Simulation Of Multi-Component Gas Flow and Heat Flux in Fire Ventilation Systems Using Ansys Fluent

Abstract

Fire events in enclosed environments generate high-temperature multi-component gas mixtures consisting primarily of nitrogen, oxygen, carbon dioxide, water vapor, and toxic combustion products. Accurate prediction of gas dispersion, buoyancy-driven flow, and heat flux distribution is essential for safe ventilation system design. This study presents a Computational Fluid Dynamics (CFD) investigation of multi-component gas flow and thermal transport in fire ventilation systems using ANSYS Fluent. The governing equations for mass, momentum, species transport, and energy conservation are solved under buoyancy-driven turbulent conditions.

The numerical model evaluates:

• Temperature distribution


• Heat flux evolution


• Species concentration fields


• Buoyancy-induced circulation


• Ventilation efficiency

Results demonstrate strong coupling between temperature gradients and density variation, confirming buoyancy as the dominant driving mechanism in fire-induced ventilation flows.