Experimental data were taken to examine R-410A mass flow rate characteristics through short tube restrictors at upstream pressures approaching the critical point. Four short tube restrictors were tested by varying upstream pressure from 2619 to 4551 kPa (corresponding to saturation temperature from 43.9 to 71.7 °C), upstream subcooling from 2.8 to 11.1 °C and downstream pressure from 772 to 1274 kPa. The experimental data were represented as a function of major operating parameters and short tube diameter. As compared to mass flow trends at typical upstream pressures, flow dependency on upstream subcooling was more significant at high upstream pressures due to a higher density change. Based on the database obtained from this study and literature, an empirical correlation was developed from a power law form of dimensionless parameters generated by the Buckingham Pi theorem. The post-predictions of the new correlation yielded average and mean deviations of 0.11 and 2.4%, respectively.
Bibliographical noteFunding Information:
This study was supported by the National Institute of Standards and Technology, Gaithersburg, MD, USA and the Korea University, Seoul, South Korea.
Copyright 2008 Elsevier B.V., All rights reserved.
- Critical point
ASJC Scopus subject areas
- Building and Construction
- Mechanical Engineering