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Mathematical Problems in Engineering
Volume 2013 (2013), Article ID 651483, 9 pages
http://dx.doi.org/10.1155/2013/651483
Research Article

A Numerical Study on the Supersonic Steam Ejector Use in Steam Turbine System

China Ship Development and Design Center, Wuhan, Hubei 433064, China

Received 11 October 2012; Revised 22 November 2012; Accepted 6 December 2012

Academic Editor: Zhijun Zhang

Copyright © 2013 Lin Cai and Miao He. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Supersonic steam ejector is widely used in steam energy systems such as refrigeration, wood drying equipment, papermaking machine, and steam turbine. In this paper the Computational Fluids Dynamics (CFD) method was employed to simulate a supersonic steam ejector, SST k-w turbulence model was adopted, and both real gas model and ideal gas model for fluid property were considered and compared. The mixing chamber angle, throat length, and nozzle exit position (NXP) primary pressure and temperature effects on entrainment ratio were investigated. The results show that performance of the ejector is underestimated using ideal gas model, and the entrainment ratio is 20%–40% lower than that when using real gas model. There is an optimum mixing chamber angel and NXP makes the entrainment ratio achieve its maximum; as throat length is decreased within a range, the entrainment ratio remains unchanged. Primary fluid pressure has a critical value, and the entrainment ratio reaches its peak at working critical pressure; when working steam superheat degree increases, the entrainment ratio is increased.