Mixing of hollow-cone spray with a confined crossflow in rectangular duct

This paper presents the experimental results on the mixing of a hollow-cone spray with a confined crossflow. The experiments were carried out inside a rectangular duct (95 × 95 mmin the cross section) at the ambient temperature and pressure with different spray and crossflow conditions, different injection angles, and different nozzle numbers (single and double). The criteria number, J, which can well evaluate the spray-crossflow mixing effect was defined. A better mixing can be achieved with proper J. The upper and bottom counter-rotating vortex pair structures were observed to dominate the mixing and strongly influence the mixing behaviors. For the double nozzle, more counterrotating vortex pair structures are caused, and their sizes and strength become smaller than that of the single nozzle, which is beneficial for mixing. The spray direction along the crossflow also contributed to the mixing enhancement. The mixing optimization is realized with proper J and spray injection angles.