure, it is imperative to develop a robust thermal protection system that can protect the vehicle from high temperatures. However, the development of sophisticated TPS for slender components is impractical and, therefore, requires a hot structure system that can operate at substantial aerothermal loads. The aim of this study is to predict the impact of aero-heating on a UHTCC-based hot structure system of a hypersonic cruise vehicle through uncoupled thermo-structural analysis of the control surface. Validation of numerical methods implemented is done through literature comparison and grid independency tests.

Abstract: Covid-19 is a highly contagious aero-transmissible virus. Even after two years of its emergence, new strains appear that require strengthening security measures such as social distancing, the use of masks, etc. It is crucial to prevent contamination, and care for the sanity of the air in closed environments, occupied by two or more people. Aerosols expelled by contaminated individuals dissolve in environments and can contaminate individuals regardless of their location. In this project, an air purifier for individual use was proposed to mitigate the risk of contamination by Covid-19 in closed environments. The equipment has been developed and prototyped, but has yet to be presented in the scope of this article. In this phase of the project, a study was conducted through numerical simulation to understand the effect of using this purifier on air circulation and its scope in the environment. Nine scenarios were developed: five two-dimensional and four three-dimensional, subject to different conditions: (i) closed environment, (ii) air infiltration through doors and windows, (iii) air-conditioner use, and purifier use. In individual use of the purifier, even if it is approximately 50 cm from the person in the room, the curtain of “clean air” coming from the purifier has become ineffective due to the existence of another, more intense outlet. The scenario with the airflow from the air-conditioner showed that the higher intensity of the airflow compared to the prototype purifier's airflow, meant that the prototype's airflow could not protect the user from the theoretically contaminated air mixed in the room. When the simulation of the use of the purifier was not done together with the air-conditioner runoff, the purifier proved effective in providing clean air and "protecting" the user with a wind curtain. However, even when the purified air cannot directly protect the user, the effects of the purifier can be beneficial by reducing the contamination of the air in the room as a whole (with a flow rate of 0.016 m3/s or 57.6 m3/h), and potentially reducing the chances of virus infection.

Abstract: The data center industry consumes between 196 and 400 terawatt-hours annually, between 1% and 2% of the world's energy consumption. A high percentage of data center energy consumption is associated with air conditioning and cooling systems. The optimization of the data center cooling process can occur at multiple scales, being one of the most relevant to the generation and heat transfer processes within servers. In this approach, we must study the temperature fields of each server’s components and understand airflow behavior within the server chassis. The present work, in its first stage, performs a thermal and cooling analysis for a two-unit rack server (2U-Rack) using computational fluid dynamics (CFD) techniques via Ansys Fluent code. A geometric server model was developed, considering heat generation in the main electrical components and heat and air mass transfer with the data center. The model was validated by comparing simulation results with the server's sensor values and the results of thermography testing. Following CFD simulation, airflow velocity fields, temperature contours, and sensitivity scenarios were obtained, with the goal of proposing an optimization model that would allow us to improve server heat transfer processes in the following steps.

Abstract: Commercial buildings are high energy consumption buildings due to lighting system, cooling, and heating requirements (HVAC) for main corridors, shops, and other services. This research is offering an innovative environmental solution for one floor existing commercial buildings by retrofitting the design to be naturally ventilated which lead to reduce building energy consumption and Co2 production. This Research main concept is ventilating corridors and common spaces at one-floor commercial building naturally and achieving users’ thermal comfort even in the hottest day at summer.Research case study is one-floor existing commercial building in Ras El Bar, Egypt. Building model is constructed in Design Builder software to simulate building energy consumption in the current design as base case and compare different environmental solutions results with it to estimate the energy and Co2 reduction. Also, CFD simulation for different design proposals is simulated to guarantee comfort natural air flow inside the corridors for building users.In addition to visit to building site to measure temperature and wind speed by multi-functional anemometer in many focal points indoor and outdoor the building, to consider any missing data that could affect on the final decision.Finally, after simulating more than one solution, the study present solution that naturally ventilate the on-floor commercial building and achieved users’ thermal comfort at summer.

Abstract: The purpose of this research is to better understand the characteristics of two-phase flow in a rectangular bubble column. Computational Fluid Dynamics (CFD) (ANSYS-FLUENT R15.0®) has been used to conduct numerical studies of the flow pattern. Furthermore, the experimental data is used to verify the accuracy of the numerical data. This unique CFD simulation research included a 3D system, Reynolds-Average, Navier-Stokes equations (RANS), k-turbulence model, and total interphase forces. Bulk flow patterns were revealed through CFD analysis. Total contact force, both constant and non-steady, is also analyzed for its impact. The data show liquid upflow in the column's bulk section and liquid downflow near the wall. In the gas phase, bubbles rose in the middle area and departed the bed. In addition, bubbles without enough velocity to leave the bed circulate towards the wall with liquid and follow a similar pattern. The results show that the phenomenon of the central peak can only be captured by using a single bubble and no drag forces. The correlation between simulation and experimental findings is excellent. Within the higher, middle, and nearby gas distributor height ranges, the outcome agrees extremely well with the experiment. In addition, the results of the experiments show that the level of turbulence has played a crucial role in dynamic behavior. The CFD model described qualitative and quantitative flow performance, producing excellent results. The results also gave a framework for comparing and evaluating future designs and gave insights into the fluid dynamics of the bubble column reactor. Efforts were made to compare and contrast the main operating modes of different reactor designs. Keywords: Two phase, Ansys, Bubble column, CFD, Drag force, Flow Pattern.

Abstract: The present paper focuses on the effect of geometric shape of a cylindrical body submerged in an oscillating flow by means of numerical investigations. The cylindrical body has an elliptic cross-section with a variation of its elliptic ratio (ratio between major and minor axes of the elliptic section). The flow direction is oriented along the major axis. Three regimes from (Tatstuno and Bearman) maps are studied namely, a symmetric regime A and two other asymmetric regimes D and F. The flow field structures, the Morison coefficients of longitudinal forces and the root mean square (r.m.s.) of transverse forces are computed with respect to the elliptic ratio variation. For the case of cylinders with slightly elliptic cross-section, vortices and pressure fields are very similar to those of a circular cylinder. For the case of regime A, the vortex shedding is always symmetric despite the unbreakable variation of the elliptic ratio. On the other hand, the reduction of the elliptic ratio weakens the asymmetry of the flow for regimes D and F. Moreover, the flow in each regime becomes completely symmetric at a given value of the elliptic ratio. In fact, the predicted longitudinal component of the force acting on the cylinder decreases with the reduction of this ratio. This results in the same manner on the behavior of Morison coefficients. With regard to the symmetric regime A, the transverse force does not manifest itself for all considered ratios. On the other hand, the transverse force in the case of asymmetric regimes decreases rapidly with increasing the ellipticity of the cylinder. The present study showed us that the inertia coefficient is sensitive to the vortex path; however, the drag coefficient is independent of the vortex path. Both coefficients depend simultaneously on Reynolds number and the geometric shape of the body.

Abstract: We try through this research to present a detailed study on free convection heat transfer inside a closed space. The work is carried out in numerical way, using the method called finite volume. The governing equations are solved for numerical simulations of steady state and laminar regime. The studied domain is an annular space consisting mainly of two cylinders positioned horizontally, the inner cylinder has an elliptical shape with different aspect ratio (E) while the outer one has a single shape which is circular. The primary conditions adopted in this research are as follow: the outer cylinder has a cold surface, while the inner cylinder has a cold surface. The space between cylinders is considered to be filled with fluid of different values of thermo-physical proprieties (Pr). The fluid in the space moves under the influence of thermal buoyancy which is controlled by Ri number. The pertinent parameters for this research are: the aspect ratio of elliptical cylinder which is E = 0.1 to 1, the Prandtl number Pr = 1 to 100 and finally the Richardson number Ri = 10³, 10⁴ and 10⁵. The results of this work show that the elliptical form allows an increase in thermal transfer activity. Also, values of the number Pr have a limited effect on heat transfer.