Abstract:

Cleaning up residual fires is an important part of forest fire management to avoid the loss of forest resources caused by the recurrence of a residual fire. Existing residual fire detection equipment is mainly infrared temperature detection and smoke identification. Due to the isolation of ground, temperature and smoke characteristics of medium and large smoldering charcoal in some forest soils are not obvious, making it difficult to identify by detection equipment. CO gas is an important detection index for indoor smoldering fire detection, and an important identification feature of hidden smoldering ground fires. However, there is no research on locating smoldering fires through CO detection. We studied the diffusion law of CO gas directly above covered smoldering charcoal as a criterion to design a detection device equipped with multiple CO sensors. According to the motion decomposition search algorithm, the detection device realizes the function of automatically searching for smoldering charcoal. Experimental data shows that the average CO concentration over the covered smoldering charcoal decreases exponentially with increasing height. The size of the search step is related to the reliability of the search algorithm. The detection success corresponding to the small step length is high but the search time is lengthy which can lead to search failure. The introduction of step and rotation factors in search algorithm improves the search efficiency. This study reveals that the average ground CO concentration directly above smoldering charcoal in forests changes with height. Based on this law, a CO gas sensor detection device for hidden smoldering fires has been designed, which enriches the technique of residual fire detection.

Key words: Forest fires, Smoldering fire detection, Wood carbon smoldering, CO sensor