Analysis of flame characteristics of low calorific value gas diffusion combustion under the action of thermal dynamics

Abstract

In this paper, the flame characteristics of co-axial concomitant flow diffusion combustion of low calorific value gas under the action of thermal dynamics are studied. Based on Fluent software, the combustion process of low calorific value gas is simulated by a finite element volume method. According to different air preheating temperatures $T{a}_{in}$, by analyzing the changes of temperature field, velocity field and concentration field during combustion and solving the curve fitting equation of velocity field, the changing trend of the flame core, inner flame and outer flame with air preheating temperature is obtained. The results show that the flame front temperature decreases with the increase of $T{a}_{in}$ when low calorific value gas is burned; the flame core and the inner flame length shorten with the increase of $T{a}_{in}$. When $T{a}_{in}$ rises from 300 K to 500 K, the flame core and the inner flame shorten by 0.05584 and 0.05867 m respectively, with the increase of $T{a}_{in}$, the length of the flame outer flame increases first and then decreases. when $T{a}_{in}=350K$, the flame outer flame is the longest with the maximum value of 0.78865 m m. When $T{a}_{in}=350K$, The $Y_{\text{max}}$ value corresponding to the zero-boundary point position of the equivalence ratio of combustion reaction is the largest, and the maximum value is $Y_{\text{max}}=0.0328\text{m}$. Therefore, when $T{a}_{in}=350K$, the flame outer flame length is the longest, the mixing area of combustible gas and air is the largest, the flame front temperature is higher during combustion, and the combustion effect is the best.

Keywords:

• low calorific value gas
• air preheating temperature
• diffusion combustion
• curve fitting
• flame characteristics

Acknowledgements

The authors gratefully acknowledge the contribution of the project research of Kinetics behavior of particular matter resulting from the oil mist burning with in porous media and Research and development of combustion technology and equipment in porous medium of Low calorific value gas.

Disclosure statement

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

Additional information

Funding

This work was supported by the Natural Science Foundation of Hunan Provincial [grant number 2017JJ2266]; Changsha Science and Technology Plan Project [grant number kq1901103].