Numerical Analysis of a Flow Control System for High-Pressure Turbine Vanes Subject to Highly Oscillating Inflow Conditions

Under the prism of introducing pioneering technologies in the propulsive field, the Rotating Detonation Engine (RDE) continuously attracts the Gas Turbine (GT) research community. However, how to effectively couple an RDE with High Pressure Turbine (HPT) stages is still debated. In fact, time dependent flow conditions from the RDE greatly affect turbine performance, thus reducing the positive impact of Pressure Gain Combustion (PGC) on the overall cycle efficiency. The present numerical work aims at analysing both the impact of a pulsating inflow on the performance of a newly designed high pressure turbine vane and the effectiveness of a flow control system in governing the oscillations within the vane passage. First, a baseline vane capable to ingest high enthalpy flow at an inlet Mach number of 0.6 is introduced. A total number of 297 samples are generated by varying the 18 geometrical parameters that characterize the vane endwalls and airfoil profile with the help of Latin Hypercube sampling method. Then, an optimization strategy is performed using steady inflow conditions allows for minimizing vane loss coefficient, thus providing the final geometry of the new vane. In the second part of the work, a flow control system is proposed by placing a series of holes in the endwalls of the vane. Air at constant stagnation conditions is injected upstream of vane leading edge. Unsteady calculations with and without flow control, including similar pulsating conditions from the RDE provide an insight to the generation and evolution of the secondary flow structures inside of the passage. The main outcome of this analysis is that the flow control system intensifies the passage vortices providing less oscillating flow at the vane exit section, which is beneficial for the aerodynamic performance of a subsequent blade row.