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ISSN Online: 2377-424X

International Heat Transfer Conference 12
August, 18-23, 2002, Grenoble, France

Condensation of Superheated R134a Vapor inside Horizontal Smooth and Three-dimensional (3-D) Microfin Tubes

Get access (open in a dialog) DOI: 10.1615/IHTC12.5380
6 pages

Abstract

For steady, laminar, filmwise condensation of superheated vapor in a horizontal smooth tube it is found that the superheated vapor condensation is governed by seven parameters. These are the ratio of vapor Froude to Reynolds number Fro/Reo, liquid Prandtl number Prl, Buoyancy number Bo (= 1− ρvl), vapor to liquid viscosity ratio µ* (= µvl), vapor to liquid Prandtl number ratio Pr* (= Prv/Prl), vapor to liquid heat conductivity ratio k* (= kv/kl) and Subcooling number So (= Cpl(Tsat−Tw)/hlv) A numerical solution of the resulting set of equations for refrigerant R134a superheated vapor was conducted. On the given condition, the curve of R134a superheated temperature against the vapor qua lity has been obtained. The superheated temperature vanishes at x=0.53.

An experimental investigation of R134a superheated vapor condensation inside a horizontal smooth tube and three-dimensional (3-D) microfin tubes was also performed. The experimental data indicate that the temperature of superheated vapor decreases rapidly with the vapor quality in the region near the inlet of tube. In the experimental conditions, the vapor qualities x corresponding to the disappearing of superheated temperature are larger than 0.8. When taking (Tsat-Tw) as the temperature difference of superheated vapor condensation heat transfer, the coefficients of superheated vapor can be calculated by using Webb's approach. The dispersities of the regressed correlation are within ±15%.