Heat transfer near injection hole by shock and boundary layer interaction in the supersonic flow field

The flow structure and heat transfer coefficient are investigated using both experimental and numerical methods in the supersonic flowfield with transverse jet injection. The geometry of this research is an expansion nozzle with injection hole. The diameter of injection jet hole is 8.8 mm. The supersonic flow facility used in this research is the intermittent supersonic blow down tunnel. The expansion ratio of nozzle (A/A∗) has 4.23 at the outlet and 3.56 at the injection location. Selected jet-to-freestream momentum flux ratio is J = 0.5, 1.0 and 1.3 to verify the variation related to the momentum ratio near J = 1.0 which is common momentum ratio for secondary injection system. Flow structure with shock interaction at the surface is visualized by oil-lampblack and numerical simulation. Heat transfer on the surface is measured by IR thermography using transient method. Results show that the first separation point moves to the adverse direction of flow with increasing jet-tofreestream momentum ratio. Also, the peak value of heat transfer increases and moves farther from jet location due to penetration of transverse jet. These results will serve as fundamental database for thermal design of transverse jet.