透平膨胀机转子系统在耦合应力下的强度分析

Strength Analysis Based on Coupling Stress of Turbo-Expander Rotor System

关于透平膨胀机转子系统优化设计问题,针对强度分析,了解应力的分布状态,可以准确地处理膨胀机中高速气流和极大温差下的多场耦合环境,为强度设计和优化提供条件。为此提出采用流体-温度-结构三场顺序耦合原理,在ANSYS Workbench平台上,用N-S方程计算膨胀轮和增压轮在高速气流作用下的表面压强和表面温度分布,用导热微分方程得到转子系统的实体温度分布;最后,综合考虑作用在转子系统上的气动力、热应力和离心力,从结构强度理论角度分析并校核各个零部件的强度。分析中由于忽略了叶轮的轮盘和轮盖外表面气压,因此采用考虑和不考虑内表面气动力两种方案,对转子系统的应力分布进行了仿真,结果表明转子系统各个零部件的强度均满足工况设计要求。

With regard to the design optimization of turbo - expander＇s rotor system, the acquaintance of stress distribution aiming at that strength analysis will help to treat accurately the multi -fields coupling environment inclu- ding high - speed flow and thermal effect, which can contribute to the strength design and optimization. Therefore, this paper adopted the fluid - thermal - structure sequential coupling principle, applied N - S equation to calculate the surface pressure and temperature distribution of impeller by the action of high - speed flow Then it obtained the body temperature of rotor system with heat equation. Finally, taking aerodynamic force, thermal stress and centrifugal force into consideration, the paper checked the structure strength of every component in the rotor system from the viewpoint of strength theory. Due to the neglect of exterior pressure on the hub and shroud, the paper simulated the stress distribution from two schemes considering or not considering the interior pressure. The simulation results indi- cate that the strength of every component in the rotor system meets the design requirements, which can provide an ef- fective reference for the design of turbo - expander.