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Indexed by:Journal Papers

Date of Publication:2015-11-01

Journal:INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER

Included Journals:SCIE、EI、Scopus

Volume:90

Page Number:339-349

ISSN No.:0017-9310

Key Words:Microchannels; Condensation; Two phase flow; Ethanol-water mixture; Surface free energy difference

Abstract:A visualization experiment is carried out to investigate the ethanol-water vapor mixtures condensation flow patterns in an array of microchannels under a wide range of concentration (2-60%). The text microchannel is a trapezoidal silicon channel with a hydraulic diameter of 165.87 mu m and a length of 50 mm. Along the flow direction, annular, annular-streak, annular-streak-droplet, churn, injection, droplet-injection and bubble flow patterns are observed in the vapor mixtures condensation under different inlet ethanol mass concentration (60%, 31%, 20%, 6%, 4% and 2%), which is obviously different from pure steam condensation. The equivalent surface free energy differences under various vapor conditions and vapor-surface temperature differences are calculated quantitatively. The experimental results show that flow patterns are closely related to the equivalent surface free energy differences. A correlation based on the critical quality is proposed to indicate the injection two-phase flow patterns transition. (C) 2015 Elsevier Ltd. All rights reserved.