《A new model for depicting mass flow rate characteristic of electronic expansion valves》.pdf

Experimental Thermal and Fluid Science 32 (2007) 214–219 /locate/etfs A new model for depicting mass flow rate characteristic of electronic expansion valves Jinghui Liu *, Jiangping Chen, Qifang Ye, Zhijiu Chen Refrigeration and Cryogenics Institute, Shanghai Jiaotong University, Shanghai 200030, China Received 18 May 2006; received in revised form 15 March 2007; accepted 24 March 2007 Abstract This paper experimentally investigates the mass flow rate characteristic of an electronic expansion valve (EEV). A new model for depicting the mass flow rate characteristic of EEVs, which employs the combination of the homogeneous equilibrium fluid model (HEM) and the frozen flow model (FFM), is developed. On the basis of tested data, an equation of meta-stability coefficient is proposed. Different from the mass flow coefficient in the conventional model, the meta-stability coefficient has nothing to do with the inlet pressure and the outlet state parameters. Only the inlet sub-cooled degree and the flow area are correlated in the equation. Compared with the experimental results, the deviation of the predicted mass flow rate by the model is in the range of 8.59% to 7.56%. 2007 Elsevier Inc. All rights reserved. Keywords: Electronic expansion valve (EEV); Mass flow rate characteristic; Refrigeration; Throttling device 1. Introduction where m is the mass flow rate. A is the flow area. q1 is the density of the refrigerant at the valve inlet. P1 and P2 are Throttling device is a ve