Conjugate Heat Transfer Analysis of a Rotor Blade With Rib-Roughened Internal Cooling Passages

Abstract

In order to predict temperature distribution of a rotor blade in a gas turbine on a rated condition, numerical analyses of conjugate heat transfer of the internally cooled blade were conducted. The target blade has rib-roughened internal cooling passages. Three-dimensional steady-state numerical analysis was executed with one-dimensional thermo-flow calculation of internal cooling by means of thermal conjugation of inside and outside fields of the blade, which consists of convection heat transfer around the blade, thermal conduction of the blade material and internal cooling. The one-dimensional thermo-flow calculation for the internal cooling was conducted with correlations of friction and heat transfer in rib-roughened channels, and combined with the 3-D analysis of the blade. The present prediction of the temperature profile on the blade coincides with the distinctive features of damage on actual ex-service blades. Moreover, that predicted temperature profile is in agreement with local temperature estimated by using the material of the actual ex-service blades. Influences of distribution of inlet gas temperature and of cooling conditions on the blade temperature were also investigated by using the present numerical procedure.