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Analysis of two phase flow in liquid oxygen hybrid journal bearings for rocket engine turbopumps

Zhang Guoyuan (School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an, China)
Yan Xiu-Tian (Department of Design, Manufacture and Engineering Management, The University of Strathclyde, Glasgow, UK)

Industrial Lubrication and Tribology

ISSN: 0036-8792

Article publication date: 4 February 2014

272

Abstract

Purpose

A hybrid bearing of advanced cryogenic rocket engine turbopump is designed. For cryogenic fluid propellants (such as liquid oxygen) as the lubrication of bearing, bearings operating close to liquid-vapor region (near the critical point or slightly sub-cooled) are likely to develop a two phase flow region. The paper aims to discuss these issues.

Design/methodology/approach

In this paper, an all liquid, liquid-vapor mixture, and all vapor, i.e. a continuous vaporization bulk flow model of density and viscosity for mixture fluid, is presented, and the general Reynolds equation and energy equation with two phase flow as lubricants is solved. The static and dynamic performance of a 50-mm-radius hybrid bearing are obtained under 20,000 rpm speed and 10 MPa supply pressure.

Findings

The results show that the variations of performance of bearing operating under cryogenic liquid oxygen are not bounded by the all liquid and all vapor cases in the liquid-vapor mixture range. There behaviours are attributed to the large change in the compressibility character of the flow.

Research limitations/implications

For validating the correctness of analytical model, an experimental study on the liquid-vapor nitrogen mixture lubricated hybrid journal bearings is being carried out where low-viscosity nitrogen was selected as the lubricant for the sake of safety. Soon after, the authors will discuss the results and publish them in the new papers.

Originality/value

An all liquid, liquid-vapor mixture, and all vapor, i.e. a continuous vaporization bulk flow model of density and viscosity for mixture fluid, is presented. The static and dynamic performance of hybrid bearings with two phase flow as lubricants are obtained.

Keywords

Acknowledgements

The authors would like to thank the National Natural Science Foundation of China with No. 51205314 and the Fundamental Research Funds for the Central Universities with No. K5051304036 for their financial support.

Citation

Guoyuan, Z. and Xiu-Tian, Y. (2014), "Analysis of two phase flow in liquid oxygen hybrid journal bearings for rocket engine turbopumps", Industrial Lubrication and Tribology, Vol. 66 No. 1, pp. 31-37. https://doi.org/10.1108/ILT-09-2011-0072

Publisher

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Emerald Group Publishing Limited

Copyright © 2014, Emerald Group Publishing Limited

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