Drift Flux Model Simulation and Experimental Investigation of the Refrigerant Flow Through Coiled Capillary Tubes

In the present study, two-phase refrigerant flow is simulated using drift flux model for straight and helical capillary tubes. The conservation equations of mass, energy and momentum are solved using the fourth order Runge-Kutta method. This model is validated by the previously published experimental, numerical results, and also by present experimental results. The effect of various conditions, such as inlet pressure, inlet temperature, sub-cooling degree, and geometric dimensions are studied. The results of our study show that for the same length and conditions, mass flux through helical capillary tube with coil diameter of 40 mm are about 10%, 15% and 20% less than in comparison of the straight tube, the helical capillary tube for coil diameter of 80 mm and 100 mm, respectively. Also, helical capillary with coil diameter of 40 mm reduces the tube length by 14%, 30% and 36% for the straight, coiled tube for coil diameter of 80 mm and 100 mm, respectively.