Numerical simulation of water spray for pre-cooling of inlet air in natural draft dry cooling towers

•Numerical investigation of inlet air cooling by water spray in NDDCTs was performed.•Strong links identified between droplet size, air velocity, evaporation and trajectory.•Pre-cooling of up to 8.1 °C predicted.•The maximum evaporation was achieved with the smallest droplet size.

This paper presents a numerical investigation of inlet air pre-cooling with water sprays to enhance the performance in Natural Draft Dry Cooling Towers (NDDCT). A 3-D numerical model of a test channel was generated and the evaporation from a single spray nozzle was analyzed. The droplet evaporation and the resulting cooling of air were predicted for a range of inlet air conditions and spray characteristics. The results showed that up to 81% evaporation can be achieved for water droplets of 20 μm at a velocity of 1 m/s and that, droplet transport and evaporation strongly depend on droplet size and air velocity.