Study on heat transfer and flow characteristics of environment-friendly mixtures in plate type evaporators

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K13935
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 24020:Marine engineering-related
• Research Institution: Tokyo University of Marine Science and Technology
• Principal Investigator: JIGE DAISUKE 東京海洋大学, 学術研究院, 准教授 (30708368)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: プレート式蒸発器 / 蒸発熱伝達 / 可視化 / 流動様相 / 混合冷媒 / IRカメラ

Outline of Final Research Achievements

In this study, the evaporation heat transfer and flow characteristics of lower-GWP refrigerants such as hydrofluoroolefins (HFOs) and HFO/HFC mixtures in plate-fin heat exchangers were experimentally investigated. This study visualized adiabatic and evaporation flows and measured evaporation heat transfer coefficients using the test evaporator comprising a refrigerant channel and heat-source water channels. The temperature distributions of zeotropic refrigerant mixtures in the width- and flow-directions of the channel owing to the asymmetry of the inlet and outlet of the channel were also measured using an IR camera. The effects of the vapor quality, mass velocity, heat flux, and circulation composition on the evaporation heat transfer and flow characteristics were clarified.

Free Research Field

熱工学，船舶海洋工学

Academic Significance and Societal Importance of the Research Achievements

温室効果ガス排出抑制の観点から，環境負荷の小さい次世代冷媒の開発とそれに適応した機器の開発が望まれている．プレート式熱交換器は単位体積あたりの伝熱面積が大きく，熱交換器の小型化による冷媒充填量の削減が期待できるが，流路の出入口が非対称であり，アスペクト比の大きい流路から構成されるため，流路内で複雑な熱伝達および流動特性を示す．本実験では地球温暖化係数の小さいHFO系冷媒とその混合物について，蒸発器の流路幅方向および流れ方向に変化する蒸発熱伝達および蒸発流動特性を実験的に明らかにした．得られた成果は次世代冷媒に適応した熱交換器の高性能化への貢献が期待できる．