An infrared thermography imaging system for convective heat transfer measurements in complex flows

An infrared thermography imaging system is described for spatially resolved convective heat transfer measurements when used in conjunction with thermo couples, energy balances, digital image processing, zinc-selenide windows, and unique in situ calibration procedures. The usefulness of the system and the techniques developed are demonstrated by measurements made in two diff erent environments with complete, three-dimensional flow features. First, s patial variations of surface Nusselt numbers are measured along the concave surfaces of a swirl chamber whose geometry models an internal passage used to cool the leading edge of a turbine blade. Second, spatially resolved di stributions of the adiabatic film-cooling effectiveness are measured downst ream of film-cooling holes on a symmetric turbine blade in transonic flow.