Abstract
AbstractWith the development of electrical machines for achieving higher performance and smaller size, heat generation in electrical machines has also increased. Consequently, the temperature rise in electrical machines causes unexpected heating of components and makes it difficult to operate properly. Therefore, in the development of electrical machines, the accurate evaluation of temperature increase is important. In the thermal design of electrical machines, heat-conduction analysis using the heat-transfer boundary set on the surface of a heated target has been frequently performed. However, because the heat-transfer coefficient is dependent on various factors, it is often determined based on experimental or numerical simulation results. Therefore, setting the heat-transfer coefficient to a constant value for the surface of the heated target degrades the analysis accuracy because the actual phenomenon cannot be modeled. To enhance the accuracy of the heat-transfer coefficient, the coupled electromagnetic field with heat-conduction analysis finite element method (FEM), thermal-fluid analysis using FEM, and the highly simplified marker and cell method is applied to the estimation of the distribution of the heat-transfer coefficient. Moreover, to accurately calculate the localized heat-transfer coefficient, the temperature distribution and flow velocity distribution around the heated target are analyzed in the induction-heating apparatus.
Highlights
In the development of electrical machines, components are placed with high density for high performance and miniaturization
“FE–FD” is defined as the coupled method in which the electromagnetic field is solved by finite element method (FEM), and heat conduction is solved by finite difference method (FDM)
“FE–FD–HS” is defined as the coupled method in which the electromagnetic field is solved by FEM, heat conduction is solved by FDM, and thermal-fluid analysis is solved by highly simplified MAC (HSMAC) method
Summary
In the development of electrical machines, components are placed with high density for high performance and miniaturization. As a simulation technique to evaluate the temperature rise in the actual driving state of electrical machines, coupled electromagnetic-field and heatconduction analysis using the heat-transfer boundary set on the surface of the heated target has been frequently carried out [1,2]. Evaluation of localized heat transfer coefficient for IH apparatus 505 the Lagrange coordinate system [5,6] is applied; the physical quantity of only the position where the particle exists is calculated. The behavior of natural convection derived from the induction heating phenomenon is simulated by the coupled electromagnetic-field with heat conduction and thermal-fluid analysis using FEM and HSMAC method. The evaluation method of the local heat-transfer coefficient [11] using the HSMAC method is demonstrated by comparison with actual measurements and numerical results
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