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 V Rbased combustor. The off-center jet arrangement caused the formation of a pronounced lateral recirculation zone similar to the one in previously investigated FLOX V R -combustors (Lückerath et al., 2007. "FLOX V R Combustion at High Pressure with Different Fuel Compositions," ASME J. Eng. Gas Turbines Power, 130(1), pp. 011505; Lammel et al., 2010. "FLOX V R Combustion at High Power Density and High Flame Temperatures," ASME J. Eng. Gas Turbines Power, 132(12), p. 121503ff). 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.

Turbulent combustion modelling of a confined premixed jet flame including heat loss effects using tabulated chemistry

“…This section addresses the comparison of the numerical simulations for RANS and LES using the proposed combustion model with the experimental data from Lammel et al [23]. The main flow features can be identified from the instantaneous fields presented in Fig.…”

“…The operating point that is used in the current case is part of a test series of measurements conducted by Lammel et al [23]. The combustor was designed to investigate the flameless oxidation (FLOX R ) regime and its application to gas turbines.…”

“…In the current paper, the proposed combustion model and the implementation in the HPC finite element code Alya is validated for the turbulent premixed jet flame that has been experimentally investigated by Lammel et al [23]. The conditions under investigation correspond to a confined lean premixed methane/air flame with equivalence ratio of 0.71.…”

Advanced Laser-Based Techniques for Gas-Phase Diagnostics in Combustion and Aerospace Engineering

“…26,27 Therefore, OH has been frequently used for tracing the position of the flame front by tracking steep gradients in the OH-planar laser-induced fluorescence (PLIF) image data. [28][29][30] Another approach to track the flame front region is to visualize CH or HCO, which are intermediate combustion species that form and be consumed in this thin layer.…”

Experimental Investigation of the Influence of Combustor Cooling on the Characteristics of a FLOX©-Based Micro Gas Turbine Combustor

“…Lückerath et al [12] compared OH-PLIF and OH*-chemiluminescence images of a jet-stabilised burner for thermal powers up to 475kW at elevated pressure. Major species concentrations, velocity and temperature fields as well as reaction regions were reported by Lammel et al [16] for a generic single nozzle setup using particle image velocimetry, laser raman spectroscopy as well as OH-PLIF measurements.…”