Modelling of the Temperature Distribution in a Cooled Aeroderivative Gas Turbine Blade with Cooling Holes

Abstract

Aero-derivative gas turbines have found extensive applications, as mechanical drives and medium sized utility power plants on offshore platforms and in petrochemical industries; because of its high operating temperature and pressure, it has a higher efficiency. The high operating conditions of the engine makes it necessary to adopt effective cooling techniques to achieve the required creep life and attain reliability. This makes the study of the heat transfer within the gas turbine blade essential. This study models the temperature distribution in a cooled aero-derivative gas turbine blade. A numerical model was developed from the interpolation of the Newton’s law of cooling equation and the Alternating Direction Implicit (ADI) scheme. A MATLAB solver was generated for the heat transfer problem based on the selected boundary conditions and designed cooling parameters of model engine: GE PGT25+ aero-derivative gas turbine. It was found that there was effective heat transfer from the blades to the cooling air with a cooling effectiveness of 0.5, and the temperature gradient within the blade was within safe operating limits not exceeding the melting point of the blade material. It was deduced that the ADI strategy accurately compute temperature distributions within the blade, in time and space, thereby making it suitable for heat transfer design computations for complex thermodynamic systems like the gas turbine engine.