Flame structure and radiation characteristics of CO/H2/CO2/air turbulent premixed flames at high pressure

High-pressure hydrogen/carbon monoxide syngas turbulent burning velocities measured at constant turbulent Reynolds numbers

“…As to the important turbulent Reynolds number (Re T h u 0 L I /n), it has long been recognized as an intensity indicator of turbulence and an influential factor of turbulence effect on flames, where u 0 and L I are the root-mean-square (RMS) turbulent fluctuation velocity and the integral length scale of turbulence and n is the kinematic viscosity of reactants. Unfortunately, recent syngas turbulent combustion studies [4,5] merely looked at the promotion effect of increasing pressure ( p) on turbulent burning velocities (S T ) of syngas fuel due to the interaction between turbulent straining and enhanced flame instabilities at elevated pressure without any consideration on the impact of Re T enhancement. The increase of Re T is due to the decrease of n as p increases, because n w r À1 w p À1 , where r is the fluid density.…”

“…The facility can be used to generate the wanted high-Re T near-isotropic turbulence [5,6], as to be discussed later. Typical syngas fuels can be simply decomposed into two major compositions, H 2 and CO, plus a third composition including the rest of other compositions such as CH 4 , CO 2 , and N 2 [1,5]. There are three commonly-used syngas gasifiers: The moving-bed gasifier, the fluidized-bed gasifier, and the entrained-flow gasifier.…”

“…[7e11]], of which the relevant reduced oxidation mechanism has also been established [11]. On the other hand, turbulent flame properties of CO and H 2 syngas under elevated pressures are not yet understood, although a few yet valuable experimental measurements, such as for stabilized Bunsen-type turbulent syngas flames at elevated pressure [4,12] and for high-pressure centrally-ignited expanding turbulent syngas flames [5], can still be found. Contrary to the decreasing trend of S L at elevated pressure [8,11,13], turbulent flame speed or S T has been found to increase with increasing pressure at constant u 0 [6,14e16].…”

The effects of unburned-gas temperature on the characteristics of cellular premixed flames generated by hydrodynamic and diffusive-thermal instabilities in large space: fractal dimension of cellular-flame fronts

“…The numerical results on intrinsic instability will be important information for the industrial application of premixed flames, e.g. premixed-type gas turbines, where combustion phenomena are strongly affected by intrinsic instability (Kobayashi et al, 2007;Ichikawa et al, 2011). Thus, we have to treat reactive flow in large space to obtain the useful knowledge on industrial applications.…”

Laminar burning velocities and flame characteristics of CO–H2–CO2–O2 mixtures

“…This substantial fuel variability has great influence on fuel property and combustion process and is a big challenge for combustor design. Many researches on fundamental combustion characteristics of syngas have been conducted, such as the measurement of laminar burning velocity [7,10,11] and ignition delays [12,13], the measurement of turbulent burning velocity at gas turbine relevant conditions [14,15], the development of detailed and optimized chemical reaction mechanism [17e19]. But all of these previous studies were concentrated on the syngaseair mixtures, while few researches were reported on syngas oxyfuel combustion.…”