With application of the lock-up clutch in the torque converter（TC）, fuel economy is not much determined by its high-speed ratio transmission efficiency. As a benefit, more researches are focused on its low-speed rat...With application of the lock-up clutch in the torque converter（TC）, fuel economy is not much determined by its high-speed ratio transmission efficiency. As a benefit, more researches are focused on its low-speed ratio performance so as to improve vehicle gradeability and launching acceleration performance. According to the results of computational fluid dynamics（CFD） analysis, hydrodynamic loss inside the stator cascade accounts for 42% of the total energy loss at stalling speed ratio. It is found that upstream flow with large impingement angle results in boundary layer separation at the leading edge, which aggregates hydrodynamic loss and decreases circular flow rate dramatically at low-speed ratio. In this paper, a dual-blade stator is proposed to suppress the boundary layer separation, which is parameterized by using the non-uniform rational B spline（NURBS） method. The mean camber line and blade profile curve are expressed by a three control points quadratic open NURBS and a cubic closed one respectively. The key design parameters included the slot width and suction side shape of the primary blade are analyzed. The most effective slot width is found to be between 4% and 8% chord length, and the boundary layer separation can be suppressed completely by decreasing distribution of momentum moment at the primary blade and adding it to the leading edge of the secondary blade. As a result, circular flow rate and impeller torque capacity is increased by 17.9% and 9.6% respectively at stalling speed ratio, meanwhile, low-speed ratio efficiency is also improved. Maximum efficiency at high-speed ratio decreases by 0.5%, which can be ignored as the work of lock-up clutch. This research focuses on using the dual-blade stator to optimize low-speed ratio performance of the TC, which is benefit to vehicle power performance.展开更多
Zhu Xi is a comprehensive synthesizer of Neo - Confucianism that developed during early Song Dynasty. Follow ing the meticulous spiritual direction of Cheng Yi,he has expanded the moral rationalism in the Song dynasty...Zhu Xi is a comprehensive synthesizer of Neo - Confucianism that developed during early Song Dynasty. Follow ing the meticulous spiritual direction of Cheng Yi,he has expanded the moral rationalism in the Song dynasty to the utmost. His strong group orientation leads him to attaching priority to normative rules and operative convenience,but his individual orientation leads him to seeking for the unrestrained poetic w ay of life. His pursuits of both the moral ideal of rationalism and the poetic life of romanticism result in his dual personality. He devoted all his life to the efforts to solve the conflict and tension betw een his dual pursuits,w hich provide an important clue for the profound understanding of the complexity of his philosophy.展开更多
基金Supported by National Natural Science Foundation of China(Grant No.51575393)
文摘With application of the lock-up clutch in the torque converter（TC）, fuel economy is not much determined by its high-speed ratio transmission efficiency. As a benefit, more researches are focused on its low-speed ratio performance so as to improve vehicle gradeability and launching acceleration performance. According to the results of computational fluid dynamics（CFD） analysis, hydrodynamic loss inside the stator cascade accounts for 42% of the total energy loss at stalling speed ratio. It is found that upstream flow with large impingement angle results in boundary layer separation at the leading edge, which aggregates hydrodynamic loss and decreases circular flow rate dramatically at low-speed ratio. In this paper, a dual-blade stator is proposed to suppress the boundary layer separation, which is parameterized by using the non-uniform rational B spline（NURBS） method. The mean camber line and blade profile curve are expressed by a three control points quadratic open NURBS and a cubic closed one respectively. The key design parameters included the slot width and suction side shape of the primary blade are analyzed. The most effective slot width is found to be between 4% and 8% chord length, and the boundary layer separation can be suppressed completely by decreasing distribution of momentum moment at the primary blade and adding it to the leading edge of the secondary blade. As a result, circular flow rate and impeller torque capacity is increased by 17.9% and 9.6% respectively at stalling speed ratio, meanwhile, low-speed ratio efficiency is also improved. Maximum efficiency at high-speed ratio decreases by 0.5%, which can be ignored as the work of lock-up clutch. This research focuses on using the dual-blade stator to optimize low-speed ratio performance of the TC, which is benefit to vehicle power performance.
基金sponsored by Shanghai Pujiang Program(12PJC028)Innovation Program of Shang-hai Municipal Education Commission(13ZS035)
文摘Zhu Xi is a comprehensive synthesizer of Neo - Confucianism that developed during early Song Dynasty. Follow ing the meticulous spiritual direction of Cheng Yi,he has expanded the moral rationalism in the Song dynasty to the utmost. His strong group orientation leads him to attaching priority to normative rules and operative convenience,but his individual orientation leads him to seeking for the unrestrained poetic w ay of life. His pursuits of both the moral ideal of rationalism and the poetic life of romanticism result in his dual personality. He devoted all his life to the efforts to solve the conflict and tension betw een his dual pursuits,w hich provide an important clue for the profound understanding of the complexity of his philosophy.
