Heat Transfer, Adiabatic Effectiveness and Injectant Distributions Downstream ofSingle and Double Rows of Film-Cooling Holes with Compound Angles

摘要

Experimental results are presented which describe the development and structureof flow downstream of one row and downstream of two staggered rows of film cooling holes with compound angle orientations. Results presented include distributions of iso-energetic Stanton number ratios, and adiabatic film-cooling effectiveness deduced from Stanton numbers using superposition. Also presented are plots showing the streamwise development of injectant distributions and streamwise development of mean velocity distributions. Spanwise averaged values of the adiabatic film-cooling effectiveness are highest for blowing ratio m=0.5 and decrease as blowing ratio increases for x/d less than 20. At farther downstream positions, spanwise averaged effectiveness values increase with blowing ratio, except for data obtained downstream of two rows of holes with a blowing ratio of 3.0 and data obtained downstream of two rows of holes with a blowing ratio of 3.0 and data obtained downstream of one row of holes with a blowing ratio of 4.0, where severe lift-off of injectant occurs. Spanwise averaged iso-energetic Stanton number ratios range between 1.0 and 1.4 and show little variation as x/d increases for each value of blowing ratio, however for each x/d, values increases with increasing blowing ratio. The need for greater efficiency in gas turbine engines has resulted in higher turbine inlet temperatures approaching 2000 K. These extreme temperatures, in combination with the high rotational speeds, result in large stress magnitudes on component materials, especially on the blades of the first turbine stage.