Effect of hydrogen addition on flame stability and structure for low heating value coaxial nonpremixed flames

ABSTRACT

An investigation of effect of hydrogen addition on flame stability and structure i.e. combustion characteristics of low heating value gases (LHVGs) that consist of methane, propane, nitrogen is carried out experimentally and numerically. For the experiment, a coaxial non-premixed jet-type combustor and Planar Laser Induced Fluorescence (PLIF) system are used to evaluate the flame stability limit and flame shapes and visualize OH radical distribution, respectively. For the numerical analysis of hydrogen added LHVGs, the calculation using the FLUENT software with decreased GRI 3.0 mechanism is performed to study the 2D flame temperature distribution and radial flame structure. As a result, the flame length of LHVGs reduces as hydrogen is added. CH* and OH* radicals visualized by chemiluminescence system are distributed closer to the nozzle as hydrogen is added to LHVGs. OH-PLIF images show that OH intensity of LHVG 6000 is higher with hydrogen addition. The flame stability of LHVGs is improved with hydrogen addition. As for the numerical result, the reduction of flame length and width of LHVG 6000 are predicted with adding the hydrogen.

KEYWORDS:

• Low heating value gas
• coaxial flow
• non-premixed flames
• flame stability limit
• flame structure
• hydrogen addition

Acknowledgments

This work was supported by Basic Science Research Program through the NRF funded by the Ministry of Education (Grant Number: NRF-2018R1D1A1A09083076) and by Research Base Construction Fund Support Program by Jeonbuk National University in 2019.

Disclosure statement

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

CRediT author statement

C. Shin: Investigation, Software, Data Curation, Writing- Original draft preparation. H. T. Nam: Investigation, Software, Data Curation. S. Lee: Conceptualization, Methodology, Supervision, Writing - review & editing