Study on the Characteristics of condensation in the transition region of the non-azeotropic refrigerant mixture

2015 Fiscal Year Final Research Report

• Project/Area Number: 25420150
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Thermal engineering
• Research Institution: The University of Tokyo
• Principal Investigator: Dang Chaobin 東京大学, 新領域創成科学研究科, 准教授 (30401227)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: flow pattern / microchannel / film thickness / slug flow / condensation / laser measurement

Outline of Final Research Achievements

In-tube condensation characteristics are closely related to the liquid film thickness in the vicinity of the wall and its turbulence. A precise measurement of the behavior of thin liquid film during condensation is crucial to understand the phase-transition process. Furthermore, it is important to investigate the effect of the shape of the heat transfer tube, dimensions, surface characteristics, and thermophysical properties of the working fluid (density, viscosity and surface tension) on the the thin liquid film behavior.
In this study, direct measurement of the behavior of thin film of five types of different working fluids were tested inside a small sized glass tube with inner diameter ranging from 0.5 mm to 2 mm by using a laser confocal displacement sensor successfully. The relationship of averaged value and transient variation of film thickness with the structure and geometry of the test tube, flow parameters and surface properties (hydrophilic, hydrophobic) were elucidated.

Free Research Field

熱工学