Basic Research Of Hydrostatic/Hybrid Journal Floating Ring Bearing Turbulent Characters

As the development of modern industry, aerospace and various precision machine tools and other high-speed ultra high-speed rotating machinery on higher and higher demands to bearings. Using hydrostatic/hybrid journal floating ring bearings is an effective means to improve the speed of bearing-rotor system, many scholars take great attention to this. The current study for the majority of floating ring bearings is based on laminar flow assumption. Along with the improvement of bearing speed, Reynolds number increases, the flow of bearing oil film within has become turbulent from laminar, therefore, studying the characteristics of floating ring bearings in laminar flow is far from the actual working conditions of the high-speed film. We need to research the various characteristics of floating ring bearings in turbulent flow operating conditions.This dissertation takes the high-speed radial-thrust hydrostatic/hybrid journal floating bearing as a research object, founds the turbulent mathematic model of it, calculates inner and outer films'static and dynamic characters with the FEA method. Compares the data of bearing in turbulent flow condition with it of bearing in laminar flow condition. Analyses the reason of the differences between these two flow states, also the influence of the Reynolds number and eccentricity to the characters. Study mainly includes the following two aspects.1,On basis of law of wall, the dissertation gives the high-speed radial-thrust hydrostatic/hybrid journal floating bearing in turbulent flow state, the expressions of static and dynamic coefficients, bearing equivalent stiffness and damping coefficients. Apply the FEA algorithm to calculate the oil film'pressures, the static and dynamic characteristic coefficients of bearing system in equilibrium condition in different eccentricity.2,Analyze the differences between laminar flow data and turbulent flow data, and all the coefficients of bearing in turbulent flow state by changing rotating speed and eccentricity. Draw the characteristic curve in various working conditions. The analysis results shows:when the bearing runs at high speed, the lubricant film is in the turbulent state, laminar flow assumptions is no longer suitable for high speed bearings.