the test section is balanced with the heat loss via the conductive and convective pathways at the specific wall-to-ambient temperature difference. For each set of heat loss tests, ten heater powers are used to raise the wall temperatures up to 400 K for each test channel. As the heat convection in each test channel is diminished during each heat loss test, the Tw distribution over the heating foil scanned by present IR system is basically uniform. The variation of the external heat loss flux against the mean wall-to-ambient temperature difference exhibits the ascending trend which is well correlated as the function of wall-to-ambient temperature difference for each test channel. These heat-loss correlations are included in the post data processing program to enable the accountancy for local qf distributions. Nevertheless, due to the spatially varied forced convective capabilities in present test channels, the Tw distribution over the ribbed endwall for each heat transfer test is not uniform. Accordingly, the local heat loss flux varies over the heated endwall so that the qf distribution over the heated endwall is not perfectly uniform. The review of entire qf distributions generated by this study reveals that the maximum non-uniformity for qf distribution is about 14%. The streamwise Tb variation is subsequently calculated once the qf distribution over the ribbed endwall is determined. The full-filed endwall Nu distribution at each tested Re for each test channel is defined with the thermal conductivity of coolant evaluated at local Tb.