Study On Dynamic Characteristics Of Fluid-Structure Interaction Of Impeller Front Shroud

Centrifugal impeller is the core component of centrifugal pump,which is used widely in power, energy, chemical and aerospace fields. The dynamic performance of the centrifugal pump rotor system is the fundamental factors to the stable and reliable operation.Fluid interactions between impeller and the fluid will have an important impact on the dynamics performance of pump rotor system,especially under high-speed,heavy load conditions.In this paper,by theoretical modeling and numerical analysis, the dynamic, of an impeller front shroud,under fluid-structure interaction between the fluid and the front cover of impeller is studied.Since the numerical integration of the complete Navier-Stokes equations is very time-consuming, Bulk-Flow model is used to derive the governing equations of control volume in the fluid of front shroud channel.The governing equations are composed of a set of partial differential equations under the impeller eccentric environment. The finite difference method is used to solve these non-linear equations, for its better quality of continuity. Perturbation analysis is conducted to produce a set of the zeroth-order equations and a set of the first-order equations. The Simple algorithm is used to integrate the zeroth-order equation. Variable separation method is used to solve the first-order perturbation equations.Pressure and velocity distributions in steady state are obtained from the zeroth-order equations, dynamic coefficients of the impeller are derived from the first-order equations.Based on the numerical results, the influences of some relevant parameters of the impeller, say, the gap between the front shroud and housing, the length of the front shroud,the inclination of front shroud, the eccentricity of the rotor, on the steady-state pressure and velocity distributions are analyzed. And also, their effects on the dynamic coefficients of the impeller are discussed. Conclusions are obtained as follows:(1)The axial length,inclination angle of the front shroud impeller speed only have impacts on the circumferential velocity distribution. The gap between front shroud and housing and rotor eccentricity have impacts on both the pressure and velocity distributions.(2) Rotor speed has more significant impacts on cross coefficients than direct coefficients.