Coupling Simulation Analysis on Support System of High-energy Storage Flywheel System

Abstract

A 3D model of the upper and lower support were established via ANSYS WORKBENCH14 on the basis of a new cooling system and both temperature and stress of different materials coupling simulation analysis have been done. The result shows that: One of the best choices of the material of the supports were copper alloy, which has a little impact on the thermal stress of the whole system. The heat generated from the bearing and motor can be removed by using the proposed cooling system timely so that the temperature of the flywheel system can be maintained in a normal range. Keywords-High-energy storage flywheel system;Support system;Coupling simulation As the high-energy storage flywheel system produces heat loss in the precedure of store-release energy, the design of the cooling system becomes one of the key techniques in the engineering application of the high energy storage flywheel system. Common cooling model nowadays includes circulating water cooling system, air cooling system, and heat sink cooling system, etc [1]. Although circulating water cooling system performs better than air cooling system, its equipment has many defects, such as the complexity and leakiness, which make it very difficult to manage. Moreover, convection in vacuum is negligible. The cooling effect can be achieved effectively by using conduction. I THE DESIGN OF COOLING SYSTEM Taking into account safety issue, the high-energy storage flywheel system is usually set in underground. The performance of cooling system depends on thermal conductivity of the soil, which is closely linked with the heating part, while, the thermal conductivity of the soil is very poor. The heat through the support with high heat conduction performance will transfer to the cylinder body of the vacuum chamber, and finally achieve the ground via the cylinder which is coupled with the high-performance components. Fins are added at the part on the ground to ensure that temperature of the support system is stable. The structure of cooling system is shown in Fig. 1. Fig. 1 Structure of cooling system 1.upper support; 2.lower support; 3.the cylinder body; 4.thermal coupling element; 5.high-performance components ; 6.fin II THE SIMULATION AND ANALYSIS OF COOLING COMPONENTS The sources of heat production for the high-energy storage flywheel system are 1, the friction of mechanical bearing; 2, the coil of electromagnetic bearing; 3, the iron loss and copper loss of permanent magnet brushless motor. The position of the parts are on the upper and lower support. Due to the actual situation, the coupling simulation analysis on both temperature and stress of different materials were doing respectively. It is hard to obtain the results through the analytic way for this kind of coupling problem, so numerical calculation way, by using the convection conduction coupled simplified mode, should be used to accomplish this problem. A Hypothesis These hypothesis have been used through the process as follows, (1) ignore the thermal contact resistance;(2)ignore the radiation and convection of the internal surface;(3)the air is constant property;(4)the high performance heat conduction component is equivalent to the same geometric size metal rod with excellent thermal conductive performance. Based on the classic theory such as the principle of conservation of energy, the Fourier law, Newton cooling formula, the finite element analysis software was used during the process of this analysis. Proceedings of 2012 International Conference on Mechanical Engineering and Material Science (MEMS 2012) © 2012. The authors Published by Atlantis Press 277 B The finite element method and the solution of governing equation Based on the classic theory[3] such as the principle of conservation of energy, the Fourier law, Newton cooling formula, the governing equation of heat transfer problem was deduced as follows t T c Q z T k z y T k y x T k x T z y x            