冷媒R1234ze(E),R1234ze(Z),R134a およびR245fa の水平平滑円管上の自由対流凝縮およびプール沸騰熱伝達特性

Translated title of the contribution: Condensation and Pool Boiling Heat Transfer Characteristics of R1234ze(E), R1234ze(Z), R134a and R245fa on a Horizontal Plane Tube

永田 龍一, 近藤 智恵子, 高田 信夫, 小山 繁

    Research output: Contribution to journalArticlepeer-review

    Abstract

    In this study, condensation and pool boiling heat transfer characteristics of R134a, R1234ze(E), R245fa and R1234ze(Z) are investigated experimentally on a horizontal plane tube. The test tube of outer diameter and heat transfer length are 19.12 mm and 400 mm, respectively. For the condensation at saturation temperatures from 20 to 60 °C and the degrees of wall subcool from 0.77 to 28.81 K, the measured condensation heat transfer coefficient of R1234ze(Z) agree with that of Nusselts filmwise condensation theory within approximately ±11 %. The condensation heat transfer coe<sub>o </sub>fficient of R1234ze(Z) is slightly higher than <sub>-2 </sub>other refrigerants. For pool boiling at saturation temperatures from 10 to 60 C and heat fluxes from 0.73 to 80.13 kWm , the measured pool boiling heat transfer coefficients reasonably agree with that predicted by Stephan-Abdelsalam correlation. The pool boiling heat transfer coefficie<sub>o </sub>nts of R1234ze(E) and R134a <sub>-2 </sub>are significantly higher than those of R1234ze(Z) and R245fa at saturation temperature 20 C and heat flux 15 kWm . However, the pool boiling heat transfer coefficient of R1234ze(Z) becomes larger with increasing the reduced pressure.
    Translated title of the contributionCondensation and Pool Boiling Heat Transfer Characteristics of R1234ze(E), R1234ze(Z), R134a and R245fa on a Horizontal Plane Tube
    Original languageJapanese
    Pages (from-to)439-449
    Number of pages11
    Journal日本冷凍空調学会論文集
    Volume31
    Issue number4
    DOIs
    Publication statusPublished - 2014

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