【作者】 杨帆；

【导师】 张翼；

【作者基本信息】 中北大学 ， 动力机械及工程， 2012， 硕士

【摘要】 涡轮增压器能在不加大发动机排量的情况下较大幅度地提高发动机功率及扭力，减少汽车尾气中的有害气体量，已经成为汽油机、柴油机的高性能配套装置。车用涡轮增压器中的气体流动为脉动的非稳态流动，再加上排放的气体温度很高，所以大幅度提高涡轮承载负荷能力成为当前先进涡轮发动机设计的重要技术追求。采用流固耦合方法在多场条件下对涡轮叶轮进行结构强度分析能够比较真实地模拟实际情况，使计算结果更加精确、可信。本文应用CFX-ANSYS软件对涡轮进行了耦合分析，认为由叶片变形和其他因素所引起的流场变化现象不予考虑。本文首先在CFX中对涡轮内部废气区域的流场进行了稳态计算，通过与试验结果对比得出该计算结果的准确性，在此基础上以稳态计算结果为初场对流场进行瞬态计算，得到流固交界面处流场的温度及压力。采用建立表面效应单元的方式将在不同排气压力情况下流场计算结果映射到涡轮叶片上作为载荷，对涡轮叶轮进行温度场的计算，得到固体的温度场分布。在综合考虑旋转离心力、热应力、叶片表面气流激振力这三种因素的情况下对涡轮叶轮进行结构强度计算，得到涡轮叶轮的应力及应变。在整个排气循环中，整体叶轮温度波动范围在770K-1072K，应力波动范围在131MPa-686MPa，应变波动范围在0.594mm-1.790mm，符合材料的许用应力，该叶轮结构是可靠的。本文的结论对该型号增压器涡轮的结构强度分析以及改进设计有一定的参考价值。更多还原

【Abstract】 Turbocharger can greatly improve the engine power and torque , reduce harmful gas intail gas without increasing the delivery capacity of engine. It has become the gasoline engine,diesel engine with high performance matching device.The gas flow in vehicle turbocharger ispulsation of unsteady flow ,at the same time the temperature of the gas is high, greatlyimprove the turbine load becomes the current advanced turbine engine design importanttechnical pursuit. Using the fluid-solid coupling method in field under the condition of theturbine impeller structure strength analysis can simulate the actual situation, the calculatedresults are more accurate, credible.This paper argues that the blade deformation and other factors caused by the change offlow field phenomenon will not be considered with studying of the fluid structure Interactiontheory.It analysis the weakly interaction with CFX-ANSYS software.At first ,the papercalculate the flow field of the exhaust gas region in steady, through the comparison withexperimental results shows that the calculation results of the stability,then do transientcalculation on the basis of the result.The computational result is mapped to the turbine bladesby using surface effect element on the calculation of the temperature field of turbine impeller.In considering the centrifugal force of the rotation, thermal stress, leaf surface airflowexciting-vibration force of these three factors in the case of the turbine impeller structurestrength analysis. In the whole cycle of integral impeller exhaust, temperature fluctuations inthe range of 770K-1072K, stress fluctuation range in 131MPa-686MPa, strain fluctuationrange in 0.594mm-1.790mm.The conclusion of this paper has some reference value in analysis of the structurestrength and improved design of this type turbocharger.更多还原