Multi-stage Hydraulic Machinery Interior Flow Field Numerical Analysis Research

At present, regarding on hydraulic machinery which contains many impeller, like torque converter, because of impeller's mutual influence and its complex internal flowing, it is difficult to carry on the numerical simulation accurately. This article uses the CFD technology, studies the reasonable computational method, namely using the computational method and the mix plane law together, has carried on the numerical simulation to its three dimensional flow field, calculating the speed of flow and the pressure distribution precisely, has also carried on a thorough analysis to impeller's fluid state and forecasted its operational factor accurately.This article takes the YB355-2 torque converter as the object. The research indicated that when using piecemeal computed result to establish reasonable initial flow field and using the mix plane law to computate torque converter's interior flow field, may enhance the computation convergence and accuracy rate, is also advantageous in analyzing torque converter's interior flowing characteristic and computating accurately about various impellers and the whole performance. The results have certain important meaning to improve water frame's design method and enhance the multistage hydraulic machinery 's performance.This article mainly divides into three major parts:The first part: Introduced about domestic and foreign research present situation on torque converter and the hydromechanics computation method, proposed research content and introduced the hydraulic machinery numerical calculus theory method.The second part: Using the piecemeal computation method and the mix plane computation law together, carried on the numerical simulation computation to the YB355-2 torque converter's ten operating point's internal flow fields; using the numerical calculus result, analyzed gear ratio (i=0 and i=0.69) under typical operating mode various impellers' operational factor.The third part: Using the numerical calculus result, analyzed gear ratio (i=0 and i=0.69) under a typical operating mode various impellers' flow field characteristic, also analyzed various leaf blades chord surface, the air-foil, the festival surface speed and the pressure distribution, observed the secondary flow which appears on the different surface.This article uses more reasonable computational method to enhance its computational accuracy and has carried on the numerical calculus to the YB355-2 torque converter's internal flow field. The research results have vital significance to improve the multistage hydraulic machinery's design method and to enhance its performance characteristic.