A new model for depicting mass flow rate characteristic of electronic expansion valves

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%.