Single-Phase Cooling of Large Surface by Water Droplet Flow

Single-phase heat transfer from a vertical titanium plate with area of 140 mm2 to a water droplet flow (spray) normal to the surface of the heat exchanger was studied experimentally. Two models of commercial hydraulic full-cone nozzles with different characteristics of flow and spray pattern were used, the average mass flow rate being 2.4 kg/m2s to 6.46 kg/m2s. The maximum heat flux density of the heater was 204 kW/m2. The area-averaged heat transfer coefficient was found to be highly dependent on the mass flow rate of the coolant. The average droplet diameter and the outflow velocity from nozzle openings appear to have secondary influence on single-phase heat transfer.