车用余热回收系统涡旋膨胀机涡旋盘应力变形分析

Stress and deformation analysis of scroll disk of a scroll expander for waste heat recovery of vehicle

以车用发动机有机朗肯余热回收系统中的某型涡旋膨胀机为研究对象,通过对比分析施加基于线性分布的温度载荷和基于流场的热边界载荷下涡旋盘的热应力和热变形的分布差异,以及对比分析热力学模型下和基于流场结果下涡旋盘所受气体力作用造成的变形情况及应力分布,研究涡旋膨胀机涡旋盘应力变形情况及分布规律,并探究了载荷耦合作用下和载荷单独施加下涡旋盘形变的不同和变化规律。结果显示:温度载荷是影响涡旋盘变形的主要因素;基于流场下的涡旋膨胀机运行参数更符合其实际工况,温度分布更合理;膨胀腔压差越大,波动越大,形变量越大,且与吸气腔相连的第一膨胀腔形变最明显。载荷单独施加和载荷耦合下的形变规律相似,最大应力和变形均出现在涡旋齿始端且随展开角的增加应力与变形量逐渐减小,耦合作用下的应力变形大于单独施加下的应力变形且不是简单的线性叠加。

A model of a scroll expander in the organic Rankine waste heat recovery system is developed and used to investigate the distribution law of stress and deformation.Firstly,a comparative study of the stress and strain of the scroll under two thermal boundary conditions is made,and then the deformation law of the scroll under the action of two gas forces is observed in ANSYS.Finally,the deformation distribution of the scroll is simulated and analyzed by the coupling action.The results show that the temperature load is the main factor affecting the deformation of the scroll.The operating parameters of the scroll expander based on the flow field are more suitable for its actual working conditions,and the temperature distribution is more reasonable.The greater the pressure difference in the scroll expansion chamber,the greater the deformation.And it is the most obvious where the first expansion chamber connected with the suction chamber.In addition,the law of deformation under load alone is similar to that of the coupling action.The maximum stress and strain appear at the beginning of the scroll tooth.The results also confirm that the stress deformation under the coupling action is greater than the stress deformation by individual effect,and it is not a simple linear superposition.