Effect of Pore Size on The Nucleate Pool Boiling of Structured Enhanced Tubes

• Published in: Journal of thermal science 2000-09, Vol.9 (3), p.230-235
• Main Authors: Kim, Nae-Hyun, Kim, Jong-Won, Kim, Tae-Hyung
• Format: Article
• Language: English
• Subjects: 成核沸腾; 毛细效应
• ISSN: 1003-2169; 1993-033X
• DOI: 10.1007/s11630-000-0056-4

In this study,pool boiling test results are provided for the structured enhanced tubes having pores with connecting gaps.The surface geometry of the present tube is similar to that of Turbo-B.Three tubes with different pore size (0.20mm,0.23mmand 0.27mm) were manufactured and tested using R-11,R-123 and R-134a.The pore size which yields the maximum heat transfer coefficient varied depending on the refrigerant.For R-134a,the maximum heat transfer coefficient was obtained for the tube having 0.27mm pore size.For R-11 and R-123,the optimum pore size was 0.23 mm.One novel feature of the present tubes is that their boiling curves do not show a corss-over characteristic,which existing pored tubes do.The connecting gaps of the present tube are believed to serve an additional route for the liquid supply and delay the dry-out of the tunnel,The present tubes yield the heat transfer coefficients approximately equal to those of the existing pored enhanced tubes.At the heat flux 40kW/m2 and saturation temperature 4.4^0 C,the heat transfter cofficients of the present tubes are 6.5 times larger for R-11,6.0times larger for R-123 and 5.0 times larger for R-134a than that of the smooth tube.