Design of a Fluidic Actuator with Independent Frequency and Amplitude Modulation for Control of Swirl Flame Dynamics

Abstract

Fluidic actuators are designed to control the oscillatory helical mode, called a precessing vortex core (PVC), which is often observed in gas turbine combustors. The PVC induces large-scale hydrodynamic coherent structures, which can considerably affect flow and flame dynamics. Therefore, appropriate control of this structure can lead to a more stable and efficient combustion process. Currently available flow control systems are designed to control the PVC in laboratory-scale setups. To further develop these systems and find an approach applicable to the industrial scale, a new actuator design based on fluidic oscillators is presented and studied in this paper. This actuator allows for independently adjusting forcing frequency and amplitude, which is necessary to effectively target the dynamics of the PVC. The functionality and flow control of this actuator design are studied based on numerical simulations and experimental measurements. To verify the flow control authority, the actuator is built into a prototype combustor test rig, which allows for investigating the impact of the actuator’s forcing on the PVC at isothermal conditions. The studies conducted in this work prove the desired functionality and flow control authority of the 3D-printed actuator. Accordingly, a two-part stainless steel design is derived for future test conditions with flame.

Editorial for the Special Issue on “Fluidic Oscillators—Devices and Applications”

“…Furthermore, lean combustion devices often involve swirling flames that may be accompanied by a precessing vortex core, which can lead to combustion instabilities and suboptimal emission. In order to prevent this phenomenon, fluidic amplifiers were investigated for volumetric flow modulation of the fuel stream by Adhikari et al [23].…”

Jet Oscillations and Mixing in Fluidic Oscillators: Influence of Geometric Configuration and Scale

“…In the wall-attachment type of FOs, the Coandǎ effect is exploited to generate a self-sustaining oscillation of the jets. This type of FO has generated considerable interest from the process intensification community and has been used for a variety of multiphase processes, such as bubble generation , and liquid–liquid extraction. − FOs are also being reported for antisolvent crystallization of Paracetamol. − Apart from the process applications, FOs also find applications as flow meters, − fluidic actuators, − and flow controllers. ,− In this work, we therefore focus on wall-attachment type FOs.…”