Heat Flux from Turbulent Premixed Flame to the Wall of a Constant Volume Vessel

Instantaneous heat flux to the wall of a combustion chamber was measured by a co-axial thermocouple with a thin fin junction for the case with laminar and turbulent flame of a propane-air mixture. The experiment was performed in a constant volume vessel of the disk-type with swirl flow. When the laminar flame arrived at the wall, the heat flux had one sharp peak. In the case of the turbulent flame, however, the heat flux with multiple sharp peaks was observed. It is considered that this phenomenon corresponds to the structure of the turbulent flame. The maximum value of peak heat flux, q_max is approximately proportional to {k(T_i-T_u)/δL}^0.61, where (T_i-T_u)/δL is a characteristic value of the temperature gradient in a preheat zone of laminar flame and k is the heat conductivity. The same relation is obtained, even when the flow velocity, equivalence ratio or measuring position are varied.