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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2016, Vol. 37 ›› Issue (3): 1060-1073.doi: 10.7527/S1000-6893.2015.0086

• Material Engineering and Mechanical Manufacturing • Previous Articles     Next Articles

Oil droplets fractions and oil droplets/air energy transfer analysis in bearing chamber

SUN Hengchao, CHEN Guoding, WANG Li'na, WANG Fei   

  1. School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an 710072, China
  • Received:2015-02-10 Revised:2015-03-13 Online:2016-03-15 Published:2015-03-27
  • Supported by:

    National Natural Science Foundation of China(51275411)

Abstract:

Previous investigation of oil motion in bearing chamber has not considered the heat transfer between oil droplet and air, moreover, the determination of oil droplet fraction is lack of accurity when treated the oil droplets and air as homogeneous phase. To overcome the above limitations, this paper proposes the analytical method of oil droplets fractions and oil droplets/air energy transfer in bearing chamber by virtual of calculating both oil droplet motion and droplet size distribution. Firstly, considering the heat convection between oil droplet and air, the oil droplet thermal equation is embedded into its motion equation. The associated equations are solved simultaneously by an instantaneous step method to obtain the velocity and temperature of oil droplet. This treatment of considering oil droplet/air heat transfer can enhance the accuracy of droplet velocity by comparison of theoretical and experiment results. Secondly, the oil droplet diameter probability density function and the frequency of droplets generation in bearing chamber are obtained; by dispersing droplet diameter range and oil droplets/air mixture flow field, the oil droplets fractions and energy transfer with air at different radial positions are calculated by oil droplet motion analysis. Lastly, a rotating disk chamber test rig is established to investigate oil droplets' volume fraction. The measurement of oil droplets volume fraction is carried out. The proposed theoretical model is validated by experimental results. Such improved model overcomes the shortages of previous study, which failed to take account of the oil droplet/air heat transfer in oil droplet motion, as well as the oil droplets fraction has less accuracy among the oil droplets/air homogeneous flow simulation.

Key words: aeroengine, bearing chamber, droplets, droplet size distribution, heat transfer, fraction, thermal energy, kinetic energy

CLC Number: