Local heat-transfer and recovery temperatures of the turbulent boundary-layer with foreign-gas injection of helium, air, and Freon-12 (CCI2F2) were meas¬ured on a porous cone at cone Mach numbers 0.7;3.67 and 4.35 and in a Reynolds number range of 1 to 5 million. The heat-transfer coefficients generally show a substantial decrease of up to 80 percent from the zero-injection value for all injection gases and the relative effectiveness of the gases is in accord with theory. The recovery temperature (wall temperature for zero heat transfer to the wall) at M = 0.7, for helium injection, increases with injection to a value greater than the total stream temperature and then decreases with increased injection. At the two higher Mach numbers, for all the injection gases tested, the recovery temperature first decreases with injection then increases to values which can be greater than the total temperature of the stream. For the highest injection rates at Mach number 4.35 the heat transferred to the wall can increase with increased injection. The concept of a Stanton number and accompanying recovery factor cannot be used at the highest test injection rates to calculate the heat transfer to the wall because a recovery temperature cannot be defined. The effect of Mach number on the reduction of the heat-transfer coefficient from the zero-injection value with increase in injection rate is less than the reduc¬tion in skin friction with air injection. The heat-transfer coefficient ratios are in general agreement with the Rubesin theory heat-transfer predictions for Mach numbers from 0 to 4.35.
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