A numerical study on fluid maldistribution in swirl generator distributors

Abstract

Evenly distributing the two-phase refrigerant over the paths significantly improves the evaporator's efficiency. The fluid enters the evaporator in two phases, absorbing heat from the environment and vaporizing the liquid particles. It then exits the evaporator in a single phase, completing the refrigeration cycle by moving towards the suction line. In this study, R410A at 4 degrees C was considered the working fluid. Flow analysis was performed using a commercial CFD package according to inlet conditions of 0.1, 0.2 and 0.3 quality at flow rates of 50, 75 and 100 kg/h, with the outlet pressure fixed at 806 kPa. The effects of distributors positioned vertically and horizontally on maldistribution were examined, and it was determined that maldistribution was more prevalent in horizontal distributors at low flow rates. It was suggested that swirl generators could solve the problem of maldistribution in the paths due to their centrifugal effect on the fluid. The flow then fully develops in the orifice and is distributed to the paths. The maldistribution values of the redesigned conical distributor and swirl generator distributors with swirl angles of 22.5 degrees, 30 degrees and 45 degrees under different operating conditions were then compared. The flow deviation value between the paths in the horizontal conical distributor was found to increase up to 83 %. This value decreases to 34.7 % at high flow rates. These deviation values are <10 % in swirl generator distributors. The designed swirl generator distributors are therefore a good alternative at low flow rates.