HEAT TRANSFER IN COOLED AERO-DERIVATIVE TURBINE BLADE: A NUMERICAL ANALYSIS

Abstract

Aero-derivative gas turbines have found extensive applications as mechanical drives and in medium-sized utility power plants. It has a higher efficiency due to its high pressure and temperature operations; hence, the need for proper cooling techniques to achieve the required creep life and attain reliability. In this paper, the heat transfer in a cooled aero-derivative gas turbine blade is determined numerically using the Alternating Direction Implicit (ADI) scheme of Computational Fluid Dynamics. The convective heat transfer coefficient of the governing Newton’s law of cooling equation is the basis. A solver was developed for the heat transfer problem based on the selected boundary conditions and designed cooling parameters of the GE PGT25+ aero-derivative gas turbine to obtain the temperature distribution within a cooled blade for 30 minutes in-service operation. There is no significant change in the temperature profiles across the nodal points, varying between 90oC – 600oC. The temperatures within the blade are significantly constant throughout the operating time of the turbine blade, inferring that there was effective heat transfer from the blades to the cooling air since the temperature variation did not exceed the melting point of the blade material. The ADI strategy is, therefore, suitable for heat transfer design computations for complex systems like the gas turbine engine