Effects of rotation on impingement cooling of turbine blades

The effects of rotation on impingement cooling of turbine blades were studied experimentally as a specialized facility at M.I.T. A foil heated resistively was cooled by a jet flow on one side and temperature monitored on the other. Rotating the blade limits the heat transfer path to conduction through the support structure and radiation. IR radiometry furnishes the temperature distributions on the chamber wall, permitting the internal heat transfer coefficient to be measured. The heat transfer efficiency has been found to fall as much as 30 percent as rotational speed increases. The conditions observed confirm the significance of rotational effects, particularly with regard to potential early blade failure.