Radiative Effectiveness on the Aero- and Thermodynamics in a Highly Thermally Loaded Film Cooling System

With the increasing of the gas turbine inlet temperature, the radiative heat transfer plays a more important role in the total heat transfer. In this paper, a high temperature test rig has been built to research the radiative effect in high temperature film cooling. The test section is made up of a high temperature hot gas channel and a middle temperature coolant air channel which are separated by a flat plate with a row of film cooling holes. The goal is to analyze the effects of radiation and its interaction between conduction and convection in the internal and film cooling which consider the heat transfer in both gas and solid. Meanwhile, the numerical study on the test cases are also carried out by combining conjugate heat transfer with radiative models. The fluid and solid regions were solved simultaneously. The Discrete Ordinates (DO) model and the Weighted Sum of Gray Gases Model (WSGGM) has been used to solve the radiative transfer equation for the radiation modeling. The results show that the temperature of the plate increase greatly when the radiation is taken into account and the temperature gradient through the plate becomes much larger. The temperature distribution has been changed and become smoother in spanwise direction. The results also indicate that the internal emissivity of the inlet has an influence mainly on the whole temperature of the plate, which suggests that the control of inlet emissivity is a good way for prevent over-high temperature on the first stage gas turbine vane.