Numerical Study of the Turbulent Burning between Vertical Parallel Walls with a Fire-Induced Flow

Abstract

A numerical study is conducted to investigate the fire structure, heat transfer and pyrolysis rate between vertical parallel burning surfaces with a fire-induced flow. The strong coupling of the two initially unknown important parameters, such as the burning and fire-induced mass flow rates, is modeled using a parubolized numerical technique which takes account the effects of the streamwise pressure gradient in parallel configuration. Transport equations for mass, momentum, gas-phase chemical species, enthalpy are solved using a finite volume method. The turbulent flow field is solved using a standard k - φ turbulence model in conjunction with a wall function. A two-dimensional adaptation of the discrete ordinates method is used for estimating the flame radiation energy to the burning wall. Soot model is also included in order to permit application to radiative heal transfer within a flame. The results indicate that with decrease of the wall spacing/height ratio (L/H), convection flux decreases slightly, whereas, contribution by radiation increases considerably from 70 to 90 percent of the total heat feedback to the pyrolyzing surface. Of particular interest is a maximum local burning rate for a wall spacing/height ratio (UH≈0.1) due to enhanced convection and radiation fluxes.

Keywords:

• vertical parallel wall fire
• turbulent burning
• fire-induced flow
• parabolized procedure

Additional information

Notes on contributors

H.Y. WANG

Correspondence Author.