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