| Journal bearing is an important part of rotating machine of gas turbine,steam turbine and so on.It presents outstanding advantages such as stable work,high bearing capacity,low friction coefficient,anti-shaking,reliable operation and others.As demand of higher power,higher speed and lower temperature rise of journal bearing,high performance lubrication technology is required.The traditional lubrication method is currently threatened with a high temperature rise of bush and the lower the viscosity of oil.Oil air lubrication(OAL)is one of the most effective lubrication method,practice has proved that it is an advanced form for rolling bearing,but not journal bearing.In order to fill the void on using OAL in journal bearing,this dissertation tries to form an airflow path by the improving the structure of bearing,and conducts theoretical and experimental research in details within aspects including practicability of OAL using in the journal bearing,lubrication and cooling performance of OAL,characteristics of jet impingement,and OAL effects on journal bearing performance.Firstly,both the trend and obstacles of the lubrication theory,journal bearing structural style,oil air lubrication technology and jet impingement cooling have been reviewed.The fundamental equations of gas-liqued two-phase flow are given based on the flow behavior of OAL.The DPM model is applied in accordance with the flow behavior of OAL.Secondly,with the Sliding friction pairs and journal bearing being the research object,the OAL effects on Sliding friction pairs and theirs influencing factors have been analyzed.Four flow channel of journal bearing for air movement have been analyzed designed by the improving of the oil groove of bush,and jet impingement cooling effects of four flow channel have been comparative analyzed.The jet Reynolds number,impact of distance and rotation of axes’ effects on jet impingement cooling effects have been simulated.Thirdly,for solving the effects of aerated oil on lubricating properties,an analytical models are derived for the viscosity and the density of aerated oil in journal bearings.The effects of void fraction on lubricating properties in different eccentricity ratio and different speed have been analyzed.At last,the experimental between oil gas lubrication and submerged lubrication are done using friction-abrasion testing machine.By measuring temperature rise and the friction coefficient of two lubrication systems in the same conditions.The rationality and validity of OAL on journal bearing are verified by the experimental results. |
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