Drag Reduction and Performance Improvement of Hydraulic Torque Converters with Multiple Biological Characteristics.

Liu Chunbao,Liu Changsuo,Lei Yulong,Li Li,Zhang Yubo

doi:10.1155/2016/3641651

Abstract

Fish-like, dolphin-like, and bionic nonsmooth surfaces were employed in a hydraulic torque converter to achieve drag reduction and performance improvement, which were aimed at reducing profile loss, impacting loss and friction loss, respectively. YJSW335, a twin turbine torque converter, was bionically designed delicately. The biological characteristics consisted of fish-like blades in all four wheels, dolphin-like structure in the first turbine and the stator, and nonsmooth surfaces in the pump. The prediction performance of bionic YJSW335, obtained by computational fluid dynamics simulation, was improved compared with that of the original model, and then it could be proved that drag reduction had been achieved. The mechanism accounting for drag reduction of three factors was also investigated. After bionic design, the torque ratio and the highest efficiencies of YJSW335 were both advanced, which were very difficult to achieve through traditional design method. Moreover, the highest efficiency of the low speed area and high speed area is 85.65% and 86.32%, respectively. By economic matching analysis of the original and bionic powertrains, the latter can significantly reduce the fuel consumption and improve the operating economy of the loader.

Highlights

A hydraulic torque converter is a kind of turbomachine that is widely used in automatic transmissions for automobiles and engineering machinery
The results showed that, in the circumstances of the same concaves density, the rectangular array showed the best drag reduction effect
Inspired by head of dolphin, the first turbine and stator were designed as dolphin-like structure

Summary

Introduction

A hydraulic torque converter (torque converter or TC) is a kind of turbomachine that is widely used in automatic transmissions for automobiles and engineering machinery. Drag reduction especially in boundary layer flow is significant for torque converter. Inspired by the focal plane and thickness of fish, it will help to reduce the profile loss in torque converter. Many kinds of bionic nonsmooth surfaces, like riblets and others, are already used in industrial flows to obtain drag reduction successfully [14,15,16,17,18]. The nonsmooth surfaces mainly achieve the drag reduction by decreasing the friction loss in boundary layers, which have their potential drag reduction in torque converter. The focal plane and thickness of fish, the nonsmooth surfaces, and the structure of dolphin’s head are combined together attempting to achieve drag reduction and improve the performances of torque converter, especially efficiency. Considering published literatures, those factors or their combination is rarely applied in torque converter to obtain drag reduction

Coupling Bionic Design Based CFD Simulation

Performance Prediction for Three Coupling Bionic Factors

Conclusion