The development and performance of a perforated plate burner to produce vitiated flow with negligible swirl under engine-relevant gas turbine conditions

Abstract

The development and performance of a perforated plate burner (PPB) operating using premixed natural gas and air at engine-relevant inlet temperatures and combustor pressures with thermal powers up to 1 MW is discussed. A significant benefit of using burners with simplified flow fields, such as the PPB, for experimental studies in the laboratory is the potential for decoupling the complex fluid dynamics in typical combustors from the chemical kinetics. The primary motivation for developing this burner was to use it as a source of vitiated flow with negligible swirl for reacting jet in vitiated crossflow experiments. The design methodology for the PPB is described, including plate geometry selection and flashback mitigation features. The stable operation of the PPB within a high-pressure test rig was validated: successful ignition, effective use of red-lines for flashback mitigation, and long duration steady-state operation in both piloted and nonpiloted modes were all observed. Exhaust gas emissions measured using a Fourier-transform infrared (FTIR) spectrometer showed very good performance of the PPB in terms of the combustion efficiency (based on measured CO and UHC), and a stability diagram of the PPB was developed as a function of the equivalence ratio and the PPB hole velocity. FTIR measurements also showed very low levels of NOX in nonpiloted operation that were generally within 3 ppm (reported dry and referenced to 15% O2). The capability for steady-state operation, high combustion efficiency, and low levels of NOX makes this PPB an excellent burner candidate for combustion experiments in the laboratory.

An optically accessible secondary combustion zone for the transverse injection of reacting jets into a high-speed, vitiated crossflow within a staged, gas turbine model combustor

“…The headend assembly primarily consists of a perforated plate burner (PPB) operated with premixed natural gas and air and with a hydrogen pilot flame. Details of the PPB have been covered previously [45]. The PPB was used to create a hot vitiated flow with negligible swirl, which was then accelerated by the contraction section (1:41 exit-toinlet area ratio) as the flow geometry was transitioned from circular to rectangular.…”

“…The current rig iteration features a flow transition piece, described further in the next section, between the exit of the flow contraction section and the optically accessible SCZ. The same NO X quench and sample stage that was previously used is located directly after the axial combustor to enable accurate control of the residence time by freezing the thermal NO X production in the flow [44,45]. This was achieved by radially injecting water into the combustion gas flow to reduce the gas temperature below 1300 K and a length of pipe was used to promote mixing before exhaust gases were sampled using a water-cooled probe.…”

“…The exhaust gas sample was transported to the emissions measurement system using a heated line at 464 K to prevent condensation. Emissions were characterized using a Fourier transform infrared (FTIR) spectrometer from MKS Instruments operating at 1 Hz and in a manner identical to our previous work [44,45]. The experiment was remotely controlled using a National Instruments LabVIEW Virtual Instrument (VI) with temperature and pressure instrumentation for rig condition monitoring.…”

“…• Rectangular flow path that can easily interface with the existing flow contraction section [44,45]. • A modular axial injection design to facilitate incorporation of injectors with different jet diameters, which would be flush with the combustor wall or elevated into the crossflow.…”

Numerical Study of a Flow Through a Grid Placed in a Bunsen Burner

“…Kalt et al [9] were able to vary the turbulence intensity with only varying the position of a perforated grid placed upstream of the burner exit. Some recent works in the same research field have also been reported [10,11]. However, this type of grid poses a serious problem when high turbulence intensity combined with good homogeneity and isotropy is needed.…”