- Article
This study investigates stable downstream-pool ignition, combustion-coupling enhancement, and radiative characteristics of separated tandem square ethanol pool fires under longitudinal wind. Experiments employed two pool sizes, four spacings (5–15 cm), and five wind speeds (0.7–2.5 m/s), together with corresponding single-pool baselines. Mass loss rate, local heat flux, and flame geometry were measured. Equivalent total heat feedback was inferred from the steady-state mass loss rate, while local and area-averaged incident radiation were evaluated using a tilted-flame view-factor model. Three apparent-emissivity correlations based on heat release rate, dimensionless pool diameter, and optical length were compared. Stable downstream burning was governed mainly by wind speed and spacing. Once stable burning was established, coupling enhancement did not increase monotonically as spacing decreased. For the 15 cm × 15 cm pool, the optical length and area-averaged view factor both peaked at S = 7 cm within the investigated spacing range, coinciding with the maxima in area-averaged incident radiative heat flux and mass loss rate. The optical-length-based emissivity model showed the most stable agreement with local heat-flux measurements. These results suggest that the enhanced burning response at S = 7 cm is associated with the combined effects of flame radiative capacity and geometric coupling under the investigated conditions.
14 November 2026





