Generalized Pressure Drop Correlation for Evaporation and Condensation of211 Alternative Refrigerants in Smooth and Micro-Fin Tubes

摘要

This paper presents a pressure drop correlation for evaporation and condensation211u001ein smooth and micro-fin tubes. The correlation was developed from a database 211u001econsisting of the following pure and mixed refrigerants: R125, R134a, R32, R410A 211u001e(R32/R125 50/50 % mass), R22, R407C (R32/R125/R134a, 23/25/52 % mass) and 211u001eR32/R134a (25/75 % mass). The new correlation was obtained by replacing the 211u001efriction factor and the tube-diameter in the Bo Pierre correlation with a 211u001efriction factor derived from pressure drop data for a micro-fin tube and the 211u001ehydraulic diameter, respectively. The new correlation predicted the measured 211u001emicro-fin data with an average residual of 10.8 %, and it also predicted the 211u001epressure drop in smooth tube with an average residual of 15.0 %. In addition, the 211u001ecorrelation was used to predict pressure drop data for refrigerant/lubricant 211u001emixtures by using a viscosity-mixing rule. As a result, the new correlation 211u001epredicted the measured evaporation and condensation pressure drop data for 211u001emixtures of various lubricants with R12, R22, and R134a with an average residual 211u001eof 19.0%.