In the present work, the chemical composition of syngas is changed by varying the H2/CO ratio, to map the change in the acoustic behavior of a bluff-body combustor. It was observed that with increase in hydrogen concentration in the syngas mixture, the frequency shifts to higher modes and the flame structures changes. The flame oscillations are mapped by means of simultaneous high-speed OH* and CO2* chemiluminescence imaging along with dynamic pressure measurement. The plots of spatial distribution of OH* and CO2* intensity are used to understand change in flame structure with change in chemical composition and also to help in understanding the kinetics affecting acoustic behavior of the flame. The change in flow structures with change in chemical composition of fuel is studied by simultaneous high-speed PIV, OH* chemiluminescence and dynamic pressure measurements. Copyright © 2018 ASME.

Satyanarayanan R. Chakravarthy

Department of Aerospace Engineering

Nikhil Ashokbhai Baraiya

Carbon dioxide

CHEMILUMINESCENCE

Combustors

Pressure measurement

Structure (composition)

Synthesis gas

Turbomachinery

Acoustic behavior

Chemical compositions

CHEMILUMINESCENCE IMAGING

Combustion dynamics

DYNAMIC PRESSURE MEASUREMENTS

Effect of chemicals

FLAME OSCILLATIONS

HYDROGEN CONCENTRATION

combustion

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Effect of Chemical Composition of Syngas on Combustion Dynamics Inside Bluff-Body Type Turbulent Syngas Combustor

Proceedings of the ASME Turbo Expo

An experimental investigation on the effect of syngas composition (H 2 /CO) on thermodynamic instability of a bluff-body combustor is studied. Three syngas compositions, namely, 25%H 2 –75%CO, 50%H 2 –50%CO and 75%H 2 –25%CO, and pure hydrogen and 75%H 2 –25%CH 4 are acoustically characterized by varying the inlet Reynolds number, Re, in the range of 2200–8100. The combustor is observed to undergo two modes of thermo-acoustic instability across the above Re range for all syngas compositions and pure hydrogen, whereas for the H 2 –CH 4 composition, the instability manifests at a single frequency ∼130 Hz. For all the syngas compositions, the pressure oscillations exhibit low frequency (130 Hz) at low Re, and bifurcate to higher frequency (∼500 Hz) at mid-range Re values, while pure hydrogen exhibits bifurcation from the low frequency to the first harmonic (∼260 Hz). The high frequency observed with the syngas compositions is at the third harmonic natural acoustic mode of the combustor and matches thrice the Strouhal frequency of the hydrodynamic oscillations of the shear layer separating from the bluff body. Further investigation into the nature of the dynamic behaviour across the listed fuels is performed using simultaneous time resolved imaging of OH* and CO 2 * chemiluminescence and two-component particle image velocimetry. The peak in the CO 2 * chemiluminescent intensity is found to be axially staggered downstream of that of OH*. This is due to sequential oxidation of H 2 and CO, the former producing OH as an intermediate consumed by the latter. Spatio-temporal analysis of the time-resolved data reveals that the presence of the flame in the shear layer of the bluff-body plays a significant role in modulating the high frequency acoustic excitation. Further, a spatial Rayleigh map is derived based on both the OH* and CO 2 * chemiluminescence, which reveals the bluff-body shear layer dynamics to yield the key driving and damping regions in the present study. © 2019 Hydrogen Energy Publications LLC

International Journal of Hydrogen Energy

Effect of syngas composition on high frequency combustion instability in a non-premixed turbulent combustor

Fuel

A numerical study of the effects of reformer gas composition on the combustion and emission characteristics of a natural gas/diesel RCCI engine enriched with reformer gas

Proceedings of the Combustion Institute

Effects of convection time on the high harmonic combustion instability in a partially premixed combustor

A numerical investigation of structure and NO emissions of turbulent syngas diffusion flame in counter-flow configuration

Energy & Fuels

Effect of H2/CO Composition on Extinction Strain Rates of Counterflow Syngas Flames

The influence of carbon monoxide and hydrogen on the structure and extinction of nonpremixed and premixed methane flames

Effect of chemical composition of syngas on combustion dynamics inside bluff-body type turbulent syngas combustor

Journal	Proceedings of the ASME Turbo Expo
Publisher	American Society of Mechanical Engineers (ASME)
Open Access	No