Modeling Concurrent Flow Flame Spread and Extinction over Solid Fuels

This research project is aimed at the model analysis and calculation of concurrent flow flame spread and extinction over solid fuels. To further understand the flame and flow structures, the flame-spreading behaviors and the controlling mechanisms of the spreading flames, the following two research subjects are proposed, considering two different flow conditions. 1. Upward flame spread and extinction over thin solids in low-speed buoyant flows: In natural convective environments, the effects of three environmental parameters on the flame structures, flame spread rates are investigated. The complete extinction boundary (or flammability limits) using gravity level/oxygen percentage or gravity level/atmospheric pressure as coordinates are also computed. In addition, the influence of the buoyant flows induced by different gravity levels and the possibility to use low pressure environments to simulate the microgravity or reduced gravity conditions in a normal gravity environment are explored. 2. Unsteady concurrent flame spread over solids in low-speed forced flows: An unsteady model of flame spread over solids in concurrent flows is constructed in this work to answer the question that whether concurrent flame spreading over thin solids can reach steady state and the reasons for the existence of the steady flame spreading. With the unsteady model, one can study the controlling mechanisms of ignition to flame spreading or ignition then leading to extinction. The results of the modeling calculation are able to be compared with the limited data from current microgravity experiments worldwide, and the model is also capable to be applied for the unsteady fire growth over the thick solid fuels.

Project ID:PB9308-1153
External Project ID:NSC93-2212-E182-007