著者

福田 悠太 細井 裕貴 片山 雄介 渡邉 聡 津田 伸一 森 義英

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会九州支部講演論文集

巻号頁・発行日

vol.2019, 2019

---

<p>Cavitation phenomenon in automotive torque converter causes various problems such as erosion, noise and performance deterioration. In this study, the mechanisms of cavitation occurrence and its effect on the torque converter performance are discussed by experiment and numerical analysis. It is found that the inception cavitation number decreases as the speed ratio increases and is less influenced by the pump rotational speed. Since the cavitation locally occurs at the inception condition and the local minimum pressure coefficient obtained by the numerical analysis well correlates with the incipient cavitation number, the cavitation inception based on the naked-eye observation is found to be not significantly influenced by the dissolved air. On the other hand, the performance degradation is found to be strongly affected by the amount of dissolved air. Many bubbles are observed in the whole flow passage at this condition. Since the averaged pressure inside the torque converter flow passage well correlates with the gas equilibrium pressure in the high dissolved air condition, it is found that the density decrease due to the huge amount of gas bubble generation deteriorates the performance of torque converter. However, at low dissolved air condition, the above correlation does not well hold, which seems to indicate that the performance degradation is caused by the local vaporous cavitation.</p>