Experimental Study on Particle Deposition of Plate Surface with Film Cooling

In order to understand the deposition regularity of particulate matter on the surface of the turbine blade and the effects of deposition on the cooling of the film, the wax particles was sprayed into small wind tunnel by wax spraying apparatus in this experiment.The wax was deposited on the surface of the plate with film cooling to simulate the deposition process of the particles on the turbine blades.The Stokes number, which characterized the size of the wax melting particles, was matched with the particles of coal ash in the actual gas turbine engine.By adjusting the mainstream temperature, the wax particles were kept in a molten state before deposition to simulate the adhesion of the particles on the real turbine blades.The effects of different blowing ratios and different injection angles on the deposition of wax and the effects of wax deposition on the film cooling of the flat surface were observed in the process of wax deposition with and without film cooling.It was found that when the melting temperature of paraffin wax is close to the mainstream temperature, it is easier to deposit on the surface of the plate, and the paraffin deposition does not increase after growing to a certain thickness.In the case of film cooling, when the blowing ratio increases from 0 to 1.5, the deposition of wax on the surface of the flat plate decreases first and then increases, and the deposition of wax is the least when the blowing ratio is 0.5.With the injection angle increased from 30° to 90°, the deposition of wax on the plate surface gradually increases.Wax deposition reduces the cooling effectiveness of the flat membrane, and the temperature of the downstream region between the film holes is higher than that of the downstream region of the film holes. © 2018, Editorial Department of Journal of Propulsion Technology. All right reserved.