Abstract The wake characteristics of bluff-body-stabilized flames are a strong function the density ratio across flame and relative offset between shear layer. This paper describes systematic experimental measurements stability calculations dependence flow field sheet dynamics upon ratio, ${\rho }_{u} / {\rho }_{b} $ , over Reynolds number range 1000–3300. We show that two fundamentally different flame/flow behaviours observed at high low values: stable, noise-driven fixed point limit-cycle...

Abstract A confluence of technology development, policy support, and industry investment trends is accelerating the pace Hydrogen (H2) demonstrations, increasing likelihood power sector impacts. In preparation for a large scale shift toward decarbonization low carbon future, several major equipment manufacturers are developing gas turbines that can operate on high H2 volume fuel. Many have capable systems now range from 5% to 100% H2. Units with capabilities either using diffusion burner or...

Hydrogen (H2) fuel is a promising means for long duration energy storage and dispatchable utilization of intermittent renewable power, which can be combusted without CO2 emissions. Several recent studies have noted that hydrogen blended systems elevated NOx emissions relative to natural gas, prompting significant concerns about the air quality impacts economy. However, many these results are nonpremixed it not entirely clear what being held constant comparisons (temperature, etc.). Given...

Turbulent flames in practical devices are subject to a superposition of broadband turbulence and narrowband harmonic flow oscillations. In such cases, have space–time correlated wrinkles, superposed with turbulent disturbances that interact nonlinearly. This paper extends our prior experimental work characterise quantify these flame dynamics. We extract ensemble-averaged edge velocity by ensemble-averaging the instantaneous data at same phase respect forcing cycle. shows spatio-temporal...

High-speed synchronized stereo particle-imaging velocimetry and OH planar laser-induced fluorescence (PIV/OH-PLIF) measurements are performed on multiple $R{-}\unicode[STIX]{x1D703}$ planes downstream of a high-Reynolds-number swirling jet. Dynamic-mode decomposition (DMD) – frequency-resolved data-reduction technique is used to identify characterize recurrent flow structures. Illustrative results presented in field for two cases the nominal dynamics where self-excited combustion driven...

Abstract Hydrogen (H2) fuel for gas turbines is a promising approach long duration storage and dispatchable utilization of intermittent renewable power. A major global discussion point, however, the potential air quality impact hydrogen combustion associated with nitrogen oxide (NOX) emissions. Indeed, several studies in literature have reported elevated NOX concentrations terms dry ppmv at 15% oxygen (O2) as fuel's H2 fraction increased. Yet, emphasized this work, practice directly...

This paper describes linear and nonlinear interactions between forced axial acoustic oscillations the global mode of reacting wake. work is motivated by problem combustion instabilities, where associated with natural combustor modes excite hydrodynamic instabilities flow that, in turn, induce heat release oscillations. Wake flows density stratification can be globally stable or unstable at high Reynolds numbers, so change across flame has significant influence on dynamics. Measurements were...

This paper describes results from an experimental study on influences of liquid fuel properties lean blowout (LBO) limits in aero-type combustor. In particular, this work aimed to elucidate the roles chemical and physical LBO. Fuel stem structure, thus governing kinetic behaviors oxidation characteristics (e.g., ignition or extinction time scales) others thermal stability sooting tendencies). affect spray atomization evaporation rates). Eighteen different fuels, with a wide range properties,...

The flame or flow behavior of a turbulent reacting wake is known to be fundamentally different at high and low values density ratio $({\ensuremath{\rho}}_{u}/{\ensuremath{\rho}}_{b})$, as the transitions from globally stable unstable. This paper analyzes nonlinear dynamics present in bluff-body stabilized flame, identifies transition characteristics ${\ensuremath{\rho}}_{u}/{\ensuremath{\rho}}_{b}$ varied over Reynolds number (based on lip velocity) range 1000--3300. Recurrence...

This paper presents bifurcation analyses characterising the nonlinear dynamics of fully developed laminar annular jets with respect to centrebody diameter ${ {d}}$ , Reynolds number {Re}}$ and swirl ratio {S}}$ . Similar flows appear in numerous applications feature a vibrant range topological dynamical characteristics associated phenomena including shear layer separation vortex breakdown. Our results begin by describing non-monotonic evolution axisymmetric jet's steady topology under...

This paper describes an experimental investigation of a transversely forced, swirl stabilized combustor. Its objective is to compare the unsteady flow structures in single and triple nozzle combustors determine how well configuration emulates characteristics multinozzle one. The experiment consists series velocity field measurements captured on planes normal jet axis. As expected, there are differences between fields, but not large regions upstream merging zone. Direct comparisons...

This paper explores the hydrodynamic stability of bluff body wakes with non-uniform mean density, asymmetric and velocity profiles. work is motivated by experiments [S. Tuttle et al., “Lean blow off behavior asymmetrically-fueled body-stabilized flames,” Combust. Flame 160, 1677 (2013)], which investigated reacting equivalence ratio stratification and, hence, asymmetry in base flow density They showed that highly stratified cases exhibited strong, narrowband oscillations, suggestive global...

This paper presents an experimental and theoretical investigation of high-Reynolds-number low-density reacting wakes near a hydrodynamic Hopf bifurcation. configuration is applicable to the wake flows that are commonly used stabilize flames in high-velocity flows. First, study conducted measure limit-cycle oscillation this bluff-body wake. The experiment repeated while independently varying lip velocity density ratio across flame. In all cases, exhibits sinuous oscillation. Linear stability...