Modelling the bleed port of a thermostatic expansion valve

This article presents a model to predict refrigerant flow rate through the bleed port of a thermostatic expansion valve using a separated flow model. Four types of inlet/outlet conditions: liquid/liquid; liquid/two-phase; two-phase/two-phase; and vapour/vapour are studied. Refrigerant flow rate predictions of the model are compared to measured data. The results of this comparison show that the model is within ±20% for 95% of the experimental data corresponding to either an inlet fluid in a sub-cooled or a two-phase state. When the inlet fluid is in a vapour state, the model is able to predict 96% of the experimental data within ±16%.