Numerical simulation and experimental analysis of refrigerants flow through adiabatic helical capillary tube

• For first time, drift flux model was applied for refrigerant flow simulation through helical capillary tubes.
• This pioneer model is reliable tools for designing and optimization of VCRC for straight or helical capillary tubes.
• Experimental validation confirms the numerical results with maximum deviation of 5.5%.
• By increasing coil diameter of the capillary tube, mass flux is increased in same length and conditions.
• Helical capillary tube length with coil diameter of 40 mm is about 14% shorter than straight one for same mass flux.

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 4th order Runge–Kutta method. This model is validated by previously published experimental and numerical results and also by experimental results presented in this work. The effect of various parameters such as inlet pressure, inlet temperature, sub-cooling degree, and geometric dimensions are studied. The results of the present study show that for the same length and under similar conditions, mass flux through helical capillary tube with coil diameter of 40 mm are about 11% less than that through the straight tube, where the helical tube length is about 14% shorter than the straight one for the same refrigerant mass flux.