Plow of refrigerant 134a through orifice tubes

In this paper; experimental data and a model for predicting refrigerant flo w through orifice tubes rued as expansion devices in automotive and other a ir conditioning systems are presented. The results are analyzed for an exte nsive set (933 data points) of measurements of mass flow rate of 1,1,1,2,-t etrafluoroethane (CH2FCF3, better known as refrigerant R-134a) through orif ice tribes of different diameters and lengths, with and without inlet and o utlet screens, over a wide range of operating conditions, and in the range of inlet qualities from 0 to 1 and subcooling rip to 40 degreesC. The mass flow rate through orifice tribes was found to be a strong function of inlet pressure, inlet subcooling, and diameter, bur a relatively weak function o f length. The semi-empirical model is developed using the data set and is a pplicable over the complete range of operating conditions covering transien ts and very high vapor quality inlets that are common in automotive air con ditioning applications.