Effect of hydrogen addition on the laminar flame speed of biogas. Experimental and numerical study

In this study, the laminar flame speed of biogas/H. fuel mixtures is measured from pure biogas to biogas with an addition of 15% H. in volume by using the method of the inner cone of combustion zone. The laminar flame speed is measured by mean of the geometric parameters of combustion cone capturing images of the flames. The aeration factors covers from stoichiometric conditions to lean conditions. Experimental results have been compared with numerical results obtained with CHEMKIN software, using GRIMECH kinetical mechanism, with good agreement between them and with previous works, showing the reliability of the method used. The trends on laminar flame speed experimental results obtained are explained by mean of numerical results on temperature profile and heat release rate. Hydrogen addition in biogas flames show an important effect, especially in zones near stoichiometric flames, decreasing its effects in lean mixtures combustion.