Heat transfer distributions on a cylinder with simulated thermal barrier coating spallation

Detailed heat transfer distributions are presented over a turbine blade lea ding-edge model with simulated thermal barrier coating spallation, The blad e leading-edge region is simulated by a cylinder in a crossflow with a tail board. The heat transfer measurements are presented only on one side of the front half of the cylinder. The simulated spallation cavities are rectangu lar in shape and have rounded corners. The effect of a spallation cavity is studied at four different locations (0-20, 10-30, 20-40, and 35-55 deg). T wo different cavity depths are studied at each location to understand the e ffect of spallation depth on local heat transfer distributions. The effect of freestream turbulence on detailed heat transfer is also presented for ea ch case, Detailed heat transfer measurements are obtained using a transient liquid crystal technique. Detailed heat transfer distributions present the local high-heat transfer and low-heat transfer regions inside and outside the spallation. Results show that spallations can enhance heat transfer up to two times compared with that for a smooth surface. Results also show tha t the spallation location and depth have a strong effect on local heat tran sfer distributions on the leading edge. An increase in freestream turbulenc e further increases the heat transfer coefficients caused by the spallation .