Experimental study on spray characteristics of pressure-swirl nozzle in China advanced PWR containment

Pressurized Water Reactor (PWR) is the most mature technology for nuclear power plants and nuclear power devices. Spray systems play an essential role in the safety of a PWR. The spray characteristics of the nozzle are of crucial importance for the performance of the spray system. In the present study, a test loop with four rotatable branches was established to obtain spray characteristics data, including flow characteristic, spray cone angle (SCA), spray flux distribution and droplet size spectrum. The effect of inclined angles was taken into consideration when designing and conducting the experiment. A specific type of pressure-swirl nozzle used in China advanced PWR was employed for the study. According to experimental data, variations of pressure drop and the spray angles versus volume flow rate were obtained, and typical curves of spray flux distribution were plotted, and the change in the flux distribution was evident with the change in inclined angle. The flux distribution results were used to build 3D spray flux distribution models together with the spray cone angles tested. The droplet size spectrum was measured by laser diffraction analysis. Typical droplet size distributions were obtained by the relevant software, and the experimental Probability Density Function (PDF) of droplet size was derived and compared with several empirical distributions.