EXPERIMENTAL INVESTIGATION ON CONDENSATION HEAT TRANSFER AND PRESSURE DROP OF R22 AND R410A IN MICROTUBES

摘要

Condensation heat transfer and pressure drop of R22 and R410a were investigated experimentally in a single round stainless steel tube with the inner diameter of 0.941mm. The effects of mass flux and vapor quality were analyzed and the results indicated that local condensation coefficients increase with mass flux and vapor quality and more obviously in high vapor quality region. Comparison with Shah (1979) correlation and Akers (1959) correlation showed that both the two correlations failed to predict present experimental data accurately, especially in the high vapor quality region. Comparison between the experimental data of R22 and R410a suggested condensation heat transfer coefficients of R22 were higher than that of R410a at low mass flux and nearly equivalent at intermediate or more higher mass flux. Pressure drop of R22 was mostly much higher than that of R410a, the same as the results from available literatures on condensation heat transfer of R410a in conventional tubes.