Thermal Characteristics of Surface Fire Spreading Front Under Ambient Wind

Abstract

Surface fire is the most common form of forest fire, primarily spreading along the forest land's surface and causing damage to nearby low-lying seedlings, shrubs, and the root systems of vegetation at its base. In actual forest fire scenarios, the occurrence of fires is often accompanied by environmental winds due to the typically complex terrain in forested areas. Forest vegetation is densely distributed, and when surface fires encounter obstacles such as tree trunks, the advancing fire front may interact with the tree trunks under the influence of environmental winds. This study focuses on understanding the thermal characteristics of the interaction between the advancing fire front and tree trunks in the presence of environmental winds. To investigate this interaction, temperature measurements are conducted on both sides of the obstacles and in the downstream region of the flame. Additionally, measurements of radiant heat flux are taken in the upper space above the experimental setup. By analyzing flame morphology parameters and experimental measurements, trends in thermal characteristic parameters with spatial position are identified. Regression formulas are developed to describe the temperature difference between the windward and leeward sides of the obstacles and the height above the experimental platform. Furthermore, the influence of flame climbing on radiant heat transfer in the upper space is discussed.