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论文类型：期刊论文

发表时间：2017-08-01

发表刊物：INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER

收录刊物：SCIE、EI

卷号：111

页面范围：1218-1233

ISSN号：0017-9310

关键字：Micro-channel; Condensation; Slug flow; Hydrodynamic instability

摘要：This paper investigates slug flow associated with condensation along a module containing 10 of 29.9-cm long micro-channels having 1 x 1-mm(2) cross section. Using FC-72 as condensing fluid, which is cooled by water counterflow, experiments are performed to measure pressure drop as well as detailed temperature variations along the condensation module. Using high speed video, the flow is shown to consist of a series of unit cells, each comprised of a liquid slug and an elongated bubble. New interfacial instability theory is developed to describe the transition from annular flow to slug flow and obtain analytical expressions for bubble and slug lengths for the most upstream unit cell. Also presented is a new theoretical model for slug flow that is used to determine axial variations of bubble, slug and unit cell lengths. These lengths are used to evaluate axial variations of the local heat transfer coefficient, which are accurately predicted using the new model. Additionally, pressure drop data show good agreement with predictions of a recent universal correlation approach for condensation in small channels. (C) 2017 Elsevier Ltd. All rights reserved.