Laminar and kinetic burning characteristics of ethanol/methane/hydrogen fuel: Experimental and numerical analysis

Abstract

In this essay, the effects of ethanol addition on the fuels of Hydrogen methane mixing fuel were discussed. The laminar burning characteristics of ethanol/hydrogen/methane mixture under different ethanol content, pressure (1 bar, 2 bar), and equivalence ratios (0.7–1.4) were experimentally and numerically simulated. Results show that increasing ethanol content reduces the laminar burning velocity (LBV) and shifts the peak LBV towards higher equivalence ratios, attributed to the fuel mixture's decreased average combustion heat. For a 20 % ethanol content, the LBV peak appears at φ = 1.3, while for 50 % and 80 % ethanol content, it appears at φ = 1.2 locations. An empirical correlation for LBV as a function of ethanol concentration was developed, demonstrating predictions within a 4 % error margin compared to experimental data. High accuracy fittings of activation energy, ethanol concentration, and equivalence ratio were achieved, with correlation coefficients exceeding 0.9. Numerical simulations pinpointed key reactions and the relationship between free radicals and LBV, highlighting a pronounced correlation between OH radicals and LBV under lean conditions (coefficient of 1.0583), and a strong correlation with H radicals under rich conditions (coefficient of 1.01657), this indicates that OH and H are involved in the key chain reaction that promote the burning process.