Numerical Study on the Application of Pressure-Swirl Atomizing Nozzles in a Direct Air Cooling Condenser of the Power Plant

In this paper, a pressure-swirl atomizing nozzle was proposed to improve the atomization characteristics and enhance the heat transfer characteristics. By modifying the structural parameters of the nozzle, the effect of angles of inclined holes on the swirl plate on the heat transfer characteristics was studied, and the structure of the nozzle was optimized based on fluent software. The corresponding relationship between the pressure difference between the inlet and outlet of the nozzle and the flowrate was obtained, which provides a basis for the parameter setting of the discrete phase model. The nozzle was then applied to a spray humidification system of a direct air cooling unit in the power plant. The influences of nozzle arrangements and spray directions on the vacuum degree of the system were studied. The results of the numerical study show that the nozzle with the angle of inclined holes at 45 deg not only has the highest heat transfer efficiency but also has the highest heat transfer uniformity among all the simulated cases. In the air cooling unit of the power plant, when the nozzles are arranged in staggered rows and the angle between the spray direction and the positive direction along the height is kept at 15 deg, the heat transfer performance of spray humidification is the best. The vacuum degree of the condenser is the highest.