Research On Fault Mechanism And Diagnosis And Treatment Technology Of Turbo Pump In Liquid Rocket Engine

The high-thrust liquid rocket engine is a very important strategic equipment of China.Its component turbo pump is an important part of the engine,whose working environment is very harsh.The extreme working environment makes the turbo pump have a very high failure rate.In the development of rocket engines,the problem of rotor instability that has plagued turbo pumps in the past will be more prominent.Ultra-high speeds make rotor dynamic balancing become a new difficulty.This paper aims at the simulation analysis of the dynamic characteristics of a certain type of hydrogen turbo pump and the design of test bench and other related issues,whicn has done the following work:(1)According to the rotor structure of a certain type of hydrogen turbo pump,the rotor shaft system modeling method considering the interference assembly of the impeller and the thread preload and the additional rigidity of the rotor sleeve is studied.The method of using the impeller hub thickness unchanged and reducing the thickness of the remaining sleeves and bearing inner rings to simulate the weakening effect of the existence of the contact surface of the rotor sleeves and bearing inner rings on the overall rigidity of the rotor is adopted.The dynamic calculation model of the hydrogen turbo pump is established,and its dynamic characteristics are comprehensively calculated and analyzed,including critical speed and vibration mode,unbalanced response analysis and rotor stability analysis,etc.,which provides theoretical basis for the high-speed dynamic balancing of the hydrogen turbo pump rotor.(2)Based on the ANSYS workbench platform,the CFD method was used to analyze the dynamic characteristics of each seal gap(including air flow gaps and liquid flow gaps)of the hydrogen turbine pump rotor.The leakage characteristics and dynamic characteristic parameters of the seal are obtained,and the data are fitted to obtain the stiffness and damping coefficients of different seal positions.Based on the obtained seal stiffness and damping coefficient,the effect of the dynamic characteristics of the seal on the dynamic characteristics and high-speed dynamic balancing of the hydrogen turbo pump rotor was studied.(3)Designing a high-speed rotor dynamics test bench for hydrogen turbo pump rotor dynamics research and rotor high-speed dynamic balancing test requirements,which can realize the hydrogen turbo pump rotor dynamics research and rotor high-speed dynamic balancing at full operating speed.In order to conduct the high-speed dynamic balancing test of the hydrogen turbo pump rotor,a high-speed rotor balancing scheme was proposed.And the virtual balancing of the hydrogen turbo pump rotor model based on the influence coefficient combined with weighted least square method was carried out,which verified the feasibility of the scheme.At the same time,a dynamic balancing method without key-phase signal is proposed,which can be applied to the research of the hydrogen turbo pump rotor high-speed dynamic balancing method,providing a new direction for rotor dynamic balancing.