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An experimental study on explosive boiling of superheated droplets in vacuum spray flash evaporation

Lookup NU author(s): Dr Dawei WuORCiD



This is the authors' accepted manuscript of an article that has been published in its final definitive form by Elsevier Ltd, 2019.

For re-use rights please refer to the publisher's terms and conditions.


© 2019 Elsevier LtdSpray flash evaporation is an effective desalination method, which increases specific surface area of salty water by liquid atomization, thereby improving desalination performance and maximising low-grade heat source utilization. During evaporation, explosive boiling phenomenon occurs inside superheated droplets on a heated surface. In order to understand the mechanism of explosive boiling, spray flash evaporation of distilled water and 3.5 wt% salty water in a high vacuum vessel was observed visually. Meanwhile, a parametric study was carried out to scrutinize the impacts of the variation of ambient pressure, heat flux, and surface superheat degree. The experiment data indicates that nucleate site is located in the upper layer of a droplet due to internal superheated liquid and Marangoni convection. In different operating conditions, bubble fragmentation process or crown fragmentation process happens at nucleate site. The fragmentation time of pure water, which is mainly influenced by heat flux and surface superheat degree, shrinks with higher heat flux and higher surface superheat degree. The fragmentation time of 3.5 wt% salty water decreases with ambient pressure drops and superheat degree increments.

Publication metadata

Author(s): Gao W, Qi Q, Zhang J, Chen G, Wu D

Publication type: Article

Publication status: Published

Journal: International Journal of Heat and Mass Transfer

Year: 2019

Volume: 144

Online publication date: 30/08/2019

Acceptance date: 07/08/2019

Date deposited: 23/10/2019

ISSN (print): 0017-9310

Publisher: Elsevier Ltd


DOI: 10.1016/j.ijheatmasstransfer.2019.118552


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