Conjugate prediction of leading edge film cooling and heat transfer
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Film cooling is commonly applied to the leading edge region of a turbine blade to protect the blade surface from high temperature combustion gases. This paper presents a threedimensional conjugate heat transfer prediction on a cylindrical leading edge model with film cooling. This thermal conjugation consists of internal convection, solid conduction, and external film cooling. The numerical simulation is done using the commercial computational fluid dynamics (CFD) code FLUENT. The realizable k- model with enhanced wall treatment is employed in the simulation. The steady state conjugate solutions are presented for the cylinders made of polycarbonate and stainless steel with low and high thermal conductivity, respectively. The solution of the adiabatic film cooling effectiveness is presented and compared with the Pressure Sensitive Paint (PSP) measurement. The predicted film cooling effectiveness qualitatively agrees with experiment in the trend. However, the CFD over predicts the film cooling effectiveness near the film holes. The conjugate calculations clearly show the leading edge overall cooling performance significantly affected by heat conduction through the cylinder solid wall. The unsteady thermal conjugation simulation is also performed for the polycarbonate cylinder and compared with the Infrared (IR) camera measurement. The unsteady prediction shows higher overall cooling effectiveness along the coolant jet trajectory, however, it under predicts the data between the film cooling hole regions. This implies the present conjugate prediction requires further improvement.