Performance Analysis And Experimental Research Of High Speed Heavy Duty Radial Sliding Bearing In Gas Turbine

As the gas turbine spindle as the support of some models with distributed tilting pad bearings,bearing working condition is usually a high speed and heavy load.But the conditions and limitation of the structure,the sliding bearing in starting and stopping stage is not using hydrostatic pressure auxiliary support system,and the solid lubrication film depends directly on the bearing surface directly by the gradual formation of boundary lubrication fluid lubrication,it will cause serious wear of bearings,bearing life influence.Therefore,the reliability analysis of tilting pad bearings in high speed and heavy load conditions is of great significance to the system.Aiming at the high speed and heavy load conditions inside the bearing temperature rise too quickly,based on the distributed six tilting pad journal bearing as the research object,established the pressure distribution of each pad under constant load and temperature distribution theory analysis model.This paper uses the finite difference method and over relaxation iteration for simultaneous solutions of two-dimensional Reynolds equation,energy equation,force and moment equilibrium equations,and considering the effect of viscosity temperature of lubricating oil,the oil film pressure distribution and temperature distribution in high speed and heavy load conditions distributed six tilting pad diameter of each pad in different loads,speed and different radial clearance under the action of.The theoretical results show that the high temperature rise larger loads,under heavy load temperature rise slow speed;the higher the temperature rise high,rising faster under high temperature;the relative gap of the hour temperature rise high,and the stability is not easy.Based on the theoretical analysis,according to the actual bearing structure size is developed for distributed six tilting pad journal bearing performance and test system.A mechanical system that meets the requirements of high precision rotating,high speed and heavy load conditions is designed.The lubrication system and data timing acquisition system that meet the requirements of large flow fuel supply are designed.The mechanical structural part puts the tested bearing on the cantilever end,and the two supports are on the same side.The power is provided by the electric spindle and the transducer debugging system.For the large temperature rise of the tested bearings,a special cooling circuit is designed in order to ensure the temperature stability.Aiming at the special structure of Bush,the installation structure of pressure and temperature sensor is designed.Data acquisition and processing program is compiled.Preliminary tests show that the test rig is full of practical requirements.Bearing tests were carried out on the PTFE coated shells.For each tile actual surface temperature and pressure distribution of sliding bearings of different speed and different loads.The results show that the bearing oil film pressure pad formation increased with increasing speed and load,and finally tends to be stable,while the non bearing area of tile formation of oil film pressure and the load and speed of the relationship is not great.Although with the pad temperature increase with the increase of load and speed,but the influence effect of load on the temperature was higher than the speed,the theoretical value is consistent with the experimental results.Finally,the failure of the surface PTFE film is analyzed and the improvement direction is proposed.