The coverage of combustion zone based on graded Particles: Analysis of gap structure and mechanism

The complete coverage of the combustion zone by particles is crucial for extinguishing fires. This study explores the coverage effect on the boundary of combustion zone and the complex gap structure between particles. A method of using graded particle for fire extinguishing is proposed. The gap structures between particles and the boundary of combustion zone are studied. The results show that, firstly, under the same radius of the combustion zone (RCZ), when the RCZ is 100px, the radius of particle (RP) increases from 1px to 10px, the area of all particles (TAAP) becomes 9.8 times, and the area of area between particles and combustion zone boundary (TAGPCZB) becomes 7.14 times. As RCZ increases, TAGPCZB also slightly decrease, and the maximum reduction in gap ratio is about 1.55%. The maximum gap between particles is about 100.16 times of the minimum gap. As the area of the combustion zone (TACZ) increases, the coverage rate of combustion area (CRCA) also increases. When RCZ is from 1000px to 2000px, a maximum of coverage rate is 78.552%. In addition, the mechanism of graded particles covering the combustion zone is proposed. This study provides theoretical support for the application of graded particles for covering the combustion zone.