Analysis of flow response to intake pressure pulse in a radial impeller

By discretizing the convective terms with AUSM+-up scheme in the rotating coordinate system, a finite-volume analysis code based on multi-block structured grids was developed independently, which aimed at realizing the numerical solving of internal flow fields of turbomachineries. Taking an unshrouded radial impeller as the research object, the flow response to intake pressure pulse was calculated. By comparing the response curves of inlet and outlet mass flow rates and aerodynamic torque calculated by the code and commercial software respectively, the accuracy of the unsteady flow solver was verified. The analysis of flow response data indicates that, the larger the mass flow of original working condition is, the smaller the disturbance ranges of aerodynamic force and torque will be, and also the damping of flow disturbance will be faster. The pressure spectrums of monitor points reflect that, and the peak frequency decreases slightly with the increasement of original mass flow. The varying degree of gas density is obviously smaller than mass flow, which means that the variation of mass flow is mainly contributed by the variation of flow speed, while the influence from density is relatively small.