In this dissertation results from a compressor cascade with periodic non-steady outflow conditions are shown. All experimental results were conducted utilizing a 2D low-speed compressor cascade at a Reynolds number of Re=600,000. The presented research gained important insights on the flow structures as they occur in a gas turbine with pulsed detonation combustion (PDC). In such a scenario the outflow condition in the last stator vanes is highly unsteady and periodically occurring aerodynamic overloads of the airfoils can lead to a compressor stall. The outflow-boundary condition was mimicked using 21 flaps that were mounted in the wake of a compressor cascade. These flaps were used to locally block the outflow of a stator passage. This simulated the condition of a closed combustion tube in a PDC-cycle. The flaps were opened/closed sequentially with a given reduced frequency. The resulting flow dynamics led to strong periodic flow separations in the stator passages. Pulsed blowing active flow control (AFC) was applied to re-attach the flow. The designed actuators were based on the principle of fluidic amplification. Side-wall actuators were used to mitigate the corner separation of the low aspect ratio, highly loaded stator blades. Another set of actuators was installed at the suction surface of the compressor blades. These blade actuators mitigated the flow separation on the suction surface of the stator blades. With the combined AFC setup it was feasible to fully suppress flow separations. This led to a loss reduction of Δζ=12% and simultaneously increased the static pressure recovery by ΔC_p=7%, using optimized actuation momentums for side-wall and blade actuators.
Active flow control on a highly loaded compressor cascade with periodic nonsteady outflow conditions
Aktive Strömungskontrolle an einem hochbelasteten Verdichtergitter mit instationären Randbedingungen
2021
Sonstige
Elektronische Ressource
Englisch
compressor aerodynamics , aktive Strömungskontrolle , instationäre Strömungen , Pulsstrahltriebwerk , separated flow , active flow control , compressor stator , fluidische Aktuatoren , Verdichter-Stator , fluidic actuator , pulsed detonation gas turbine , Verdichteraerodynamik , unsteady flow , abgelöste Strömung
DDC: | 629 |
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