Effect of spray angle on mixing of evaporating spray in crossflow

The influences of spray angle on the mixing of evaporating spray droplets in the crossflow were investigated via a numerical simulation to obtain the optimum spray angle that leads to an enhanced mixing and an improved cooling effect. An evaluation criterion for mixing effect and degree of mixedness, was proposed. Based on the well validation with the experiment, the distributions of crossflow temperature, flowfield structures and curve of mixing degree under five spray angles of 40°, 60°, 80°, 90° and 100° were numerically obtained. The results show that the cooling effect increases with the increase of spray angle, while the mixing degree reaches the maximum when the spray angle is 90° and then decreases with the continuous increase of spray angle. The symmetrical vortex pairs under the small spray angle contribute to the mixing in certain regions. However, an improved mixing uniformity can be achieved with a larger spray angle attributed to the multi-scale vortex pairs. The spray angle within the range between 90° and 100° is preferred in terms of both the mixing degree and the cooling effect.