油冷モータコイルエンドを模した角柱群における油流れ解析の基礎研究

抄録

An oil-cooling method is often used for electric vehicle motors, in which oil is directly sprayed onto motor coil ends. Computational fluid dynamics (CFD) is utilized in the research and development processes of the oil-cooling system, but the accuracy has not been quantitatively verified because of the high Prandtl number flow with the free surface of the oil. Another reason is that the coil end, in which copper wires are bundled, has some complicated structures and many narrow gaps, making it difficult to confirm and comprehend the oil flow quantitatively. In this study, acrylic rectangular columns with gaps imitating oil-cooling motor coil end were created, and visualization experiments of how dropped oil flows on the side of columns and through the gaps were conducted. The simulations using the particle-based and finite volume methods were performed and compared with the experiments. On the side of the columns, the particle-base method well reproduced oil flow, while there was no flow in the finite volume method. In the gaps, both CFD methods reproduced the same qualitative flow. In the gap of the upper column near the dropping point, the flow simulated by both CFD methods were faster than those in the experiment.