Measured coolant distributions downstream of single and double rows of film cooling holes

A mass-transfer technique has been used to investigate experimentally the distribution of coolant from two rows of holes with independently varied blowing rates. Both staggered and in-line configurations were investigated for two injection angles and a range of row spacings. Detailed concentration distributions measured at and above the surface are presented and a possible mechanism to account for the large differences in behavior between staggered and in-line configurations is discussed.