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Главная Архив Thermal Letter Оргкомитет Будущие конференции AIHTC
International Heat Transfer Conference 16

ISSN: 2377-424X (online)
ISSN: 2377-4371 (flashdrive)

SUBCOOLED FLOW BOILING IN NARROW MICROCHANNEL UNDER DIFFERENT ORIENTATIONS AND SURFACE WETTABILITY CHARACTERISTICS

Zengchao Chen
Department of Energy Engineering, Zhejiang University, Hangzhou 310027, China

Junye Li
Department of Energy Engineering, Zhejiang University, Hangzhou 310027, China; Co-Innovation Center for Advanced Aero-Engine, Department of Energy Engineering, Zhejiang University, Hangzhou 310027, China

Zhaozan Feng
CRRC Zhuzhou Institute Co., Ltd., Zhuzhou 412000, Hunan, China

Kan Zhou
Department of Energy Engineering, Zhejiang University, Hangzhou 310027, China

Jie Zhu
Department of Architecture and Built Environment, The University of Nottingham, Nottingham NG7 2RD, United Kingdom

Wei Li
Department of Energy Engineering, Collaborative Innovation Center of Advanced Aero-Engine, Zhejiang University, 38 Zhe Da Rd. Xihu District, Hangzhou 310027, China

Yunting Ge
RCUK National Centre for Sustainable Energy Use in Food Chain (CSEF), Brunel University London, Uxbridge, Middlesex UB8 3PH, United Kingdom

DOI: 10.1615/IHTC16.mpf.023622
pages 6511-6518


Ключевые слова: Two-phase/Multiphase flow, Boiling and evaporation, Subcooled flow, narrow microchannel, surface wettability

Аннотация

An experimental investigation of subcooled flow boiling in a high-aspect-ratio one-sided heating rectangular microchannel is conducted with hydrophilic and super-hydrophilic surfaces under different orientations utilizing deionized water as the working fluid. The super-hydrophilic surface is prepared through Plasma Enhanced Chemical Vapor Deposition (PECVD). With the inlet fluid subcooling of 10°C, the mass fluxes are in the range of 200-500 kg/(m2s) while the heat fluxes vary from 4 W/cm2 to 25 W/cm2, and the orientation angles are 0° (bottom-heated horizontal flow), 90° (vertical upflow), 180° (top-heated horizontal flow) and 270° (vertical downflow). An earlier occurrence of Critical Heat Flux (CHF) is presented for vertical downflow. With the direction of buoyancy opposite to the flow, the buoyancy impedes the departure and movement of bubbles against the inertia, causing easier bubble coalescence and elongation as well as partial dry-out process, which deteriorates heat transfer. At the mass flux of 200 kg/(m2s), the super-hydrophilic surface exhibits a delayed occurrence of CHF in the vertical orientation, while in the horizontal orientation it shows a heat transfer coefficient slightly higher by 10% for the bottom-heated flow as well as a heat transfer coefficient lower by 16% for the top-heated flow, compared with the untreated hydrophilic counterpart.

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