Numerical Calculation Of Cavitation Instability And Flow-induced Vibration Of A Liquid Rocket Inducer

Flow-induced vibration problems have become one of the major issues in a wide range of major industrial fields,such as Aerospace engineering,Ship engineering and Energy.It is an important factor that affects the reliability,safety and stability of the mechanical structure.In the axial inducers used for liquid propellant rocket turbopumps,typically working under cavitating conditions,it is usual to observe the development of flow instabilities.The flow instabilities and flow induced vibration,which can seriously degrade the performance of the machine or even cause its rapid failure,is the decisive factor affecting the operation safety and stability of the liquid propellant rocket engine.Therefore,the flow induced vibration characteristics of inducers plays an important role in the design of rocket propellant engine feed tuobomachinery.In this paper a fluid-structure interaction(FSI)solving strategy is applied to investigate the cavitation-induced vibration of a four-blade turbopump inducer.The main research contents and conclusions are as follow:A numerical method for calculating the cavitation flow of the inducer has been established.In the numerical simulation,a rotation-curvature correction was adapted to the k-ε turbulence model,and the Zwart cavitation model is used.The cavitation characteristics of the inducer are predicted and compared with the experimental data.The numerical results are in good agreement with the experiment data.The head coefficient error between the numerical results and the experimental results is less than 3.6%.It is proved that the numerical calculation method established in this paper can accurately predict the cavitating flow of the inducer.The numerical calculation and prediction of the performance and cavitation characteristics of the inducer have been carried out.The performance prediction of the inducer has been studied.The results of numerical calculation are in good agreement with the experimental results,and the maximum error of the head and efficiency is 7.6% and 15.2%,respectively.The cavitation characteristics of the inducer under different flow coefficients at a rotational speed of have been studied.With the increase of flow coefficient,the critical cavitation number of the head-break point of the inducer decreases.The instability of the cavitation flow in the inducer has been carried out.The numerical calculation of the unsteady cavitation flow of the inducer have been carried out.It is found that pressure distribution,vorticity distribution and the volume of channel cavitation show obvious pulsation characteristics.The pressure pulsation and the bubble volume pulsation of the inducer have the main frequency of the blade passing frequency.There are pulsating peaks of the pressure pulsation at integer multiple of rotation frequency.A numerical calculation method of fluid solid coupling for cavitation flow of the inducer has been established.The numerical calculation of cavitation-induced vibration of the inducer have been carried out.The rotation frequency of backflow oscillation is 12.45 Hz.The pressure pulsation of the monitoring points have a pulsating peaks at 12.45 Hz.The vibration of water guide cone has the main frequency of the blade passing frequency,and the main frequency of the vibration of the inducer blade is 12.45 Hz.