Deflected turbulent buoyant jet flame: Flow field measurement and flame geometry prediction
Year: 2025
Type: article
Abstract: This paper investigates the geometrical characteristics and flow structure of deflected turbulent flames in still air. Flame tests were conducted at various initial Froude numbers (Fr 0 ) and flame angles (θ 0 , relative to horizontal orientation). Flow fields within the flames were measured utilizing PIV techniques. Results show that for a fixed Fr 0 , decreasing θ 0 reduces flame length due to enhanced air entrainment. Buoyancy-induced flame deflection creates an asymmetric flow field within the flame. In the upper region, buoyancy and streamline curvature effects promote turbulence generation and transport, triggering a detrainment phenomenon that disrupts velocity distribution self-similarity. Conversely, in the lower region, buoyancy inhibits turbulence generation while preserving this self-similarity. Second-order turbulence quantities increase with rising Fr 0 , indicating higher turbulence levels from momentum and buoyancy effects. Under low Fr 0 conditions, momentum-driven and buoyancy-induced fluctuations jointly induce bifurcation in radial distributions of turbulent normal stresses, which progressively diminishes as Fr 0 increases. Turbulence intensity normalized by peak velocity decreases with increasing Fr 0 , indicating reduced influence from buoyancy. A predictive model for flame geometry is established that accurately reproduces geometrical parameters across varying Fr 0 , θ 0 , and flame scale conditions. Additionally, model predictions elucidate significant effects of buoyancy and streamline curvature on flame turbulence. Predicted trends in turbulence intensity align with experimental observations.
Source: Combustion and Flame
Authors: Wei Gao, Zijian Yan, Jiao Lei, Naian Liu
Language: English
Subfield: Computational Mechanics
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,320
OpenAlex ID: W4413433926