Experimental and numerical study of Y-jet nozzle of LN₂-spray temperature-adjusting system

Based on Euler-Lagrange method, the characteristic of LN₂ (liquid nitrogen) atomized by the Y-jet nozzle was studied by discrete phase model and air blast atomizer model of software FLUENT. Because of the evaporation effect of LN₂ droplets, the spray angle was about 10°, significant smaller than the spray angle of water, and the spray distance was shortened. The effect of operating pressure on the Sauter mean diameter (SMD) and the distribution of volume fraction and quantity percentage was analyzed. The results indicate that the SMD along the spray direction is essentially unchanged. The SMD is controlled by gas velocity and gas-liquid ratio, and gas velocity is the major factor in the low pressure conditions while gas-liquid ratio is the major factor in the high pressure conditions. The distribution of LN₂ droplets diameter is more concentrated than in the cases using water, due to the evaporation of droplets. The effect of temperature control of LN₂-spray temperature-adjusting system using Y-jet nozzles with different flow rate demands was also investigated. The temperature of outlet was lower than 98 K with temperature difference of 12 K between inlet and outlet, and the temperature difference of outlet was within ±1 K, which could satisfy the temperature control requirements.