Dimensionless local and average boiling heat transfer correlation for saturated liquids

Abstract

The present study is an experimental investigation on nucleate pool boiling of saturated liquids namely, distilled water, methanol, and isopropanol over a plain copper heating tube at atmospheric and sub-atmospheric pressures. The study includes the effect of operating parameters, i.e., heat flux and pressure on the boiling heat transfer coefficient of saturated liquids on a copper heating tube. The boiling heat transfer coefficient is determined locally at the bottom, two sides and at the top position of the heating tube and a dimensionless equation of the form h?* h ?,1* = [(a + b cos ?)/(a + b cos ?) 1 (p/p1)0.32 is established for prediction of the local boiling heat transfer coefficient at different pressures. Further, a dimensional equation, h = Cq0.7p0.32, is established for determination of the average boiling heat transfer coefficient of saturated liquids on a plain copper heating tube. The dimensionless correlations of earlier investigators are tested with experimental data of the present investigation for the sake of comparison. Further, a dimensionless correlation of the form: NuB* = Csf(Pe B*)0.7 (Kp)0.7 (Pr)-0.67 is proposed. The correlation is found to fit experimental data of the present investigation within a maximum error of ±6.