A modified extremum-seeking closed-loop control system is proposed for jet mixing enhancement. The system introduces a variable perturbation component that may act to adjust adaptively the searching range of the optimal control signal. The actuator is a single pulsed minijet injected radially into the main jet before its issue. The excitation frequency for the minjet is controlled by an electromagnetic valve. The open-loop control measurements indicate that, given the duty cycle and the mass flow rate ratio of the minijet to the main jet, the decay rate of jet centerline mean velocity, which provides a measure for jet mixing, displays a maximum at the optimum frequency ratio , where is the preferred-mode frequency of the main jet. Comparison is made between the modified and classical systems. Although both may find automatically the optimal and hence a maximum , the modified system achieves a contraction in the fluctuating , when the control target is reached, by 70%, and subsequently an increase in by 12%. The new system further exhibits a better robustness than the classical.
Modified Extremum-Seeking Closed-Loop System for Jet Mixing Enhancement
AIAA Journal ; 55 , 11 ; 3891-3902
2017-07-06
12 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Modified Extremum-Seeking Closed-Loop System for Jet Mixing Enhancement
Online Contents | 2017
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