A coupled discrete droplet and SPH model for predicting spray impingement onto surfaces and into fluid pools

•A combined DEM-SPH model is developed for spray impingement into a pool of liquid.•Momentum and mass are transferred from the discrete spray into the fluid phase.•The model is evaluated using experimental pressure measurements for 1–3 sprays.•Comparison of pressure predictions with experiment shows very good agreement.•Collisions of droplets from different sprays have a small but noticeable effect. In this paper we detail the development of a combined DEM-SPH model for spray impingement into a pool of water or onto a flat surface on which a pool of water can build up. The spray is represented by discrete particles which can collide with solid objects, each other and also merge with liquid surfaces. The liquid pool dynamics are solved for using the SPH method. The proposed coupling allows momentum to be transferred from the discrete spray phase into the fluid phase in the pool. The performance of this coupled DEM-SPH method is evaluated by comparing to experiments performed for simple spray arrangements in which the pressure in the pool just above the solid surface is carefully measured by a probe that is moved systematically across the surface. A comparison of the simulated pressure distribution with those from the experiments shows very good agreement for the size of the high pressure region, the average pressure the pressure distribution within this region generated by the spray impingement for cases with one, two and three overlapping sprays. Collisions between spray droplets in the case of multiple sprays are found to have a small but noticeable effect on the details of the high pressures in the regions of overlap of the sprays.