Properties of premixed hydrogen/propane/air flame in ceramic granular beds

This study investigated how various H₂ concentrations of fuel mixed with a ceramic granular bed (CGB) affect the propagation characteristics of a premixed C₃H₈/air flame. The results showed that at low firing rates (Γ < 1.5 kJ/s), as Γ increased, adding H₂ exerted little effect on the flame temperature and absolute flame front velocity (S_ab); however, at high Γ (Γ > 1.5 kJ/s), as Γ increased, adding H₂ caused a significant decrease in the flame temperature and a substantial increase in S_ab. Thus, heat transfer was not obvious, and the flame reaction zone was relatively broad. Although adding H₂ moved the flame reaction zone upstream, the heat transfer mechanism reduced the effect that resulted from adding H₂ under low Γ conditions. Because of the characteristics of H₂, the flame reaction zones moved upstream, causing the flame thickness and heat loss to increase. Adding H₂ decreased the flame temperature and increased S_ab.