NIST Time|NIST Home|About NIST|Contact NIST

HomeAll Years:AuthorKeywordTitle2005-2010:AuthorKeywordTitle

Generalized Pressure Drop Correlation for Evaporation and Condensation in Smooth and Micro-Fin Tubes.


pdf icon Generalized Pressure Drop Correlation for Evaporation and Condensation in Smooth and Micro-Fin Tubes. (310 K)
Choi, J. Y.; Kedzierski, M. A.; Domanski, P. A.

Thermophysical Properties and Transfer Processes of New Refrigerants. IIR (International Institute of Refrigeration) Commission B1 Conference. Proceedings. October 2-5, 2001, Paderborn, Germany, B/4.9-B/4.16 pp, 2001.

Keywords:

micro-fin tubes; pressure drop; evaporation; condensation; alternative refrigerants; refrigerants; correlation; friction factor; hydraulic diameter; smooth tube

Abstract:

This paper presents a pressure drop correlation for evaporation and condensation in smooth and micro-fin tubes for lubricant-free refrigerants and refrigerant/lubricant mixtures. The form of the generalized correlation was taken from the Pierre pressure drop model. NIST micro-fin tube pressure drop data for R134a, R22, R125, R32, R407C, R410A, and R32/R134a (25/75% mass) were regressed to a modified Pierre correlation. The NIST database was post-predicted with an average absolute residual of 10.8%. Further validations performed with extensive data from the literature for lubricant-free refirgerants in smooth and micro-fin tubes showed an average absolute residual between measurements and predictions not to exceed 17.6% for the various data sets. The condensation and evaporation pressure drops for different refrigerant/lubricant mixtures werepredicted with average absolute residuals not exceeding 19.6% and 28.0%, respectively.