A study on reduction of aerodynamic heating load by film cooling

Aerodynamic heating due to heat protection problems due to film cooling on blunt bodies are experimentally and computationally investigated. Experiments are conducted by using a conventional shock tunnel. Testing conditions are at freestream Mach number M = 4.25, P₀ = 0.45 ~ 0.60 MPa, T₀ = 408 ~ 449 K and Reynolds number = 4.4 ~ 5.4 × 10⁵. For the experiments on heat protection with film cooling a semi-sphere model is used and at 24 degrees location from the top of the model a cooling air is supplied through slot. In the experiments two ways of mass bleeding of tangential and normal directions from the model surface have been conducted and the results with both directions are compared. In the both directions significant decreases of surface heat flux have been obtained and tangential mass bleeding is proved to be more effective on heat protection. The results show the mass addition is quite significant in reducing aerodynamic heating at the nose of the blunt body. Also numerical simulations on heat protection with film cooling have been conducted. As the mass flow rate is increased, surface heat flux is reduced. The results show good agreements with experiments qualitatively.