Oblique Evaporating Sprays in Gas-Solid Suspensions

Abstract

Evaporating sprays in gas-solid flows are constantly encountered in many industry processes, such as Fluid Catalytic Cracking in petroleum industry and condensed mode operation of polyethylene polymerization in polymer industry. The rapid evaporation of droplets in a gas-solid suspension flow can have significant effects on the gas-solid mixing near the spray nozzle regions. Typical effects of evaporating jets on gas-solid dynamics include the change of velocity of gas and solids phases, dilution effect on solids concentration, temperature reduction of all phases. On the other hand, the particle loading in the gas-solid flow can also significantly change the spray structures such as spray evaporation region, evaporation rate, and collision frequency among droplets and solids. In this paper, experimental as well as theoretical studies on evaporating liquid nitrogen spray into an air-particulate suspension flow are performed. Using laser enhanced visualization system and thermocouple profile probes, we obtain the spray trajectory and temperature distribution in the test section. A comprehensive analytic model has been developed to study the parametric effects of phase interactions with phase changes in all three phases. The study shows that the particle loading can considerably affect the spray structure. Inversely, the sprays also significantly change the velocity, concentration and temperature fields of the gas-solid flow. Both qualitative and quantitative comparisons give a good agreement between experimental results and modeling simulations.