Measurements of Laminar Flame Speeds of Alternative Gaseous Fuel Mixtures

Laminar burning velocities and Markstein lengths were obtained at various ratios of hydrogen (volume fraction from 0 to 100%) enriched to natural gas, and equivalence ratios (O from 0.2 to 1.7). The effect of stretch rate on flame was also analyzed. It was found that the laminar burning velocity is increased nonlinearly with the increase of hydrogen fraction for lean equivalence ratios. For stoichiometric equivalence ratio there is a linear relationship between flame radius and time, while for rich mixtures there is approximate linear relationship. The Markstein length decreases and flame instability increases with the increase of hydrogen enrichment in mixture. For a fixed hydrogen fraction, the Markstein number shows an increase and flame stability increases with the increase of equivalence ratios. The laminar flame speed results were compared with other researches and it was found a good agreement.

The measurement of laminar burning velocities and markstein numbers for hydrogen enriched natural gas

n the present work, experiments are conducted on a newly designed flame propagation testunit using burners of different geometries (L/D ratio) at different air-fuel ratios to calculate theflame speed. From the experimental data obtained, design plots are drawn to study the flamestability zone under different conditions.  Using the above test results and standard mathematicalcurve fitting techniques for a function of two variables, an equation has been derived which canbe utilised by the designers to design an optimum burner for premixed flames which providesstable flame with maximum flame speed for the best burner geometry.

http://publications.drdo.gov.in/ojs/index.php/dsj/article/download/1799/890

G.C. Pant

Papers

Experimental Investigation and Mathematical Modelling to Study thePremixed Laminar Flame Propagation