Microturbine Blade Cooling

The main technical barrier to commercial use of microturbines is its low efficiency, not exceeding 15%. Efficiency and specific power are as high as the Turbine Inlet Temperature (TIT), generally limited to 950°C in microturbines, as its tiny rotors make internal blade cooling impossible. This work uses Computational Fluid Dynamics (CFD) to develop an external cooling system of the blades of a microturbine by incorporating a compressor into the disk to blow air over the blades’ walls. The engine used as the basis of the work is the FD-3/64. The work was divided into two steps. In the first, Step 1, the reactive flow in the combustor was simulated to obtain the boundary conditions for Step 2. In Step 2, the flow through the turbine wheel during rotation is simulated. Four rotor models were simulated. Two models significantly reduced the mean blade temperature, the first at 215 K at the expense of 2.5 times the cold airflow than the second model, which in turn achieved a 168 K reduction with only 5.22% of the main airflow. From the FD-3/64 design, a complete engine was built to be used for further testing of the best cooling system developed in this project.