| Journal bearing is an important part of rotating machine of gas turbine,steam turbine and gear box and so on.It has some outstanding advantages as stable work,high bearing capacity,low friction coefficient,good vibration absorbing,reliable operation and others.The development trend of modern engineering technology is to increase the bearing capacity and improve the bearing speed.But it will cause a dramatic increase of the temperature in the lube oil of journal bearings,reducing oil viscosity lubricating ability even lost.Many application and research cases on the rolling bearing,open gear,the train wheel rim and chain transmission have been proved that oil air lubrication(OAL)has good cooling performance,it is especially suitable for high temperature,polluted environment and extreme working conditions.But on the traditional journal bearing,the application of OAL face some difficult problems as bearing high temperature and low thermal efficiency that has not overcome.Theory and application are seldom reported,research is also in the lack of state that could not reflected the advantage of application of OAL in other areas has gained.This dissertation study OAL in the application of journal bearing as the research object,in view of the existing not ideal OAL cooling affection problem has carried on the detailed theoretical analysis and experimental research to OAL transport properties and structure.The main content of the dissertation are flowed:(1)The cause of the disorder on the application of OAL technology in the journal bearing is analyzed,the OAL technology in the technical approach of journal bearing on application is determined,and the mathematical model of describe the OAL journal bearing flow field and air-liquid two phase flow is established.(2)The flow characteristics of two phases in the horizontal OAL pipe is investigated by observational experiment,oil and air volume flow rate effect on flow pattern of two-phases and pressure drop in oil-air lubrication pipe are analyzed,pressure drop in oil-air lubrication pipe and its association formula are studied according to experimental data.The detailed oil and air two-phase flow transport properties in horizontal oil and air transportation pipe is obtained by numerical simulation and the calculated results are in good agreement with the experimental value.(3)The two-phase flow jet cooling hot rotating cylinder calculation model is set up and the numerical simulation is studied.The rule of two phase flow of oil and gas jet distance,jet Reynolds number and the cylinder speed change the cylinder in different regions and the overall average Nusselt number is obtained.The regulation of the influence of gas supply pressure and the axial distance from the nozzle to the fluid jet velocity is studied.(4)The influence of load,speed and other factors on the bearing to bush temperature,pressure and temperature distribution is studied by numerical simulation.Contrast analysis the relationship of no tank bush between OAL and oil lubrication the average convection heat transfer coefficient along with the change of the friction power is conducted.The different air flow rate on the influence law of OAL average convection heat transfer coefficient is obtained.(5)The shaft and bush friction in oil lubrication and OAL are comparative studied,and based on the temperature and friction factor of OAL bush the performance parameters of oil and air and the location and types of structure parameters are experimented,gives the main influencing factor of the temperature rise.(6)The contrast experiment of static characteristic parameters of new journal bearing lubrication and oil lubrication temperature rise,friction torque,friction factor and so on are carried on,and take temperature rise,friction torque and friction factor as the index to conduct orthogonal experiment of the load,oil,air and bearing structure factors,the main influencing factors of OAL journal bearing properties are obtained. |
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