Influence of flame-holder temperature on the acoustic flame transfer functions of a laminar flame

Abstract

OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. a b s t r a c tThe occurrence of combustion instabilities in high-performance engines such as gas turbines is often affected by the thermal state of the engine. For example, strong bursts of pressure fluctuations may occur at cold start for operating conditions that are stable once the engine reaches thermal equilibrium. This observation raises the question of the influence of material temperature on the response of flames to acoustic perturbations. In this study, we assess the influence of the temperature of the flame holder for a laminar flame. Both experiments and numerical simulations show that the Flame Transfer Function (FTF) is strongly affected by the flame-holder temperature. The key factors driving the evolution of the FTF are the flame-root location as well as the modification of the flow, which affects its stability. In the case of the cooled flame-holder, the formation of a recirculation zone is identified as the main impact on the FTF.

Fluctuation and extinction of laminar diffusion flame induced by external acoustic wave and source

“…Since the stability of the laminar flame is susceptible to the temperature of the burner 26 , the flame would first burn for 5 min before each experiment to ensure a stable temperature on the burner nozzle, monitored by a thermocouple. For each test, a sound field with specific frequency and pressure was first generated, and there was a soundproofing panel to separate the flame from the sound field.…”

Impact of symmetry breaking on the Flame Transfer Function of a laminar premixed flame

“…lndeed, one can show from first principles [17,18] that the flame response is driven by its length and the dynamics of its root. While the length greatly impacts the delay, the dynamics of the flame root drives the gain of the FTF [4,6]. Moreover, the rotation of the cylinder breaks the symmetry of the flow so that the bulk velocities on both sides of the flame holder are different.…”

“…Using larninar Direct Numerical Simu lations (ONS) validated by experiments, Brebion et al [3] investigated the influence of the cylin drical flame holder's temperature on the flame an choring mechanism. ln their follow up study, Mejia et al [4] investigated the influence of the cylin der's temperature on the Flame Transfer Function (FTF). The effect of rotation of the cylinder on the fl ame anchoring mechanism was explained by Xavier et al [5] and Mejia et al [6].…”

Mitigating self-excited flame pulsating and thermoacoustic oscillations using perforated liners

“…This is due to the fact that acoustic pressure suppressed the intrinsic hydrodynamic instability arising from thermal expansion. Mejia et al [14] experimentally and numerically assessed the effect of flame-holder temperature on the flame transfer function (FTF) of a laminar flame. The formation of a recirculation zone is found to affect strongly on the FTF, when a cooled flame-holder is considered.…”