Numerical study on mixing of spray and gas crossflow with high temperature

In a confined space with high pressure and temperature, the mixing characteristics of pressure-swirl spray in the crossflow are unclear. In this work, the mixing process of pressure-swirl spray in the overheated gas crossflow in a pipe was studied numerically. In order to put forward proper method to enhance mixing efficiency, flow behaviors and mixing regularities were investigated here. The results show that spray droplets swarm can fill up the mixing space uniformly with four nozzles equally distributed on circumference. At the central regions between each two adjacent nozzles, the concentration of droplets swarm is high and the temperature is low. Near the pipe wall, pairs of vortices with small scale occur. The evolution of vortices with small scale is the main way to improve droplets evaporation and uniform mixing. Spray angles, axial injection angles and tangential injection angles of nozzles have significant influences on the droplets residence time and depth of penetration. Hence, those angles play important roles on the mixing efficiency. A favorable mixing can be achieved with appropriate spray angle, axial injection angle and tangential injection angle of spray nozzles.