Investigation into wind effects on fire spread on inclined wooden rods by multi-spectrum and schlieren imaging

A combined imaging system that can monitor the visible flame, invisible hot flow, flame temperature and surface temperature was developed to investigate the combustion of wooden rods inclined at 30° under forced air flow. A micro wind tunnel is designed to generate the forced air flow that is at an angle with the fire rod. It is found that a low-speed air flow can enhance the combustion of the burning lifetime and charring rate, while a high wind speed can decrease the intensity of combustion. There were three aspects that were found to influence the burning and spreading of the fire: 1. The effect of flame temperature; 2. The temperature change of the wooden surface; 3. The effect of the flow field around the burning rods, particularly for the flow field underneath the rod surface. The statistics and visualisation have enhanced the understanding of the mechanisms of wood combustion in a forced air flow. The developed imaging system is beneficial for monitoring the combustion process because it can monitor the flame temperature, wood surface temperature and visualise the invisible hot combustion products simultaneously.