Dynamic Model Research Of Post Stall In Compression System

Based on the requirements of designing Anti-surge systems, this paper carried out the dynamic research of post stall on compression system. The study object consisted of three different types of compression system: compressor, a uniaxial turbojet engine, a small bypass ratio turbofan engine.By simplifying of internal flow field and the division of structural units, the physical model of compression system was established. Any element’s governing equation was two dimensional Euler equations with source term, given boundary and initial conditions, and solved by Runge-Kutta method.According to the theoretical model and based on VC ++ language platform, a user-friendly analysis system for dynamic characteristic of post stall in engine has been developed. Software has a convenient model editing capabilities, and the ability to display or output the results in an intuitive form of graph or table.By using the software, the dynamic processes of rotating stall and surge in three kinds of compression system has been simulated, the results can accurately reflect the rotating stall and surge’s basic features, verified the reliability of model and calculation method. The precision of surge frequency for turbofan engine has been verified by test experiment on a type of engine in our country,and meet the engineering accuracy requirement. By adjusting the opening of nozzles, succeed in simulating the recovering from stall in compression system. The results showed: there was no flow lag in process of recovering from surge, while the process of recovering from rotating stall has flow lag.The research of exhaust nozzle plenum’s effect on surge frequency has been carried out, found that:the larger exhaust nozzle plenum, the lower surge frequency, which is consistent with existing knowledge.