Experimental Analysis of Confined Jet Flames by Laser Measurement Techniques

Abstract

An experimental analysis of confined premixed turbulent methane/air and hydrogen/air jet flames is presented. A generic lab scale burner for high-velocity preheated jets equipped with an optical combustion chamber was designed and set up. The size and operating conditions were configured to enable flame stabilization by recirculation of hot combustion products. The geometry of the rectangular confinement and an off-center positioning of the jet nozzle were chosen to resemble one burner nozzle of a FLOX®-based combustor. The off-center jet arrangement caused the formation of a pronounced lateral recirculation zone similar to the one in previously investigated FLOX®-combustors [1, 2]. The analysis was accomplished by different laser measurement techniques. Flame structures were visualized by OH* chemiluminescence imaging and planar laser-induced fluorescence of the OH radical. Laser Raman scattering was used to determine concentrations of the major species and the temperature. Velocity fields were measured with particle image velocimetry. Results of measurements in two confined jet flames are shown. The mixing of fresh gas with recirculating combustion products and the stabilization of the methane flame are discussed in detail. The presented findings deliver important information for the understanding of confined jet flames operated with different fuels. The obtained data sets can be used for the validation of numerical simulations as well.

High Momentum Jet Flames at Elevated Pressure: B — Detailed Investigation of Flame Stabilization With Simultaneous PIV and OH-LIF

“…The simplest model combustor is a lab-scale single nozzle burner, that has extensively been investigated at atmospheric conditions, both experimentally [11,12] and numerically [13]. Furthermore, a 3-nozzle model combustor has been investigated at high pressure [8].…”

Atmospheric Experimental Investigations of a Jet-Stabilized SOFC Off-Gas Combustor for a Hybrid Power Plant operated with Biogas

“…The results are a relatively homogeneous temperature distribution, a wide and stable operating range and low emissions [9,10]. Furthermore, the flame flashback risk is reduced due to the high jet velocities, even for fuel with large flame speeds such as hydrogen [11,12]. As summarized by Bücheler et al [3], such jet-flame based FLOX® systems were extended with swirl-stabilized pilot stage burners, in order to further extend the burner operating range [13][14][15].…”

OH planar laser-induced fluorescence measurements with high spatio-temporal resolution for the study of auto-ignition

“…Auto-ignition can contribute to the flame stabilization in combustor systems with high recirculation rates, e.g. swirl [6] or FLOX ® [7,8] combustors, but has to be avoided in mixing sections of premixed combustors or Reheat combustor systems [9][10][11]. For the study of transient processes in complex systems, the (combined) application of time-resolved numerical simulations, such as large eddy simulations (LES), and optical measurement techniques with high spatio-temporal resolution within the same flow geometry is desirable.…”