An assessment of friction factor and viscosity models for predicting the refrigerant characteristics in adiabatic capillary tubes

마찰 계수와 점성 계수 모델이 단열 모세관 유동에 미치는 영향 평가

Capillary tubes are widely used as expansion device in small refrigeration systems. The refrigerant flowing in the capillary tube experiences frictional and accelerational head losses, and flashing, simultaneously. In this paper flow characteristics of adiabatic capillary tubes with various friction factor models, two-phase viscosity models, and two-phase frictional multiplier models were simulated. The predicted pressure distribution, mass flow rate are compared with experimental data reported in literature. It is confirmed that the predicting accuracy with homogeneous model can be improved by employing the suitable correlations of friction factor and two-phase viscosity model, and two-phase frictional multiplier.