Radiation heat flux of the open-cellular porous gas burner

Abstract

Radiation heat flux from the combustion of the methane-air premixed gas on an open-cellular porous burner
was investigated experimentally and numerically. In the experiment, an alumina-cordierite (Al-Co) having
pores per inch (PPI) of 20 and porosity (φ) of 0.875 was examined. Radiant output from the porous burner
was measured based on a two-color radiometry. For the analysis, we assumed that the chemical kinetics of
gas-phase (Energy equation) reactions was governed by a single-step Arrhenius rate expression. To evaluate
the radiative transports in the solid-phase energy equation, the equation of transfer for the radiation field in a
porous burner was solved using the P1 approximate method. The stable combustion of the present burner
was characterized by flash-back limits, where the equivalence ratio (Φ) was around 0.48 to 0.5, and blow-off
limits (Φ was around 0.58 to 0.64). The radiant outputs depended on Φ and Reynolds number (Re).
Predicted results of the dimensionless forward radiative heat flux (Ψ+) and the burner surface temperature
(TS) were reasonably compared with experimental data. Reasonable agreement between theory and
experiment was obtained, and thereby the validity of the present theoretical model for predicting the radiation
from a porous burner was confirmed.