Fundamental spatiotemporal studies in heterogenous fire Spread: Instability Mechanisms and Dynamic Mode Selection

Severe issues related to the fire-spreading phenomenon have led researchers worldwide to try different approaches for simplification. The increase in fire-related accidents has escalated the need for better operating solutions. The work presents, experimental simulations conducted on transitional fire spread to improve knowledge of spread of heterogeneous fires in both space & time. Homemade matchsticks were used as pilot fuel and external energy sources. Different configurations were tested, at varying surface orientations with a fixed number of external energy sources per direction. The effect and spreading phenomenon were observed in pilot fuel ignition and change in spreading rate with insight into localized & global burning. To gain true replication, experiments were conducted on dynamic models linear time-invariant (LTI), linear time- variant(LTV), & effect of spatial non-linearity was studied on non-linear dynamic models viz., NLTI (Non- linear time-invariant) & NLTV (Non-linear time variant) to determine spreading fire behavior & features. Additionally, important probable like, effect of phosphate was examined. The results were compared with single fuel burning to get better insight into external heat source & heat sink effect in both singular & coupled modes. The results reflect turbulent nature of fire spread & disorderly burning process. The spread rate analysis highlights distinct heat source & sink effect, uncertainty involved with collective burning along with combustion instability in form of irregular energy transfer. The results can be utilized in designing effective fire suppressants & retardants within given fire safety norms.