An experimental study has been conducted to explore the behavior of the radiative ignition of polymethylmetacrylate(PMMA) in a confined enclosure by examining the ignition delay, the ignition surface temperature, the ignition location and the ignition process by changing various hot wall temperature. In addition, the effects of solid fuel and hot wall orientation on the ignition delay and the ignition surface temperature were studied.
Ignition delay time is founded to be shorter when the hot wall is located at the bottom. Ignition surface temperature becames lowest for the hot top wall case. These are due to buoyancy effect. In most cases the ignition points are observed to be located in the upper region of the hot wall with the hot vertical wall, whereas it is center region of the hot wall with the hot bottom wall. Since this ignition mechanism of solid fuel is the gas phase reaction and the radiative heat flux of hot wall is rather lower, the ignition is considered to be controlled by the mixing process. Therefore, the ignition ,where appropriate mixture of fuel and oxygen exists, occurs near the hot wall. The video recording of burning process with the hot vertical wall shows that the flame propagates along the hot wall where there is sufficient oxygen exists.