Investigation on the combustion behavior and thermal radiation model of methanol pool fires under crosswind

• Critical values for the transition in combustion behavior were proposed. • A universal dimensionless parameter set for flame morphology was developed. • The temperature field distribution and flame temperature were analyzed. • Tilted cylinder model was optimized by considering flame base extension. This study systematically investigates the combustion behavior, flame morphological parameters, and flame temperature distribution of methanol pool fires under cross air flow. Furthermore, modifications to the tilted cylinder solid flame model were also proposed by accounting for flame base extension. The study covered crosswind speeds from 0 to 2.00 m/s and pool fire diameters from 0.20 m to 0.60 m. Flame characteristic parameters, flame temperature distribution and radiative heat flux were quantified and analyzed. The results indicate that the methanol pool fire began to tilt at Fr = 0.12, and the flame base started to extend at Fr = 0.26. By incorporating the driving effect of vortex-induced buoyancy, the characteristic flame parameters were correlated with a unified set of dimensionless numbers. As the crosswind speed increases, the region of maximum temperature shifts from the bottom core area just above the liquid surface along the flame axis toward the downwind direction, moving slightly away from the liquid surface. With further increase in crosswind speed, the maximum flame temperature appears in the region near the upwind side of the flame base. The incorporation of the flame base center and equivalent diameter enhances the reconstruction capability of the tilted cylinder model for actual radiation fields, reducing the prediction error of radiant heat flux to within 20%.