In order to investigate the cooling system implemented in the passing ways of the gas turbine, it is necessary to simulate the flow through turbine blades using appropriate softwares before starting with experiments. A real numerical simulation always requires complete information from turbine operating conditions, which are generally unknown and expensive to acquire. Therefore, we have to make rational approximations of the operating conditions enabling us to run some numerical simulation and assess the percentage of the variation in the results due to these approximations, so that, we will understand as to how much careful we should move forward with the collection of the information. Numerical results obtained throughendeavour are in good agreement with the experimental results which shows that the conjugate heat transfer is an efficient method for predicting flow pattern and heat transfer through gas turbine vanes. After ensuring the accuracy of the simulation results, the effect of reasonable estimation on boundary conditions used in each boundary has been studied. Results clearly indicate that by changing the turbulence length scale in a reasonable range at the inlet section of the main channel, maximum variation of the predicted temperature does not exceed 0.6%. By changing the turbulence intensity in a reasonable range at the inlet section of the main channel, maximum variation of the predicted temperature is about 1.8%. By making reasonable suggestions for the inlet velocity profile, maximum variation of the predicted temperature reaches about 3.8%. If there is not enough information about the inlet velocity profile it is strongly recommended to use a profile similar to those of experimental data that is used in this study. Using this profile could reduce maximum effects on the predicted temperature to about 2.2%. Results show that the type of curved profiles used for the inlet temperature causes only 0.7% variation on the temperature of the vane.Close review of the results reveals the fact that the results of the curved profiles are in good agreement with industrial observations. Results show that by changing the turbulence intensity in a reasonable range at the inlet of the cooling section, maximum variation of the predicted temperature is less than 1%. By changing the inlet velocity profile of cooling channel between two extreme profiles, maximum variation of the predicted temperature reaches about 2%.Obviously, these conclusions are applicable to a specific vane, and in general they only represent the scale of variation of the numerical results due to boundary conditions variations. Key Words: Gas Turbine, Conjugate heat transfer, Boundary sensitivity, Cooling.
