Design And Analysis On The Guide Vane Of A Mixed-flow Turbo

In recent years,the environment and energy problems have become more and more serious with the automobile industry developing rapidly.The turbocharger that equipped with adjustable guide vane turbine can achieve good matching with the engine at full operation conditions,which has become a main technology method in developing the performance and decreasing the emission of engine.By integrating the variable nozzle and mixed flow turbine technologies,researching and developing the variable nozzle can increase the turbine's efficiency significantly.At present,the research focus has been aimed at the turbine characteristic and internal flow of the radial turbine and axial-flow turbine.However,few studies are carried out on the adjustable mixed flow turbine,therefore,an adjustable guide vane mixed flow turbine that in application is chosen as the research object,and the guide vane clearance leakage flow characteristic was studied by the numerical simulation method.According the leakage flow characteristic,two partial rotation guide vanes,the forepart rotation vane and the rear rotation guide vane,were designed and analyzed by the methods of CFD and empirical formulas.The main research results as follows:After the turbine adopted the partial rotation guide vanes,the guide vane leakage flow was decreased significantly for the clearance length shortening.According the computational results of those three variable guide vanes at 20% and 40% opening conditions,it can be seen that the clearance leakage flow of the two partial rotation guide vanes is significantly decreased compared to the original guide vane,which also decreased the loss inside of the nozzle and the rotor.The leakage flow of two partial rotation guide vane exist obviously differences on the flow intensity and flow form.Compared to the original guide vane,the partial rotation guide vanes have large advantages in enhancing the rotor blades reliability.When the turbine works at the nozzle small opening and large expansion ratio conditions,there is a strong shock wavegenerates near the original guide vane trailing edge for the gas accelerates excessively.However,for the forepart rotation vane,there is no shock wave generates and there is a weakened shock wave insides of the rear rotation guide vane compared to the original vane.At 40% guide vane opening condition,the shape of the rear rotation guide vane is not smooth,which causes a strong back flow near the rotation clearance and lead to large losses.The contrast of the two partial rotation guide vanes computational results shows that the adjustment ability of the forepart rotation guide vane is higher than that of rear rotation guide vane for it has a large setting location radius.The partial rotation guide vanes can improve the performance of the turbine significantly,and the forepart rotation guide vane have a better performance compared to the rear rotation guide vane.