Heat Transfer to the Wall of End Gas Side during Propagation of Premixed Flame in a Closed Vessel : Heat Flux Measurements by Both Interference Image Analysis and Thin Surface Thermocouple Methods

Abstract

It is necessary to know the heat flux near a wall in order to understand the unsteady heat transfer in a combustion chamber. In this study, a fuel-air mixture was ignited at the center of a constant-volume vessel and the heat flux was determined from the change in the temperature distribution in the boundary layer near the wall of the end gas side by analyzing the interference image. The heat flux was compared with that from a thin surface coaxial thermocouple with high response. It was found that before the flame arrives at the wall, the heat transfer is smaller than the thermal radiation from the flame, and the temperature of unburned gas changes nearly adiabatically. After the flame reaches the wall, the heat flux due to the temperature gradient becomes larger than that due to the thermal radiation.