Application of boundary element method to heat transfer coefficient measurements around a gas turbine blade

Boundary-element method (BEM) with the complete linear element is developed and applied to the steady-state measurements for local heat-transfer coefficients (htc) around a gas turbine blade, especially on actual engine conditions. In the steady-state two-dimensional heat-conduction problem with convective heat-transfer boundary conditions, the solution for the inverse-mixed problem is formulated generally by BEM, where local htc or even fluid temperature may be assigned unknown at any boundary nodal point. Then, the new data-analysis technique for local htc measurements is proposed in which htc on the outside of a hollow blade is computed by BEM from measured blade temperatures on the outer surface, and several measurement simulations are demonstrated to investigate the estimation accuracy. The local htc distribution estimated with about 30 thermocouples has lain within the range of + or - 10 percent compared with the distribution that ought to be.