Computational fluid dynamics simulation of the supersonic steam ejector. Part 2. Optimal design of geometry and the effect of operating conditions on the ejector

Abstract

The aim of this study is to investigate the use of computational fluid dynamics in predicting the performance and optimal design of the geometry of a steam ejector used in a steam turbine. In the current part, the real gas model was considered using IAPWS IF97 model, and the influences of working fluid pressure and backpressure were investigated. The results illustrate that working critical pressure and backflow critical pressure exist in the flow. Moreover, the entrainment ratio reaches its peak at the working critical pressure. The performance of the ejector was nearly the same when the outlet pressure was lower than the critical backpressure. Effects of ejector geometries were also investigated. The distance between the primary nozzle and the mixing chamber was at optimum, the length of the mixing chamber and the diameter of the throat had an optimal value according to the entrainment ratio. When the length of the diffuser or throat was decreased within a range, the entrainment ratio did not change significantly.

Keywords

ejector computational fluid dynamics shockwave operating conditions geometry optimal design

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References

Mario

L. F.

Davide

Design and testing of ejectors for high temperature fuel cell hybrid systems. Trans ASME, 2006, 3, 284–291.

Zhang

and Xue, F. Experiment study and guidelines of high-pressure gas ejector. J. Therm. Sci. Technol, 2004, 3, 133–138.

Rusly

CFD analysis of ejector in a combined ejector cooling system. Int. J. Refrig., 2005, 28, 1092–1101.

Pianthong

Seehanam

Investigation and improvement of ejector refrigeration system using computational fluid dynamics technique. Energy Convers. Manage., 2007, 48, 2556–2564.

Sriveerakul

Aphornratana

Chunnanond

Performance prediction of steam ejector using computational fluid dynamics: Part 2. Flow structure of a steam ejector influenced by operating pressures and geometries. Int. J. Therm. Sci., 2007, 46, 823–833.

Li, H.J. Study of the performance, configuration and particular flow phenomena of an ejector[D]. Dalian University of Technology, Dalian, China, 2004.