- Author
-
Domanski, P. A.
|
Hermes, C. J. L.
- Title
- Improved Correlation for Two-Phase Pressure Drop of R-22 and R-410A in 180° Return Bends.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD
Federal University of Santa Catarina, SC, Brazil
- Report
-
CIT06-1051,
- Book or Conf
- Brazilian Congress of Thermal Sciences and Engineering, 11th Proceedings. ENCIT 2006 Brazilian Society of Mechanical Sciences and Engineering--ABCM. Session 3: Refrigerating, Ventilation and Air Conditioning. December 5-8, 2006,
Curitiba, Brazil,
1-9 p.,
2006
- Keywords
-
pressure drop
|
experiments
|
databases
|
equations
|
correlation
|
short retrun bends
|
two-phase pressure drop
|
curvature multiplier
|
Buckinham-PI theorem
- Identifiers
- Geary's (1975) database and correlation; Chen's et al. (2004b) database and correlation; Chisholm/Idelshik Method; bend geometries tested by Chen et al. (2004b); fitted coefficients for equation (12); statistical evaluation of predictions for the 241-point database for four studied correlations
- Abstract
- A new correlation for two-phase flow pressure drop in 180° return bends is proposed based on a total of 241 experimental data points for R-22 and R-41OA from two independent studies. The data span smooth tubes with inner diameters (D) from 3.3 mm to 11.6 mm, bend radiuses (R) from 6.4 mm to 37.3 mm, and curvature ratios (2R/D) from 2.3 to 8.2. The correlation consists of a two-phase pressure drop for straight tubes and a multiplier that accounts for the bend curvature. The Buckinham-Pl Theorem was used to formulate the curvature multiplier in terms of refrigerant properties, flow characteristics, and bend geometry. The correlation predicts all data with a mean deviation of 15. 7%, and 75% of the data fall within ± 25% error bands.