An experimental investigation has been conducted to determine the film cooling effectiveness with injection of air through a discrete hole into a turbulent boundary layer of air on a flat plate. The secondary air enters at either an angle of 35 deg or an angle of 90 deg to the main flow. The film cooling effectiveness is found to be considerably different from that obtained in previous studies in which the secondary fluid was introduced through a continuous slot.

Heat transfer and pressure drop experiments were performed for in-line pin fin arrays to obtain basic data to complement available information for staggered arrays. The experimental data were utilized as input to analyses aimed at establishing performance relationships between in-line and staggered arrays. In the experiments, mass transfer measurements via the naphthalene sublimation technique were employed to determine the row-by-row distribution of the heat (mass) transfer coefficient. Fully developed conditions prevailed for the fourth row and beyond. In general, the fully developed heat transfer coefficients for the in-line array are lower than those for the staggered array, but the pressure drop is also lower. The deviations between the two arrays increase with increasing fin height. With regard to performance, the in-line array transfers more heat than the staggered array under conditions of equal pumping power and equal heat transfer area. On the other hand, at a fixed heat load and fixed mass flow rate, the staggered array requires less heat transfer surface than the in-line array.

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An experimental investigation of the interaction of a heated jet with a deflecting flow has been performed in a wind tunnel. The secondary (jet) flow is introduced at angles of 90 and 35 deg to the mainstream flow direction. Visualization studies using tufts of yarn and a carbon dioxide-water fog are reported. Temperature profiles in the interaction region are presented for blowing rates (ratio of mass flux of injected gas to mass flux of free stream) from 0.1 to 2.0 for normal injection and at blowing rates of 1.0 and 2.0 for 35 deg injection. Velocity and turbulence-intensity profiles are reported for normal injection at blowing rates of 1.0 and 2.0.