The Effect of Periodic Disturbance Patterns on the Efficiency of Active Flow Control in a Linear Stator Cascade

Constant volume combustion (CVC) is a promising way to substantially increase gas turbine efficiency. Shockless explosion combustion and pulsed detonation combustion are potential candidates for CVC integration in gas turbines. Both these schemes operate with sequentially ignited tubes that introduce highly transient flow characteristics in neighboring machine components. One of the most critical parts of turbomachinery is the compressor. In this work, the impact of the firing pattern on the flow field in a compressor stator located upstream is studied. In particular, five combustion patterns are investigated in terms of local blockage and compressor performance. As wake measurements indicate, patterns with low fluctuations of local blockage exhibit less flow deflection, reduced losses, and higher pressure increases compared to those with large fluctuations. Furthermore, the effect of active flow control (AFC) utilizing end-wall blowing is investigated. Experiments show that the impact of AFC varies depending on the pattern, favoring patterns with low fluctuations of local blockage. The results indicate that closed-loop AFC is favorable when a disturbance rejection is of interest but does not significantly improve performance compared to steady blowing.