Effects of component variation of natural gas on its premixed flame propagation characteristics
(2.School of Energy and Power Engineering, Wuhan University of Technology, Wuhan, Hubei, China 430063)
【Abstract】The constant-volume combustion vessel and CHEMKIN PRO software were employed to investigate the effects of component variation of natural gas on the laminar burning velocity and flame instability at the ambient temperature and pressure and the stoichiometric ratio. The results show that the laminar burning velocity of natural gas rises with the increase in ethane content, propane content and n-butane content, and the effect of the variation of ethane content on the laminar burning velocity is the most obvious. The instabilities of natural gas–air flames are decreased with the increase in ethane content, propane content and n-butane content. For inhibiting the overall instabilities of natural gas–air flames, the ability of n-butane is approximately equal to the ability of propane, both of which are greater than that of ethane. The flame structure analysis shows that the variation of the peak value of mole fraction of the radical H is the most significant when the natural gas composition fluctuates. There is a strong correlation between the laminar burning velocity of natural gas and the maximum values of the sum of mole fractions of OH and H. The sensitivity analysis of the laminar burning velocity and the net-reaction-rate analysis show that the natural-gas component variation affects the important elementary reactions. The competition between the elementary reactions with positive impacts and the ones with negative impacts varies the peak of the H mole fraction and the variation of ethane content has the greatest effect on the mole fraction of H radicals.
【Keywords】 natural gas; component variation; constant-volume combustion vessel; chemical kinetics; premixed flame propagation characteristics;
(Translated by HAN R)
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