The Optimization Research Of Low Speed Ratio Adjustable Hydraulic Torque Converter

Hydro-mechanical speed control system has the advantages of low cost andlong life, it can also work in the harsh environment, wind power transmission devicewhich use it can ensure automatic control and the output speed constant, thus canconnect the synchronous motors. The torque converter in the wind powertransmission needs large high efficiency area and low ratio of transmission of thedesign conditions. Domestic low speed ratio adjustable torque converter still has noforming products. We only have one kind of low speed ratio centrifugal turbinehydraulic torque converter, that is NY5type starting torque converter, its secondguide wheel can be changed to the adjustable guide wheel. But the efficiency of thetorque converter is low, high efficiency area is also not small, so it can’t be appliedin the wind power hydro-mechanical transmission. This article would optimize thetorque converter, increase its effiency, enlarge its high efficiency field and change itto be adjustable torque converter.This article used the numerical simulation method to optimize the NY5typestarting torque converter. First the3D modeling of NY5type starting torqueconverter was presented. The grid was made and physical condition was defined.The article got the result after flow field calculation and compared it to theexperimental results, verified the accuracy of the numerical simulation’ results.Then optimization would be made in two steps: first, the cylindrical leaves of guidewheel would be changed to the space-warped leaves, and analyze the flow structureof the changed torque converter, analysis the reasons of some poor flow field suchas the return of flow and separation; second, aim at the results of first step, thearticle changed the turbine blade angle of the two turbines and redesign of the twoguide wheel blade to and optimized the converter is calculated, compared the flowfield before and after optimizing,analysis the effect of optimization.In this paper, the adjustable torque converter was needed to determine axis ofrotation of the adjustable guide wheel and the position of maximum opening ofguide vane. After determining the parameters of the adjustable guide wheel, thetorque converter which guide wheel was100%open,84%open60%open issimulated in full working condition, and analysis of flow characteristics. Finally, thearticle used the stream calculation methods and numerical simulation to get the axialforce of the adjustable torque converter, the results were contrasted between the twoto provided a reference for bearing selection, explored the method of calculation ofthe axial forceand gave a method to reduce the axial force.In this paper, the efficiency of the adjustable torque converter which was designed had achieved82.2%, the high efficient area had became2.26, couldcompletely be used in wind power transmission. The reason why the efficiency ofthe base type torque converter is low was found in the optimization process, that isthe deviation of the inlet flow of first turbine and the impact of loss at the entranceof the second guide wheel.