Ejector primary nozzle steam condensation: area ratio effects and mixing layer development

Ariafar, Kavous and Buttsworth, David and Sharifi, Navid and Malpress, Ray (2014) Ejector primary nozzle steam condensation: area ratio effects and mixing layer development. Applied Thermal Engineering, 71 (1). pp. 519-527. ISSN 1359-4311

Abstract

Recent ejector simulations based on wet steam modeling give significantly different performance figures relative to ideal gas modeling, but the origins of such differences are not clear. This paper presents a numerical investigation of flow in the primary nozzle of a steam ejector to further explore the differences between ideal gas and wet steam analysis of ejector flows. The wet steam modeling was first validated using primary nozzle surface pressure data from three experiments reported in the literature. Ejector primary nozzles with area ratios (AR) of 11, 18 and 25 were then simulated using wet steam and ideal gas models. The wet steam simulations show that nozzle static pressures are higher than those for ideal gas model, and in the AR = 25 case, the static pressure is larger by a factor of approximately 1.7. In contrast, no significant difference exists between the nozzle momentum flux for both ideal gas and wet steam models, except the vicinity of the nozzle throat where nucleation occurs. Enhanced mixing between primary and secondary streams, which arises because primary stream condensation reduces compressibility in the mixing layer, is proposed as an explanation of the increased entrainment ratio observed in recent wet steam ejector simulations.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: © 2014 Elsevier Ltd. Permanent restricted access to published version in accordance with the copyright policy of the publisher.
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Mechanical and Electrical Engineering
Date Deposited: 14 Aug 2014 23:35
Last Modified: 04 Jul 2016 06:35
Uncontrolled Keywords: CFD; mixing; nozzle; nucleation; steam condensation; steam ejector
Fields of Research : 09 Engineering > 0915 Interdisciplinary Engineering > 091508 Turbulent Flows
09 Engineering > 0915 Interdisciplinary Engineering > 091501 Computational Fluid Dynamics
09 Engineering > 0913 Mechanical Engineering > 091307 Numerical Modelling and Mechanical Characterisation
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970109 Expanding Knowledge in Engineering
Identification Number or DOI: 10.1016/j.applthermaleng.2014.06.038
URI: http://eprints.usq.edu.au/id/eprint/25773

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