Experimental investigation of effervescent atomization: Part II. Internal flow and spray characterization with novel DARPA SUBOFF afterbody streamline aerator

Niland, Andrew, Santhosh, R., Marsh, Richard ORCID: https://orcid.org/0000-0003-2110-5744 and Bowen, Philip ORCID: https://orcid.org/0000-0002-3644-6878 2022. Experimental investigation of effervescent atomization: Part II. Internal flow and spray characterization with novel DARPA SUBOFF afterbody streamline aerator. Atomization and Sprays 32 (4) , pp. 25-51. 10.1615/AtomizSpr.2022039408

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Abstract

In this experimental work we report, for the first time, observations of internal flow field involving an DARPA SUBOFF afterbody design aerator body in an inside-out type of effervescent atomizer. The effect of operating parameters like air-to-liquid ratio (ALR), operating pressure, aerator orifice diameter, aeration area and mixing chamber diameter on internal flow within the effervescent atomizer is studied. The effect of increasing ALR on the internal flow is quantified by identifying different gas injection mechanisms at the aerator orifice (into the mixing chamber) and two-phase mixing chamber flow regimes. In particular, it is observed that as ALR is systematically increased the gas injection mechanism transits in the following sequence: single bubbling, pulsed bubbling, elongated jetting, atomized jetting and evacuated chamber. The range of ALRs within which these mechanisms are observed are employed to draw up a flow regime map. Similar analysis on two-phase mixing chamber flow regimes yielded corresponding regime map for internal two-phase stabilized flow in the mixing chamber. The flow regime transited from bubbly flow to slug flow to churn flow and finally to annular flow as the ALR was increased. Dependence of internal flow on other parameters such as orifice aerator diameter (with constant total aerator orifice area), mixing chamber diameter and operating pressure are also studied.

Item Type:	Article
Date Type:	Published Online
Status:	Published
Schools:	Engineering
Publisher:	Begell House
ISSN:	1044-5110
Date of First Compliant Deposit:	25 November 2021
Date of Acceptance:	27 October 2021
Last Modified:	07 Nov 2023 19:49
URI:	https://orca.cardiff.ac.uk/id/eprint/145746

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