Numerical Simulation of Hydrogen and Methane/Hydrogen Combustion in Micro-burners

doi:10.12068/j.issn.1005-3026.2024.08.004

Abstract

Abstract:

In order to achieve stable combustion of gas in micro?burners and obtain high and uniform temperature distribution on the outer wall， a combustion model of gas in micro?burners with backward steps was established. Firstly， the influence of the number of backward steps on micro?combustion was studied. Secondly， the combustion characteristics of methane/hydrogen in micro?burners with three backward steps under different hydrogen ratios were studied. The results show that the backward step structure can stabilize the flame. When the inlet velocity of the gas is 3 m/s， the equivalent ratio range （0.3~5.0） of the gas with three backward steps is larger than that （0.5~4.6） with one backward step. Although the backward step structure increases the temperature of the outer wall， the temperature difference of the outer wall becomes larger， and the temperature uniformity is reduced. Adding a certain proportion of methane to hydrogen not only slows down the combustion reaction rate of the mixture， but also obtains higher outer wall temperature and energy output.

Key words: microscale combustion, backward step, blended combustion, combustion characteristics, steady combustion

CLC Number:

TK 16

Xin-ru SUN, Yue SUN, Fu-sheng YAN, Hui LIU. Numerical Simulation of Hydrogen and Methane/Hydrogen Combustion in Micro-burners[J]. Journal of Northeastern University(Natural Science), 2024, 45(8): 1088-1095.

Figures/Tables 14

Fig. 1 The geometry of micro?burners with different backward steps

Fig. 2 Gas temperature distribution on the center line of micro?burners under models of different grids

Fig. 3 Comparison between simulation and experimental results

Fig. 4 XY plane temperature cloud images and gas streamline distribution of micro?burners

Fig. 5 Distribution of centerline gas temperature and

Fig. 6 The ranges of combustion equivalent ratio for different micro?burners

Fig. 7 Outer wall temperature distribution of micro‐ burners with different backward steps

Fig. 8 Combustion efficiency of hydrogen in micro‐ burners with different backward steps

Fig. 9 Temperature cloud map and contour distribution of XY plane at different hydrogen ratios

Fig. 10 Kinetic rate under different hydrogen ratios

Fig. 11 Temperature distribution on the outer wall of micro?burners under different hydrogen ratios

Fig. 12 Schematic diagram of the micro?thermo? photovoltaic system

Fig. 13 Influence of hydrogen ratio on energy output

Fig. 14 Energy efficiency under different hydrogen ratios

References 15

1	Yang W M， Chou S K， Shu C，et al.Development of a prototype micro‑thermophotovoltaic power generator［J］.Journal of Physics D：Applied Physics，2004，37（7）：1017-1020.
2	Spadaccini C M， Mehra A， Lee J，et al.High power density silicon combustion systems for micro gas turbine engines［J］.Journal of Engineering for Gas Turbines and Power，2003，125（3）：709-719.
3	Norton D G， Vlachos D G.A CFD study of propane/air microflame stability［J］.Combustion and Flame，2004，138（1/2）：97-107.
4	Pan J F， Zhang C X， Pan Z H，et al.Investigation on the effect of bluff body ball on the combustion characteristics for methane/oxygen in micro combustor［J］.Energy，2020，190：1-11.
5	Tang A K， Xu Y M， Pan J F，et al.Combustion characteristics and performance evaluation of premixed methane/air with hydrogen addition in a micro‑planar combustor［J］.Chemical Engineering Science，2015，131：235-242.
6	Tan Y， E J Q， Chen J W，et al.Investigation on combustion characteristics and thermal performance of a three rearward‑step structure micro combustor fueled by premixed hydrogen/air［J］.Renewable Energy，2022，186：486-504.
7	Peng Q G， Wu Y F， E J Q，et al.Combustion characteristics and thermal performance of premixed hydrogen‑air in a two‑rearward‑step micro tube［J］.Applied Energy，2019，242：424-438.
8	Yang W M， Chou S K， Shu C，et al.Microscale combustion research for application to micro thermophotovoltaic systems［J］.Energy Conversion and Management，2003，44（16）：2625-2634.
9	Su Y， Cheng Q， Song J L，et al.Numerical study on a multiple‐channel micro combustor for a micro‑thermophotovoltaic system［J］.Energy Conversion and Management，2016，120：197-205.
10	Tang A K， Pan J F， Yang W M，et al.Numerical study of premixed hydrogen/air combustion in a micro planar combustor with parallel separating plates［J］.International Journal of Hydrogen Energy，2015，40（5）：2396-2403.
11	Peng Q G， Wei J， Yang W M，et al.Study on combustion characteristic of premixed H₂/C₃H₈/air and working performance in the micro combustor with block［J］.Fuel，2022，318：123676.
12	Jiang D Y， Yang W M， Teng J H.Entropy generation analysis of fuel lean premixed CO/H₂/air flames［J］.International Journal of Hydrogen Energy，2015，40（15）：5210-5220.
13	Tang A K， Ni Q， Deng J，et al.Role of hydrogen addition in propane/air flame characteristic and stability in a micro‑planar combustor［J］.Fuel Processing Technology，2021，216：106797.
14	Law C.Effects of hydrocarbon substitution on atmospheric hydrogen‑air flame propagation［J］.International Journal of Hydrogen Energy，2004，29（8）：867-879.
15	许艺鸣，单春贤，唐爱坤，等.微型燃烧器内掺氢甲烷燃烧特性的数值模拟［J］.机械工程学报，2015，51（18）：151-157.
	Xu Yi‑ming， Shan Chun‑xian， Tang Ai‑kun，et al.Numerical simulation of methane combustion characteristics with hydrogen addition in a micro‑combustor［J］.Journal of Mechanical Engineering，2015，51（18）：151-157.