Design And Analysis Of Centrifugal Hydraulic Suspension Bearings For Swash Plate Engines

In recent years,the rapid development of the aviation industry has made outstanding achievements in innovation,development,key component manufacturing and maintenance,training,and other aspects.Different from general piston engines,piston engines in the field of general aviation have more stringent volume and mass restrictions.The use object of centrifugal hydraulic suspension bearings discussed in this article is the swashplate piston engine,which has the advantages of compact structure,high power to mass ratio,and high power density.This is precisely the core indicator for measuring aviation engines.At the same time,swashplate power machinery can operate in various complex and harsh working conditions,making it have great development prospects for improving the compactness and power to weight ratio of aviation piston engines.As the core component of rotating machinery,bearings play an important role in the normal operation of the spindle.For a compact swashplate engine,if magnetic bearing is used instead of the traditional contact bearing,although the friction coefficient can be reduced,it will also increase the complexity of the structure and increase the cost of processing,manufacturing and installation.Therefore,in order to avoid the problems faced by magnetic bearing and achieve the purpose of simplifying the engine structure and improving the power weight ratio of the engine,this paper aims to design a new centrifugal hydraulic suspension bearing to replace the traditional mechanical contact bearing and magnetic bearing.This hydraulic suspension bearing not only has the advantages of magnetic bearing,such as high speed,low wear,and outstanding dynamic characteristics,but also has a simpler structure and better stability,It can effectively avoid the problems faced by magnetic bearing.This thesis first took several common lubrication systems as the starting point,and combined the structure of the swashplate engine developed by the research group to determine the overall design scheme,main design parameters,design basis,and design process of the centrifugal hydraulic suspension bearing proposed in this article.Then,referring to the design method of the centrifugal hydraulic suspension blood pump,the structural parameters of the centrifugal hydraulic suspension bearing were designed,and its three-dimensional model was established in Solid Works.The structural analysis of each component and the entire bearing was carried out using Ansys Static Structure finite element software,and the results showed that its strain and stress met the strength requirements.Subsequently,theoretical calculations were conducted to verify that the number of radial flow channels in the model met the suspension conditions,and the model was simplified based on the calculation results.Fluid simulations were conducted on the radial flow channels of centrifugal hydraulic suspension bearings in Fluent,and a second structural scheme was proposed.By comparing and analyzing the simulation results of the two flow channel structures,it was proven that the original design scheme was reasonable.Finally,the flow field of the centrifugal hydraulic suspension shaft was simulated in Ansys Fluent.By applying three speed modulation waveforms of sine wave,triangle wave and square wave to the bearing inlet,the velocity distribution and pressure distribution of the flow field in the bearing were analyzed,and the average speed and average pressure curve of the bearing outlet plane were detected.The results showed that the average outlet pressure and average outlet speed of the three waveforms when rotating at an average speed of 3000 r/min were basically the same,The average pressure at the outlet is approximately 19000 Pa,with an average velocity of approximately 10.5 m/s.The average pressure is much higher than the reference value of 3-10 Pa,and the maximum velocity is within the range of 8-13 m/s.The average velocity curve and average pressure curve on the outlet plane are basically consistent with the modulation waveform,proving that the design of the centrifugal hydraulic suspension bearing designed in this paper is reasonable.