Study On Influence Of Blade Number To Performances Of Hydrodynamic Torque Converter

Hydrodynamic Torque Convert (HTC) is one of important elements for hydrodynamic transmission. It can change the speed and the torque steplessly and continuously. It has excellent self-regulation and adaptability, so it simplifies the operation radically. It can make the vehicles start calmly, speedup quickly, uniformly and gentleness. It can reduce the pinnacle-load and the torsion-shake, so it can prolong the life of the power transmission system. Due to above many strong points, the HTC is popularly used in the automatic transmission..The blade number is one of the key factors which affect the performances of HTC, and it wasn't comprehensively studied when people studied on how to improve the performances of HTC in the past, and the number of blade were designed based on 1-D flow theory and the experiences. If the experimental results meet the designed requirement, the number of blade will be determined as the blade number of HTC. From the above design method of HTC, we can see that the choice of the blade number is not only time-consuming, but also cost is high. With the development of science and technology, CFD technology had a significant impact on the design of HTC. Using CFD technology, the 3-D flow of HTC can be well understood, and the performances of HTC can be improved by changing the factors that effect HTC performances. Therefore, in order to design the blade number of HTC, provide valuable numerical theoretical basis, reduce the design cycle of HTC and improve the performances of HTC, the effects of the blade number on the performances of HTC can be studied using 3-D flow theory in this paper. There are six chapters in this paper.The background, purpose and significance are elaborated in the first chapter. The numerical simulation method that is pointed out is used to research the interior flow field; this method is an effective way to improve the performances of HTC. The developing situation of HTC in home and abroad, the application and developments of CFD in the studying of HTC are introduced. Scientific and feasibility of HTC design method based on CFD is expounded, and the contents that studied in this thesis are pointed out.The second, third, fourth chapter is closed in the field of research method, analysis process and experiment analysis to the internal flow of HTC etc. Taking the W305 as the prototype, the interior flow field numerical calculation of different impellers (pump, turbine and stator) blade number are carried out. The changes in the inlet and outlet of various impellers, and the pressure distributions in the pressure side and suction side of blades are analyzed. Based on the results of numerical calculation, the effects of different impellers blade number on the HTC performances are analyzed. In addition, the description of HTC to flow field analysis of the pre-treatment process is simplified appropriately. The result of the pre-treatment process which is a complicated and important process is directly used. The specific pre-treatment process include that the models of different HTC are built in UG, then the models are imported into ANSYS-ICEM and is carved up into grids by the multi-block method, the flow field is calculated by STAR-CD. In CFD software,the setup of calculation in detail is following : The control equation is time averaging N-S equations; the turbulence model is the k ?εstandard model, velocity-pressure couple method is SIMPLE method, and Upwind Differencing (UD) scheme is chosen for the discretion scheme.In the fifth chapter the principle of HTC impeller blade number combination is analyzed, and then it will be analyzed that the four typical combinations chosen from the entire impeller blade number combinations. The flow fields of different combinations of HTC are calculated by STAR-CD. Because of the limitation of prototype only a combination of HTC is experimental researched, experimental and calculated results are compared and the accuracy of 3-D flow field result is verified. The HTC performances of the different blade combinations of are forecasted and the effects of different forecasting on the HTC performances are compared.The sixth chapter is summary and outlook, the main contents that the thesis studies are expounded, and taking the main contents into account under the conditions of development and progress of the new technology and new means of continuous scientific experiments, some prospects for HTC research in order to have a better understanding for the 3-D flow field of HTC and improve the performances of HTC are suggested.