Characteristic Analysis of Flow-Induced Vibrations on Inducer of Oxygen Pump

Abstract

Characteristics of e ow-induced vibrations in liquid-rocket-engine oxygen turbopump inducers are analyzed because the inducers were damaged in a test. Oscillating e uid mechanics theory and parametric polynomial method are used to solve the three-dimensional, steady and unsteady basic equations. It is found that the damage was caused by the oscillating pressure propagation, where a small external perturbation from the outlet of the inducer can be transformed to a very large oscillating pressure at some low frequencies. Some characteristics of inducers are analyzed to improve the severe e ow-induced vibration, such as increasing the inlet section length or the pitch, which can all decrease the pressure amplitudes effectively. Nomenclature a = coefe cient of parametric polynomial method for Wr b = coefe cient of parametric polynomial method for Wµ c = coefe cient of parametric polynomial method for Wz d = coefe cient of parametric polynomial method for P e = coefe cient of parametric polynomial method for N Wr f = coefe cient of parametric polynomial method for N Wµ fr = frequency of perturbation g = coefe cient of parametric polynomial method for N Wz h = coefe cient of parametric polynomial method for N P i = imaginary unit P = pressure q = any parameter of e owe eld Wr = velocity component in the r direction Wz = velocity component in the z direction Wµ = velocity component in the µ direction π = coefe cient of turbulent viscosity Ω = density A = angular velocity of the inducer ! = angular velocity of the perturbation Subscript