Enhancement of flow boiling heat transfer in horizontal noncircular mini-channels and prediction of heat transfer performance

2016 Fiscal Year Final Research Report

• Project/Area Number: 26420148
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Thermal engineering
• Research Institution: Kyushu University
• Principal Investigator: MORI HIDEO 九州大学, 工学研究院, 教授 (70150505)
• Co-Investigator(Renkei-kenkyūsha): MIYATA Kazushi 九州大学, 大学院工学研究院, 助教 (00610172)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 伝熱機器 / 非円形微細流路 / 水平流 / 沸騰熱伝達促進 / 熱伝達予測方法

Outline of Final Research Achievements

Experiments were performed on two-phase flow pattern and boiling heat transfer of refrigerants R410A and R32 flowing in horizontal rectangular and triangular mini-channels with hydraulic diameter of about 1 mm, and their characteristics were clarified, compared with results for circular mini-channels, to examine the effect of flow channel geometry. In noncircular mini-channels, enhancement of heat transfer was successfully accomplished mainly with liquid film conduction evaporation at low mass flux, low quality and low heat flux in slug flow, in which thickness of liquid film around vapor plug was very thin especially on the sides of channel cross-section perimeter. Prediction of heat transfer in noncircular mini-channels was proposed considering liquid film conduction evaporation contribution in addition to nucleate boiling and forced convection evaporation heat transfers resulting even in conventional diameter channels.

Free Research Field

熱工学