著者

湯淺 朋久 阿部 豊 平野 覚

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.856, pp.17-00309-17-00309, 2017 (Released:2017-12-25)

参考文献数

17

被引用文献数

2

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Toward the improvement of performance of the electric vehicle (EV), the design of the motor shape appropriate to heat removal is important. A typical EV motor is composed of a pair of coaxial cylinders with a fixed outer cylinder (stator) and a rotating inner cylinder (rotor). Some EV motors have axial slits on the stator wall. The present study numerically clarifies the physical mechanism of difference of Nusselt number between the case with slit and without slit. The heat transfer of the gap between the rotor and stator was obtained by the numerical calculation. A vortex structure observed by flow visualization experiment was reproduced in the numerical simulation, and velocity profiles showed good agreement with experimental data. The heat transfer rate for the case with slit in the high rotational speed was increased compared with that for the case without slit. Nusselt number was decomposed into the three terms which were the advection, turbulent transport and diffusion terms; the advection term of heat flux for the case with slit was increased compared with that for the case without slit because of the vortex structure. The Nusselt number on the slit surface was increased compared with that on the gap surface for the case with slit. It was implied that the difference of Nusselt number between the case with slit and without slit was caused by the presence of the vortex structure in the slit and the increase of heat flux for the case with slit.

著者

湯淺 朋久 阿部 豊 平野 覚

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.849, pp.16-00551-16-00551, 2017 (Released:2017-05-25)

参考文献数

11

被引用文献数

2

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Toward the improvement of performance of an electric vehicle (EV), the design of the motor shape appropriate to heat removal is important. A typical EV motor is composed of a pair of coaxial cylinders with a fixed outer cylinder (stator) and a rotating inner cylinder (rotor). Some EV motors have axial slits on the stator wall. The present study experimentally clarifies the influence of inner shape on flow behavior in the EV motor. We divided the measurement area into three regions: the gap region, the rotor end region, and the gap end region. The flow behavior was recorded by a high-speed video camera and was measured via PIV. The flow behavior in the gap and rotor end regions were observed by Kalliroscope flakes. Taylor-Couette flow was observed in the gap region for the both cases without and with slits. In the rotor end region, the vortex that spirally flows from outer cylinder to the inside cylinder was observed. The white dye, injected in the gap, remained at the injection point for the cases without slits. However, the dye moved from the gap region to the rotor end region for the cases with slits. The vortex structure directed to the rotating axis was observed in the slit on the stator wall; the vortex had the axial velocity from the gap region to the rotor end region.