Numerical investigation on lean methane combustion with modified effective thermal conductivity of the porous media

Abstract

In this work, to further optimise the porous media combustion model and explore the combustion characteristics of low-concentration methane in porous media, a thermal non-equilibrium model of porous media combustion is established with modified effective thermal conductivity of the porous media based on the volume average method. The effects of foam ceramics pore density, inlet velocity and wall heat loss coefficient, as well as combinations of different pore density foam ceramics on flame stability were studied. Results show that the predicted temperature profile matched well compared with the experimental data. The temperature inside the burner can be divided into the following four zones: preheating zone, combustion zone, cooling zone dominated by wall heat loss and cooling zone dominated by heat radiation at the burner outlet. Moreover, it was found that the porous media combustion model with modified effective thermal conductivity of the porous media could simulate the flame front shape in different pore density foam ceramics. On the contrary, the flame front shape in the simulation with constant thermal conductivity does not change and remains a uniform radial disc. In addition, the flame is easier to stabilise at the interface of the foam ceramic with different pore densities.

Keywords:

• Numerical simulation
• porous burner
• thermal non-equilibrium
• porous inert media
• flame stability

Acknowledgements

Financial supports from the National Natural Science Foundation of China (Grant No. 52174214 and 51974303), the Key R&D Program of Jiangsu Province (Grant No. BE2020645) and the Fundamental Research Funds for the Central Universities (No. 2020ZDPY0202, No. 2021GJZPY11, 2021YCPY0207) are sincerely acknowledged.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Financial supports from the National Natural Science Foundation of China [grant number 52174214], [grant number 51974303]; the Key R&D Program of Jiangsu Province [grant number BE2020645]; the Fundamental Research Funds for the Central Universities [grant number 2020ZDPY0202], [grant number 2021GJZPY11], [grant number 2021YCPY0207] are sincerely acknowledged.