- Author
- Choi, J. Y. | Kedzierski, M. A. | Domanski, P. A.
- Title
- Generalized Pressure Drop Correlation for Evaporation and Condensation of Alternative Refrigerants in Smooth and Micro-Fin Tube.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD
- Report
- NISTIR 6333, October 1999, 67 p.
- Distribution
- AVAILABLE FROM National Technical Information Service (NTIS), Technology Administration, U.S. Department of Commerce, Springfield, VA 22161. Telephone: 1-800-553-6847 or 703-605-6000; Fax: 703-605-6900. Website: http://www.ntis.gov
- Keywords
- refrigerants | correlation | friction factor | heat transfer | hydraulic diameter | microfin tube | pressure drop | smooth tube | two-phase flow
- Abstract
- This paper presents a pressure drop correlation for evaporation and condensation in smooth and micro-fin tubes. The correlation was developed from a database consisting of the following pure and mixed refrigerants: R125, R134a, R32, R410A (R32/R125 50/50% mass), R22, R407C (R32/R125/R134a, 23/25/52% mass) and R32/R134a (25/75% mass). The new correlation was obtained by replacing the friction factor and the tube-diameter in the Bo Pierre correlation with a friction factor derived from pressure drop data for a micro-fin tube and the hydraulic diameter, respectively. The new correlation predicted the measured micro-fin data with an average residual of 10.8%, and it also predicted the pressure drop in smooth tube with an average residual of 15.0%. In addition, the correlation was used to predict pressure drop data for refrigerant/lubricant mixtures by using a viscosity-mixing rule. As a result, the new correlation predicted the measured evaporation and condensation pressure drop data for mixtures of various lubricants with R12, R22, and R134a with an average residual of 19.0%.