Effect of Syngas Fuel Compositions on the Occurrence of Instability of Laminar Diffusion Flame
Abstract
The paper presents a numerical investigation of the critical roles played by the chemical compositions of syngas on laminar diffusion flame instabilities. Three different flame phenomena – stable, flickering and tip-cutting – are formulated by varying the syngas fuel rate from 0.2 to 1.4 SLPM. Following the satisfactory validation of numerical results with Darabkhani et al. [1], the study explored the consequence of each species (H2, CO, CH4, CO2, N2) in the syngas composition. It is found that low H2:CO has a higher level of instability, which however does not rise any further when the ratio is less than 1. Interestingly, CO encourages the heat generation with less fluctuation while H2 plays another significant role in the increase of flame temperature and its fluctuation. Diluting CH4 into syngas further increases the instability level as well as the fluctuation of heat generation significantly. However, an opposite effect is found from the same action with either CO2 or N2. Finally, considering the heat generation and flame stability, the highest performance is obtained from 25%H2+75%CO (81 W), followed by EQ+20%CO2, and EQ+20%N2 (78 W).