R-32, Electronic Expansion Valve, Capillary Tube, Throttling Model
The mass flow rate of R-32 and volumetric flow rate of dry air in an electronic expansion valves(EEV) , in two different capillary tubes(CT) and in one expansion valve in series with two different capillary tubes were tested, and the theoretical volumetric flow rate of dry air in one EEV in series with different CTs were predicted through a theoretical throttling model built in this paper. The results showed that the mass flow rate of R-32 or volumetric flow rate of dry air of the serial throttling component was lower than but close to that of the EEV in low openings and that of the CT in full opening, respectively, under the same operating conditions. The flow rate ratio of the serial throttling component to the EEV decreased fast with opening increasing, and the flow rate ratio of the refrigerant was obviously lower than that of the dry air. The refrigerant mass flow rate of EEV in series with CT up flow was higher than that of the same EEV in series with the same CT down flow.