| Hydraulic torque converter(HTC)has the unique advantages of good working condition self adaptability and low-speed stability.It is widely used in vehicles and construction machinery.As a key transmission equipment,the improvement of its performance is of great significance to the dynamic performance and fuel economy of vehicles.Taking the hydraulic torque converter independently developed in China as the research object and CFD as the tool,this paper analyzes the influence of internal leakage in the hydraulic torque converter on its performance;A blade parametric modeling method based on Rukovsky theory is proposed,which widens the application scope of Rukovsky theory;The quadratic polynomial relationship between design parameters and performance parameters of hydraulic torque converter is established,which is of great significance to improve the performance of torque converter.Firstly,3D modeling of hydraulic torque converter is carried out through reverse3 D scanning.Using the unsteady three-dimensional flow field simulation analysis of the whole channel,it is found that there is circulating flow in the internal leakage area,which affects the performance of the hydraulic torque converter;There is a flow separation phenomenon on the suction surface of the guide wheel,which affects the performance and flow stability of the hydraulic torque converter;Due to the different number of blades of each impeller,there are confluence and diversion phenomena during the operation of the torque converter.Too few blades will weaken the ability to control the fluid,and too many blades will squeeze the fluid.Secondly,Aiming at the problem of internal leakage in the hydraulic torque converter,the leakage area in the torque converter is closed for simulation.By comparing the flow field and performance of leakage and no leakage in the torque converter,the impact of internal leakage on the torque converter is analyzed.It is found that no matter how the speed ratio changes,the flow in the internal leakage area always accounts for 12% of the main flow.When the 12% internal leakage flow acts on the blade,the working efficiency of the hydraulic torque converter can be improved by3.4%.Thirdly,aiming at the phenomenon of fluid flow separation in the guide wheel,the shape of the guide wheel blade is parameterized and optimized,and the optimization and improvement of the joukowsky airfoil theory is proposed,which widens the application scope of the theory,so that the method which is only suitable for airfoil design can be widely applied to the parametric design method of large angle turbomachinery blades.At the same time,the optimal parameters are determined through multi-objective optimization,which improves the working efficiency of the torque converter by 3.92%.Fourthly,in view of the confluence and diversion phenomenon caused by the different number of impeller blades of the torque converter,the single factor and multi factor analysis of the blades of the torque converter are carried out to obtain the influence law between the number of blades of each impeller and the performance of the torque converter and the influence effect between multiple factors of the torque converter,and the quadratic multinomial relationship between the number of impeller blades and the performance parameters of the torque converter is established,It is found that there are many groups of blade combinations with high performance within the scope of this study.Finally,through a series of optimization design,the prototype test is carried out on the guide wheel of the torque converter with 3D metal material printing and the blades of each impeller with manual spot welding.The results show that the maximum efficiency is increased from 0.810 to 0.841,working efficiency of the optimized hydraulic torque converter is improved by 5.8%,the torque coefficient of pump wheel is increased by 3.6%,the range of high efficiency has been widened by 6.0%,and the overall performance has been greatly improved,which verifies the effectiveness of this research. |
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