Research On Lubrication Characteristics Of Water Lubricated Bearing On The Condition Of Dry And Wet Rotor Water Film In High Pressure Pump

In the seawater desalination process, membrane module, pump and energy recovery unit are the three key components, and the high pressure pump usually operate as the most important power equipment. Development of high efficiency and reliability seawater desalination high-pressure pump with independent intellectual property rights of our country is particularly necessary and urgent, which is of great strategic significance to industrialization. As the supporting part of the high pressure pump, the water lubricated bearing plays a decisive role in improving the efficiency and simplifying the structure of the pump. In order to improve the operation stability of seawater desalination high pressure pump, it is very important to study the lubrication characteristics of water lubricated bearing.This paper supported by National Key Technology Support Program "Seawater desalination high pressure pump and the booster pump development" and Chinese National Natural Science Foundation Project "Seawater desalination high-pressure pump water lubricated bearing-rotor coupling system transient dynamic characteristics". According to the structural characteristics of the high pressure pump, a special water lubricated bearing test rig used as the research object was developed. The numerical simulation and experimental study on the axis orbit of water lubricated bearings under dry and wet conditions were carried out to obtain the axis orbit and the pressure distribution of bearing. Comparative tests on circumferential pressure distribution of water lubricated bearing under conditions of dry and wet rotor were also investigated. The main research contents are as follows:(1) Numerical calculation of FSI based on CFX can obtain the water lubricated bearing axis orbit transient characteristics under the different rotating speed, pressures, interval and L/D.(2) According to the main structure of the seawater desalination high pressure pump, water lubricated bearing test rig was designed according to the proportion of 1:2. Two vertical displacement sensors are arranged on the rotor to measure the axial trace of water lubricated bearings. According to the lubrication theory, six pressure sensors are arranged in a suitable position, and the dynamic pressure lubrication state of the liquid film is collected. Through the change of the inlet and outlet conditions, the water lubricated bearing of dry and wet rotor was realized. And 26 groups of test programs were designed to carry out the axis orbit and the bearing pressure distribution.(3) The influence of the different parameters of the water lubricated bearing is revealed by the test study of the influence of the axial orbit.(4) The pressure distribution of water lubricated bearing under dry and wet conditions is analyzed. The time domain diagram of bearing pressure distribution under different parameters is analyzed firstly, and then the pressures fluctuation frequency domain diagram is obtained by FFT transform. The influence of different parameters on the stability of water lubricated bearing system is revealed from the point of pressure fluctuation. And the result of pressure fluctuation test is basically consistent with the test result of axis orbit.