Numerical Investigation on the Flow-Induced Vibration Characteristics of Fire Turbopump with the Turbine-Pump Structure

Abstract

The vibration characteristics induced by radial hydraulic force on the fire turbopump have been investigated by numerical simulations in this paper. The numerical model was validated with corresponding experimental measurements. The turbopump has the special structure with two hydraulic machineries of a turbine and a pump. The hydraulic force characteristics on the separate turbine and the separate pump were first studied. There is one period in the force variation for one cycle of impeller rotation, and pressure fluctuations are observed in 15 times and 30 times the shaft rotating frequency of the turbine. Meanwhile, there are five periods in the force fluctuation in one full working cycle, and obvious fluctuation amplitudes on 5 times, 10 times and 15 times the shaft rotating frequency of the pump are found. Then, the coupled effect of force fluctuations on the turbine and pump was explored. For the turbopump, the periodicity of force fluctuation in the time domain and force characteristics in the frequency domain are dominated by pump structure. The hydraulic force fluctuation on the impeller is enhanced, while that on the housing is damped by counteracting the forces between turbine suction and pump volute.