内燃机冷风扇设计的新方法-外文翻译.docxVIP

New Design Method For Engine Cooling FanHuang Hongbin zheng Shiqin Liu Shuyan Yan Weige(School of Vehicular Engineering, Beijing Institute if Technology, Beijing 100081)Abstract Aim To put forward a type of math model for optimizing fan’s twisting law.Methods This math model was based on turbo-machinery euler equations and calculus of variation, it was conducted for optimizing the aerodynamic parameters along the blade height of the fan and the math method was produced for the optimization of fan’s twisting law. Results the type 6102Q engine cooling fan was optimized by use of this model,and the calculation data were contrasted with those of iso-reaction coefficiency flow type and free vortex flow type. Some problems existing in long blade can be solved by use of above method.Conclusion The design paramters needn’t be determined artificially, so calculating results are more rational to a high degree than that from other methods.Key words: cooling fan, twisting law, optimum designThe design of fan has been a hard work on the orientation of aerodynamics because of the omplicated flow through the blades, so the fan had been designed by use of kaufman theory. This law believes that the flow through the fan blades is of one-dimension , the airflow parameters at the mean blade diameter are taken into account, but the flow through the root and tip is negative. After that, fan was projected according to the simply radial balance equation. Numerical precision was enhanced by use of completely radial equilibrium equation and iso-reaction factor of twisting law to determine the air-flow parameters along the blade radial direction, so the flow losses of tip and root are lessen to certain extent.In this paper ,the authors put forward a math model for optimizing airflow parameter along blade height by use of euler equations and calculus of variation.1．MATH MODELWhile the minute matter △G flows around the blade which is formed by two neighboring flow surfaces,according to E