Experimental and Numerical Studies on a New Type of Spray Axial-Flow Fan

A new spray axial-flow fan with a ring-shaped spray-generating device in the upstream of the rotor is proposed in this paper. The characteristics of the new spray axial-flow fan were tested in detailed according to the international performance test standard. The experimental results showed that the characteristics of the new fan operating with working fluid which having a high water-air mass ratio have been improved obviously, compared with those of the existing spray fan with the conventional spray-generating device. The new spay fan considerably expands the limit on the water-air mass ratio of the working fluid, beyond which the motor of the spray fan may be over loaded, due to its much lower decrease slope of total pressure efficiency and much lower increment slope of shaft power against the increase in the water-air mass ratio of the working fluid. In addition, its utilization factor of sprayed water also increases obviously. Numerical investigations on this new fan with working fluid under the air phase or the mixed air-water phase were also conducted. The results indicated that the numerical results agree well with the experimental data with air as the working fluid. This verified the validity of computational models. However, the numerical results using the discrete phase model available in the Fluent program for the mixed air-water working fluid showed an evident deviation from the experimental results. The numerical simulations underestimate the deteriorating effect of the characteristics of the spay fan with water added, which means it cannot well simulate and analyze the complex flow filed inside the spay fan. Further research is needed to explore the mechanism for the deteriorated characteristics of the spray fan.