Thermoacoustic Instability Suppression and Heat-Release Forcing of a Laminar Flame Using Ionic Wind

TL;DR

This paper introduces a novel electrically controlled actuator using ionic wind to stabilize laminar flames and suppress thermoacoustic instabilities efficiently, with low power consumption and no moving parts.

Contribution

A new actuator concept utilizing sub-breakdown electric fields and plasma effects for flame stabilization and heat-release forcing is proposed and demonstrated.

Findings

Reduced thermoacoustic sound pressure level by 27 dB

Achieved stabilization with only 40 mW power

Suppressed instability in less than 60 ms

Abstract

Advancements in combustion technologies are often impeded by complex combustion dynamics. Active control has proven effective at mitigating these dynamics in the lab, but mass adoption requires more affordable, lightweight, and reliable actuators. Here, a new actuator concept is presented which utilizes sub-breakdown electric fields, the inherent plasma nature of flames, and the electrohydrodynamic effect to create flame stabilization points. These electrically controlled stabilization points allow variable distortion of a laminar flame and bidirectional forcing of the flame heat release. The electric field-based actuator is combined with a simple feedback controller to demonstrate suppression of a thermoacoustic instability. The instability sound pressure level was reduced by 27 dB and in less than 60 ms upon enabling the controller. The use of a sub breakdown electric field requires a mere 40 mW to stabilize a 3.4 kW thermal power flame. The absence of any moving parts and low electrical power required make this a promising actuator concept for many combustion applications.