Heat transfer, adiabatic effectiveness and injectant distributions downstream of single rows and two staggered rows of film-cooling holes with simple and compound angles

Abstract

Experimental results for two compound angle injection systems (configuration 1 and 3), and for a single injection system (configuration 2) are compared in this thesis. The effects of blowing ratio, spanwise hole spacing, hole angle orientation, and streamwise position (x/d) are discussed in reference to measurements of spanwise-averaged adiabatic effectiveness, iso-energetic Stanton number and Stanton number for 0 approximately equal to 1.5 obtained downstream of both one row of holes and two staggered rows of holes. Results indicate that effectiveness depends mostly on four parameters: simple or compound angle injection, spanwise hole spacing, one or two rows of holes, and blowing ratio. Results show that for a specified blowing ratio, for all configurations tested to date, spanwise-averaged adiabatic effectiveness is greatest at lower x/d values but decreases with streamwise development as the injectant is convected downstream. The rate of spanwise-averaged adiabatic effectiveness decrease is dependent on the blowing ratio, and mostly a result of lift-off of the injectant from the test surface at x/d values less than about 20. At larger x/d, spanwise-averaged adiabatic effectiveness values generally increase with blowing ratio mostly because of grater amounts of injectant along the test surface,. Results also show that the iso-energetic Stanton number ratio lies between 1 and 1.35 for all cases studied and generally increases with blowing ratio for a given x/d.