ELECTRIC FIELD SIMULATION

Electric Field Simulation



Electric Field Simulation

Task 1

Use Comsol Multiphysics to calculate the electric potential and electric field strength distribution between the electrode arrays.

In this paper, a multiphysics analysis of a high-speed PM machine is performed using the COMSOL Multiphysics commercial software. The heat transfer and CFD modelling are performed simultaneously using a 2D axi-symmetric model of the machine. The final results for the temperature distribution in the solid domain of the machine are obtained using a 3D finite-element heat-transfer model. The results from the aforementioned numerical methods are validated using the traditional thermal-network method which is widely used and experimentally validated. For that purpose, a thermal-network model for the considered machine is created. The results for the temperature distribution from the numerical methods are very close when compared with the results obtained from the thermal-network method although the two methods are based on two completely different approaches.

Fig. 1. Finite element mesh of the 2D geometry of the high-speed PM machine

The multiphysics method couples the equations from CFD and heat transfer so it gives a solution for the temperature distribution in the solid and fluid domains of the machine. A result of that temperature distribution is presented. The temperature distribution in the solid and fluid domains is not symmetrical. The temperature rise of the outlet side (the top of the figure) is higher than the temperature rise of the inlet side (the bottom of the figure).

Fig. 4. Distribution of the temperature rise ?T [K] in the solid and fluid domains of the electrical machine. The inlet side is on the bottom and the outlet side is on the top of the figure.

An accurate measurement of the temperatures in a high-speed PM machine is very difficult since the rotor is rotating in operation (would require a telemetry unit). That is why reliable theoretical methods for accurate prediction of the temperature distribution in the whole machine domain should be developed. In this paper, a combined 2D-3D finite-element thermal analysis of the electrical machine is presented. First, using a 2D multiphysics method, the thermal properties of the flow such as the coefficient of thermal convection and temperature rise of the flow were estimated. The distribution of the temperature rise in the whole solid domain of the machine was determined by the 3D numerical heat-transfer method. The results for the temperature rises in the machine from the aforementioned methods are compared with the results obtained by the thermal-network method that uses a totally different approach in the heat-transfer analysis. The presented numerical method is a novel compromise between the 2D axi-symmetric multiphysics rough modelling and the 3D thermal fine modelling, a compromise that allows an accurate estimation of the local temperature rises with a minimum amount of computational resources.

Simulation of the electric field

This section deals with the simulation of the electric field alone without considering fluid flow and the temperature distribution in the chamber. As a consequence, the effect of temperature on the electrical properties such as conductivity or dielectric permittivity cannot be considered, so ...