The Structure Optimization And Performance Analysis Of Powder Injection Molding Turbine

Powder injection molding is the most potential method to manufacture complex and precision parts, which can hardly be produced by the traditional method. The turbine that manufactured by the PIM process have a very uniform microstructure, higher density. And the mechanical property is better than the turbine which is made by the precision casting process. Besides, the material utilization can reach more than 95%. So it has a great influence on saving strategic materials such as nickel-base super alloy. Furthermore, PIM has an advantage on minimum diameter, the minimum wall thickness, tolerance and surface roughness. Injection molding mould can be designed more flexible, which can broaden the design scope of turbine blade surface and turbine structure.In the view of the above, this paper takes JP60 C vehicle turbocharger turbine as the research object, making structure optimization to it, which coupling with characteristics of PIM process. Then make performance analysis on the optimized turbine. This thesis analyzes these areas and includes the following contents.(1) Based on the principle of optimal design, select the appropriate design variables. Make structural strength as the constraint condition, turbine weight as the optimization objective. Do structure optimization on the turbine using the software ANSYS. The optimization result shows that turbine has a weight loss from 124.776 g to 105.032 g, reduced by 15.82%. The weight loss effect is obvious.(2) Finite element model of the turbine impeller was established by using ANSYS, and do the strength and natural frequency research on the optimized turbine. Results show that: maximum equivalent stress of optimized turbine has increased, but it still in the range of material property. Besides, the position of the maximum equivalent stress and the maximum deformation has changed from the upper of turbine blade to the lower of turbine blade. And the low-order natural frequency of optimized turbine has decreased. But, the change of inherent vibration characteristics is not very obvious.(3)Make an analysis about how surface state, size effect and operation environment influence the turbine anti-fatigue life. Base on the results of the optimized turbine strength analysis, the stress concentration factor was calculated. Results show that: optimized turbine impeller is satisfied with the demands for life.(4) Calculate the critical speed of rotor-bearing system which assembles with the optimized turbine, using the software SAMCEF. Results show that: The second order critical speed has reduced from 90586r/min to 83726r/min, which reduced by 7.5%. Compared with original rotor system, first order critical speed and second order critical speed have a smaller gap. As the result, it can widen the rotor safe working speed range and improve the rotor dynamic performance.