L10
Computational Fluid Dynamics 1

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08:35
conference time (CEST, Berlin)
Numerical and Experimental Investigation of Flow Through Water Filters Using Porous Media Approach
27/10/2021 08:35 conference time (CEST, Berlin)
Room: L
R. Kadam, A. Awachat, P. Deshmukh, P. Gandhi (Whirlpool Corporation, IND)
R. Kadam, A. Awachat, P. Deshmukh, P. Gandhi (Whirlpool Corporation, IND)
The aim of the present study is to estimate flow rate through water filters used in refrigerators at various inlet pressures through simulation. Regions of high pressure are identified and design modifications are also suggested to reduce the pressure drop. The baseline design of the water filter was tested in the laboratory and was used to validate the simulation results. As modelling the actual carbon block in simulation is complicated, a porous media approach was used to model the pressure drop through the carbon block of the water filter. Darcy-Forchheimer coefficients are calculated using the pressure drop vs. flow rate characteristics of the carbon block obtained from the manufacturer of the carbon block. For a range of various inlet pressures as per requirement, flow rate and total pressure drop are calculated. The mesh independence study was carried out and mesh size of ~ 2.4 million tetrahedral cells was found to be optimum and used for the final simulations. The commercial code of Ansys-Fluent 20R1 is used for meshing and simulating the problem. Flow rate estimated from simulation for baseline design is within 7% of test results. Regions of high pressure drop are identified - about 11% of the pressure drop is observed due to sharp turns in the baseline design. Suitable design modifications are suggested based on simulation results and simulations on the modified designs showed upto ~ 8% increase in flow rate through the water filter for the same inlet pressure. This study demonstrates the successful use of a porous media approach to estimate flow rate through water filters which matches test results with 7% of difference. Thereby modifying the filter design to improve the flow rate through the water filter is fully based on simulation results.
Porous media, Flow rate, Pressure drop, Viscous and Inertial Resistances
08:55
conference time (CEST, Berlin)
Discussion on the Development of 3D, Multiphase Solvers for Problems in Solid Rocket Propulsion
27/10/2021 08:55 conference time (CEST, Berlin)
Room: L
N. Srivastava, T. Jayachandran (Indian Institute of Technology Madras, IND)
N. Srivastava, T. Jayachandran (Indian Institute of Technology Madras, IND)
A discussion on the ongoing development of multiphase solvers for addressing computational problems in solid rocket propulsion will be presented. The working substances of solid rocket motors are typically non-homogenous and are comprised of multiple phases. Some of the combustion products condense into particles in the flow field while others are gaseous. As a result, the working substance is essentially a suspension of condensed combustion products (CCP) in hot gases. Due to this, a number of complex physical phenomena are introduced in the flow field inside the rocket, which cannot be visualized by using a simple single-phase Navier Stokes solver. Therefore, for realistically capturing the flow features in a rocket, a 3D multiphase flow solver is required. The ongoing work is aimed at developing and testing multiphase solvers which would be capable of predicting the flow features and performance parameters of solid rocket motors. A family of solvers is being developed which can capture the interaction of multiple phases. Here, the word "phase" denotes chemically or physically distinct substances which may need be be modelled separately. The solvers have been developed in FORTRAN. The spatial discretization of the governing equations has been done by using the unstructured finite volume method. The solvers have been developed for tetrahedral meshes. Integration in time is done using the explicit Range-Kutta 4 stage method. The Euler-Euler or Multi-fluid model for multiphase modelling is used. This model states that all "phases" in the flow can be approximated as interpenetrating continua and that the interactions between the phases can be modelled by the means of certain constitutive equations, such as that of fluid drag. The multiple components co-permeate in the domain as fluids, i.e., they're able to occupy the same space simultaneously. The objective of these solvers is to provide a means to estimate the thrust losses and salient flow features introduced by the multiphase nature of the flow field inside a solid rocket motor. However, the solvers developed are largely generic and may be adapted to several other multiphase problems by making minimal problem specific modifications. In this work, we intend to discuss the governing equations, constitutive equations and the models and methods used for the development of our solvers.
Multiphase, CFD, Rocket Propulsion
09:15
conference time (CEST, Berlin)
Prediction of Clogging of Detergent in Dispenser Using Computational Fluid Dynamics Simulation
27/10/2021 09:15 conference time (CEST, Berlin)
Room: L
A. Nagarajan, B. Shome, P. Dhanasegar, K. Parashar (Whirlpool, IND); Prof. S. S. Mujumdar, (Birla Institute of Technology & Science, Pilani, IND)
A. Nagarajan, B. Shome, P. Dhanasegar, K. Parashar (Whirlpool, IND); Prof. S. S. Mujumdar, (Birla Institute of Technology & Science, Pilani, IND)
The washing machine has become an integral part of our urban daily life. We have a vertical Axis washing machine (VA) and a Horizontal axis washing machine (HA) that are popular among the large portion of the customer using the washing machine. Year on year the expectation of the customers are raising in terms of the water usage and energy rating for running these machines. So it becomes of utmost importance to have a very efficient machine to wash our clothes with very less water as much as possible. While the machine cleans our clothes efficiently with the right amount of detergent, detergent dispensing in washing machines is a very critical step to determine the wash quality of the clothes. In today’s scenario, we have powder and liquid detergent used by everyone for washing the clothes in the washing machine. The amount of detergent getting dissolved with the water becomes more critical. The improper mixtures result in detergent residual in the dispenser and affecting the wash performance of the machine. This project aims to predict early in the design cycle, the performance of the complete dispenser assembly which includes powder/liquid detergent, softener, and bleach compartment by monitoring water flow using Computational Fluid Dynamics (CFD) methodology. In this paper, water flow distribution is studied for Softener and detergent chambers. Using the Euler-Euler approach with Volume of Fluid (VOF) method in Commercially available Ansys Fluent solver. This assessment shows the simulation prediction has a good correlation with the physical test results for the Softener chamber which extended for the detergent chamber also. Leveraging this prediction at an early stage of the design will help us to prevent detergent clogging in the detergent chamber and provide an optimized design of the dispenser. The study encompasses developing a guideline for the simulation by identifying the optimum design requirements for the nozzle location/shape for the detergent chamber to avoid clogging of the detergents in the dispenser and the amount of water flow required without splashing in the dispenser drawer which will not show in leakage of water. Simulation is useful to monitor critical zones prone to clogging/residual of detergent in the dispenser. Design optimization is based on water coverage and impinging velocity.
Keywords: CFD, Dispenser, Detergent, Simulation, VOF, Washing machine.
09:35
conference time (CEST, Berlin)
The Analytical and Numerical Model to Predict Low Reynold’s Number Pressure - Flow Characteristics of a Valve With Non-Linear Opening Boundaries
27/10/2021 09:35 conference time (CEST, Berlin)
Room: L
A. Gopinathan, C. Muraleedharan, D.V. Vipin, L.J. Sukanya (Sree Chitra Tirunal Institute for Medical Sciences and Technology, Bio Medical Technology Wing, Trivandrum IND)
A. Gopinathan, C. Muraleedharan, D.V. Vipin, L.J. Sukanya (Sree Chitra Tirunal Institute for Medical Sciences and Technology, Bio Medical Technology Wing, Trivandrum IND)
The valves have various medical and industrial applications where there is a requirement for flow control. The level of opening or opening deflection of the valve is either independent of the flow conditions or varies according to the inlet pressure depending on the type and application of the valve. The computation of Pressure drop - flow rate characteristics is essential as far as the design of a new valve or selection of a standard valve is considered. The flow across a valve at a certain level of opening is bounded by the valve closing plug surface (top boundary) and the surface of seating (bottom boundary) and the same have significant influence over the pressure drop across the valve for a particular flow rate. In this paper, a study was conducted to obtain an analytical model to obtain the pressure-flow characteristics which depend on the boundary profiles of the valve plug and seating and also on the fluid parameters like viscosity and density, the structural parameters like the stiffness of spring supporting which offers the resistance reaction to the inlet pressure force acting on the valve plug and the weight of the plug. The analytical model is in the form of an equation of Flow rate which included the parameters - Inlet Pressure, Viscosity, Radius of Valve seating, Valve plug profile parameters, Valve seating profile parameters, Stiffness of spring, Mass of Inlet Plug. What makes this analysis different is that it is particularly done for the nonlinear plug and seating profiles in which there could be considerable variation in flow directions at each level of opening of the valve. This calculation strategy ensures quick and accurate results ensuring the easiness in decision making while designing a valve for low Reynold's number application. The analysis was verified in Computation Fluid Dynamics based software and obtained close accuracy in result with a nominal error of 5% which proves the model to be a good benchmark for various experimental studies and applications which involves the low Reynold's number flow.
Valve Opening, Pressure drop, Pressure Flow Characteristics, Low Reynold’s number flow, Viscosity, Lubrication theory, Analytical analysis
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