investigation of the flame structures and burning speeds of H₂/CO/air mixtures

• Online Access: http://hdl.handle.net/2047/d20128901

With the potential of synthetic gas to be used as a replacement for natural gas in the gas turbine industry the knowledge of its fundamental thermo-physical properties is of utmost importance. The laminar burning speed and flame structures of spherically expanding flames of hydrogen and carbon monoxide mixtures (Syngas) with air have been studied over a wide range of equivalence ratios, initial mixture temperatures, and initial pressures. The mixtures studied consisted of 0.1:0.9 hydrogen to carbon monoxide ratio at initial temperatures of 298 K and 380 K, and initial pressures of 0.5 atm, 1 atm, and 2 atm. The range of equivalence ratios tested were 0.6, 1, 2, 3, and 5. Based on these initial conditions burning speed was calculated for temperatures ranging from 310-520 K at pressures between 0.5-3 atmospheres. All experimentation was conducted in a constant volume cylindrical vessel fitted in a Schlieren shadowgraph system. The shadowgraph system was used to study the structures of the flames and to understand the transition from smooth flames to cellular flames to illustrate the onset of turbulence. Pressure-time data was obtained during the combustion event through pressure transducers on the combustion chamber wall and were a primary input into the thermodynamic model used to determine the laminar burning speed. The results for the burning speed of H2/CO/Air mixtures at the aforementioned test conditions have been compared with the results obtained by other research groups: the results agree within 7% which is within the margin of error for this experimentation.