Numerical Modeling of Steady Smoldering Propagation in Slim Char Rods Characterized by Oxidation of Char Cone

ABSTRACT

To clarify the mechanism on natural steady smoldering, propagation of smoldering in slim char rods was investigated theoretically and experimentally. A numerical model of smoldering propagation in char rods characterized by oxidation of char cone (the conical reaction zone) was developed based on energy conservation as well as oxygen transport through ash and flue gas. Shape and temperature field of char cone were calculated via Gauss–Seidel iteration, and sensitivity analysis of parameters was performed. Experiments on propagation velocity, shape and temperature field of char cone were also performed using char rods with different materials and diameters to validate the model. It is found that the predicted results agree well with the experimental results, indicating that the model is able to describe steady propagation of smoldering of char rods appropriately. The main parameters affecting the height and temperature of char cone are activated energy of fuels and ambient pressure, respectively, and the height of char cone is more sensitive than temperature to the parameters.

KEYWORDS:

• Char rods
• steady
• smoldering propagation
• char cone
• numerical modeling

Acknowledgements

The authors acknowledge the financial supports provided by National Natural Science Foundation of China (grant no. 51676115), Sino-German Center for Research Promotion (grant no. M-0183), Natural Science Foundation of Shandong (grant no. ZR2022ME038), and innovation ability improvement project of small and medium-sized technology-based enterprises (grant no. 2021TSGC1114).

Disclosure statement

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

Supplemental material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/00102202.2023.2243540.

Additional information

Funding

The work was supported by the National Natural Science Foundation of China [51676115]; Natural Science Foundation of Shandong Province [ZR2022ME038]; Innovation ability improvement project of small and medium-sized technology-based enterprises and it is funded by Department of Science and Technology of Shandong Province [2021TSGC1114]; Sino-German Center for Research Promotion and it is funded by Sino-German Center for Science [M-0183].