Experimental investigation of full-coverage effusion cooling through perforated flat plates

• Effusion cooling using perforated plate was investigated experimentally.
• The effect of cooling hole diameter was investigated.
• The cooling efficiency results were close to that of transpiration cooling.

The flow and heat transfer mechanisms of perforated plate effusion cooling with hole diameters of d = 1 mm and 0.5 mm were investigated experimentally. The effects of injection rate and hole diameter on the exterior surface temperature distribution were studied using an IR imaging system. A particle image velocimetry (PIV) measurement system was also used to qualitatively study the turbulent boundary layer development and the interactions between the mainstream and the coolant flow. The surface temperature contours showed that for all the injection rates in the present study, the coolant generated a uniform protective film on the wall. When the blowing ration was high (F = 2%∼2.5%), the cooling efficiency of perforated plate with d = 1 mm holes was much lower than that of d = 0.5 mm case because of the strong mixing and impulse in the boundary layer. And the cooling effectiveness of the full coverage effusion cooling with densely arranged d = 0.5 mm cooling holes (ε = 19.6%) could be nearly the same with transpiration cooling with sintered porous flat plate (ε = 36%).