Short Duration Heat Transfer Studies at High Free-Stream Temperatures

Abstract

This paper describes short duration heat transfer measurements on a flat plate and a gas turbine nozzle airfoil at high free-stream temperatures. A shock tube generated the high-temperature and pressure air flow. Thin-film heat gages recorded the surface heat flux. The flat plate was tested both in the shock tube and in a shock tunnel placed aft of the tube. Shock tunnel tests on the nozzle airfoil measured the local heat transfer distribution. The flat plate free-stream temperatures varied from 830°R (460 K) to 3190°R (1770 K) for a Tw /TT, g temperature ratio of 0.17 to 0.64 at Mach numbers from 0.12 to 1.34. The nozzle measurements at a Tw /TT, g of 0.35 to 0.39 generally indicate that pressure (concave) surface heat transfer coefficients are high, whereas the suction (convex) surface shows much lower heat transfer coefficients than a turbulent flat-plate correlation.