Effect of shock waves on supersonic film cooling with a slotted wall

• Slotted wall improves the film cooling after the shock wave.
• 2D coolant motion is well modeled by the numerical mesh in and out the slots.
• Geometrical parameters of the slots providing the best cooling effectiveness are identified.

A slotted wall with a cavity which reduces the effect of the shock wave on the film cooling was developed through understanding of the mechanism by which the shock wave affects the supersonic film cooling. Numerical results show that the supersonic film cooling effectiveness with the slotted wall is improved after the shock wave incidence, even better than that without the shock wave effect. The cooling stream flows into the cavity upstream of the slotted wall and flows out downstream, which bypasses more cooling gas to protect the surface downstream after the shock wave incidence, which weakens the effect of the shock wave on the film cooling. Upstream of the shock wave incidence, the slotted wall reduces the mixing between the mainstream and the cooling stream and the coolant boundary layer thickness, which reduces the film cooling effectiveness for both structures than without the slotted wall, with an effectiveness which nearly the same as or even a little better than without the slotted wall for another structure.