scholarly journals Modelling and simulation of heat conduction in 1-D polar spherical coordinates using control volume-based finite difference method

2016 ◽  
Vol 26 (1) ◽  
pp. 2-17 ◽  
Author(s):  
Attila Diószegi ◽  
Éva Diószegi ◽  
Judit Tóth ◽  
József Tamás Svidró
Keyword(s):  
Finite Difference ◽  
Finite Difference Method ◽  
Coordinate System ◽  
Heat Transport ◽  
Difference Method ◽  
Control Volume ◽  
Polar Coordinate System ◽  
Heat Absorption ◽  
Content Type ◽  
Polar Coordinate

Purpose – The purpose of this paper is to obtain a finite difference method (FDM) solution using control volume for heat transport by conduction and the heat absorption by the enthalpy model in the sand mixture used in casting manufacturing processes. A mixture of sand and different chemicals (binders) is used as moulding materials in the casting processes. The presence of various compounds in the system improve the complexity of the heat transport due to the heat absorption as the binders are decomposing and transformed into gaseous products due to significant heat shock. Design/methodology/approach – The geometrical domain were defined in a 1D polar coordinate system and adapted for numerical simulation according to the control volume-based FDM. The simulation results were validated by comparison to the temperature measurements under laboratory conditions as the sand mould mixture was heated by interacting with a liquid alloy. Findings – Results of validation and simulation methods were about high correspondence, the numerical method presented in this paper is accurate and has significant potential in the simulation of casting processes. Originality/value – Both numerical solution (definition of geometrical domain in 1D polar coordinate system) and verification method presented in this paper are state-of-the-art in their kinds and present high scientific value especially regarding to the topic of numerical modelling of heat flow and foundry technology.

An implementation of adjoint-based topology optimization in magnetostatics

2019 ◽  
Vol 38 (3) ◽  
pp. 1023-1035 ◽  
Author(s):  
Rtimi Youness ◽  
Frederic Messine
Keyword(s):  
Topology Optimization ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Difference Method ◽  
Design Problem ◽  
Large Scale ◽  
Adjoint Method ◽  
Processing Unit ◽  
Original Design ◽  
Content Type

Purpose In magnetostatics, topology optimization (TO) addresses the problem of finding the distributions of both current densities and ferromagnetic materials to comply with fixed magnetic specifications. The purpose of this paper is to develop TO in order to design Hall-effect Thrusters (HETs). Design/methodology/approach In fact, TO problems are known to be large-scale optimization problems. The authors therefore adopt the adjoint method to reduce the computation time required to obtain the gradient information. In this paper, they illustrate the continuous variant of the adjoint method in the context of magnetostatics TO. Herein, the authors propose an implementation of the adjoint method then use it within a gradient-based optimization solver fmincon-MATLAB to solve a HET TO design problem. Findings By comparison with finite difference method, the authors validate the accuracy of the suggested implementation of the adjoint method. Then, they solve a large-scale HET TO design problem. The resultant design of TO is distinctly original and not intuitive. Research limitations/implications In this paper, the authors introduce TO as a tool that has allowed them to explore new and innovative design of a HET. However, although the design presented is original, its manufacture is not feasible. Thus, a discussion section has been included at the end of paper to suggest a possible way to concretize topological solutions. Practical implications TO helps to explore more original design possibilities. In this paper, the authors present an implementation of the adjoint method that makes it possible to solve efficiently and in less central processing unit time large-scale TO design problem. Originality/value An easy implementation of the adjoint method is presented in magnetostatics TO. This implementation was first validated by comparison with the finite difference method and then used to solve a large-scale design problem. The result of the TO design problem is distinctly original and non-intuitive.

Reduced order field-circuit modeling of squirrel cage induction machines for automotive applications

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Dániel Bíró ◽  
Franz Diwoky ◽  
Erich Schmidt
Keyword(s):  
Simulation Model ◽  
Coordinate System ◽  
Induction Machines ◽  
Polar Coordinate System ◽  
Model Quality ◽  
Content Type ◽  
Reduced Order ◽  
Time Stepping ◽  
Squirrel Cage ◽  
Polar Coordinate

Purpose The aim of the paper is to investigate the impacts of simplifications of a reduced-order simulation model of squirrel cage induction machines (SCIMs) by numerical experiments. Design/methodology/approach Design of setups to isolate the main influences on the results of the reduced-order model of SCIMs. Results of time-stepping finite element calculations are used as benchmark. Findings Whereas neglecting eddy current effects and the assumption of a sinusoidal rotor current distribution leads to acceptable deviations in regular inverter operation, the sampling and interpolation of the machine parameters in a two-axis coordinate system considerably deteriorate the model accuracy. Using a polar coordinate system for this purpose is expected to significantly improve the model quality. Originality/value Preparing the ground for a successful, both fast and accurate simulation model of SCIMs as parts of electrified drivetrains.

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