The Cavitation Research Of The Flow Field In The Hydraulic Torque Converter Based On CFD

Torque converter has the advantages of good adaptability, stepless speed change and vibration absorbing buffer. It is the hydraulic transmission machinery in the core parts, which had been widely used in engineering machinery in recent years. The flow state is very complicated in the working process of hydraulic torque converter. Eddies in the flow field are very easy to occur, because of the larger pressure difference, the temperature gradient and the existence of turbulent. Cavitation is bound to cause vibration and noise, impacts on the stability of the entire hydraulic transmission system and can cause shorten the working life expectancy of the torque converter. It is necessary to study the cavitation and its mechanism of hydraulic torque converter. Through numerical calculation of the flow field, the conditions of cavitation are analyzed and studied, which can provide effective basis for avoiding or reducing the occurrence of cavitation and improving the performance and stability of the hydraulic torque converter.The research object of SD bulldozer hydraulic torque converter in this paper, the Pro/E 3D software is used to establish the model of the whole flow solid channel and the computational grid is partitioned by using tetrahedral unstructured grid technique in ICEM. Based on the FLUENT software, the three-dimens ional trans ient flow field of torque converter is simulated and analyzed, at the same time, mutual information transfer by sliding grid. The calculation is divided into two steps: 1.The analys is of the single-phase flow gasification and high inc idence of check and predict the final gasification zone, where the lowest pressure and the maximum temperature are tacking; 2.By using the VOF model in the multiphase flow, the bubble is implanted in the pump wheeland the simulation results are summed up, which are about of the single bubble flow path and the bubble rupture rule. So it reveal bubbles as the activation point of the hole, the release of the heat, causing the phenomenon of gasification. According to bubble annihilation principle to predict the occurrence of cavitation region, which can make contribution to design, improve the performance, provide a reference for further modification and optimization of torque converter.