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

•Adding H2 moved the flame reaction zone upstream.•Adding H2 caused the flame thickness and heat loss to increase.•Adding H2 decreases flame temperature and increases absolute propagation velocity.

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 (Sab); 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 Sab. 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 Sab.

Graphical abstractThis paper discusses how various H2 concentrations of fuel mixed with a ceramic granular bed (CGB) affect the transfer characteristics of a premixed C3H8/air flame. The results showed that at low Γ (Γ < 1.5 kJ/s), as Γ increased, adding H2 exerted little effect on the flame temperature and absolute flame front velocity (Sab); 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 Sab. Heat transfer was thus 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 of 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 Sab.Figure optionsDownload full-size imageDownload as PowerPoint slide