涡轮增压器叶轮参数设计

Design of Parameter of Turbocharger Impeller

以叶片厚度、叶片数量、叶片冲角、出口后角为设计变量,以等熵效率和压力比为评价指标,通过四因素三水平正交试验,对柴油机涡轮增压器叶轮参数进行设计。借助流固耦合仿真分析,建立不同因素水平下叶轮的有限元模型,获得等熵效率和压力比,验证设计变量。分析结果表明,质量流量为2 kg/s时,叶轮等熵效率和压力比的仿真预测结果分别为84.4%和1.73,仿真预测误差满足工程应用要求,由此证明模拟的准确性。叶片厚度为2.5 mm,叶片数量为23,叶片冲角为14°,出口后角为64°时,涡轮增压器的性能最佳。影响叶轮等熵效率的设计变量从大到小依次为叶片厚度、叶片数量、叶片冲角、出口后角。在质量流量1.5~3.5 kg/s范围内,设计变量优化后等熵效率和压力比均提高。通过实践确认,正交试验设计方法可以用于叶轮参数的设计与改进。

By employing the blade thickness,blade number,blade impulse angle,and outlet back angle as design variables,as well as the isentropic efficiency and pressure ratio as evaluation indicators,a four factor and three level orthogonal experiment was performed to design the parameter of the turbocharger impeller of a diesel engine.With the aid of fluid-solid coupling simulation analysis,the finite element model of the impeller under different factors and different levels was established to obtain the isotropic efficiency and pressure ratio,and verify the design variable.The analysis results show that when the mass flow rate is 2 kg/s,the simulation prediction results of the isentropic efficiency and pressure ratio of the impeller are 84.4%and 1.73,respectively.The simulation prediction error meets the requirement of engineering application,which proves the accuracy of the simulation.The best performance of the turbocharger is achieved when the blade thickness is 2.5 mm,the number of blades is 23,the blade impulse angle is 14°,and the outlet back angle is 64°.The design variables affecting the isotropic efficiency of the impeller are blade thickness,blade number,blade impulse angle,and outlet back angle in descending order.In the range of mass flow rate 1.5~3.5 kg/s,the isotropic efficiency and pressure ratio are increased after optimization of the design variable.It is confirmed through practice that the orthogonal test design method can be used for the design and improvement of the parameter of the impeller.