Studies on the effects of varying secondary gas properties in a low entrainment ratio supersonic ejector

Rao, Srisha MV and Jagadeesh, G (2015) Studies on the effects of varying secondary gas properties in a low entrainment ratio supersonic ejector. In: APPLIED THERMAL ENGINEERING, 78 . pp. 289-302.

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Abstract

A dilution cum purge ejector for application in fuel cells represents a domain of ejector operation involving low entrainment ratio with differing secondary and primary gas; which is hardly investigated and a cohesive design framework is not readily available. We comprehensively study a constant area ejector using analytical, experimental and numerical tools at low entrainment ratio (0.004-0.065) with Air, Helium and Argon as secondary gas while the primary gas is Air. For the first time, limits of operating parameters used in control volume method to design the ejector are found to be highly dependent on the secondary molecular weight. The entrainment ratio in the ejector (low for Helium and high for Argon) is affected by the molecular weight and the static pressure within the ejector (low for Air and high for Argon & Helium) by the gamma of the secondary gas. Sufficient suction pressure (0.3-0.55 bar) is generated by the ejector thereby preventing any backflow of secondary gas at all primary stagnation pressures (1.5, 2.2 and 3.1 bar). Numerical results agree well with experimental results. The ejector is shown to completely dilute and purge the secondary flow, meeting all key design requirements. (C) 2014 Elsevier Ltd. All rights reserved.

Item Type:	Journal Article
Publication:	APPLIED THERMAL ENGINEERING
Publisher:	PERGAMON-ELSEVIER SCIENCE LTD
Additional Information:	Copy right for this article belongs to the PERGAMON-ELSEVIER SCIENCE LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND
Keywords:	Supersonic ejector; Dilution cum purge ejector; Fuel cells; Secondary gas properties; Control volume method; Gaseous mixing
Department/Centre:	Division of Mechanical Sciences > Aerospace Engineering(Formerly Aeronautical Engineering)
Date Deposited:	20 Apr 2015 06:55
Last Modified:	06 May 2015 09:27
URI:	http://eprints.iisc.ac.in/id/eprint/51220

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