Numerical characterization of multi-nozzle spray cooling

This work aims to study the characteristics of multi-nozzle spray cooling using CFD method based on the fundamentals of air flow and liquid droplet collision dynamics. A mathematical model for the two-phase flow was presented. The simulations were performed using a Eulerian–Lagrangian approach. Focus was placed on revealing the flow behavior with multiple nozzles, the droplet trajectory, and the influencing factors. The predictions by the present simulations matched well with the experimental results available in the literature, with a comparison showing deviation below 10%. It is concluded that the multi-nozzle spray characteristics including the Sauter Mean Diameter (SMD) of droplets and the mass weighted average droplet velocity are influenced by the nozzle inlet pressure, the mass flux, the nozzle-to-surface distance and the number of nozzles. With increase of the inlet pressure, the droplet SMD decreases and the mass weighted average droplet velocity increases. With increase of the mass flux, both the droplet SMD and the mass weighted average droplet velocity increase. The nozzle-to-surface distance is a very sensitive parameter to the droplet velocity distribution. Nevertheless, the droplet velocity distribution is not a monotonic function of the nozzle-to-surface distance. With increasing nozzle number, the change in droplet size is not appreciable; whereas the mass weighted average droplet velocity decreases and the distribution of the droplet size is improved significantly.

► The characteristics of multi-nozzle spray cooling are numerical simulated.
► We examine the factors that affect the flow behavior with multiple nozzles.
► The droplet velocities decrease with the increase of the nozzle number.
► The distributions of droplet size and velocity are improved when increasing the nozzle number.