Numerical Simulations of the Influence of Inert Gases (N₂/CO₂) on Combustion Characteristics of Laminar-Premixed Biosyngas Flame

Abstract

In this work, the influence of different N2/CO2 contents (up to 60% in fuel volume) on combustion features of laminar-premixed CO/CH4/H2 flame with various equivalence ratios (0.6–1.6) at standard conditions was numerically calculated using ANSYS CHEMKIN-PRO with the GRI-Mech 3.0 mechanism. The mole fraction profiles of the major species and the rate of production of dominant elementary reactions in the flames of CO/CH4/H2/N2/CO2/air were obtained. The effect of inert gas addition on the formation of NO X , H, O, and OH was analyzed, and the sensitivity coefficient of the active radical mole fraction was obtained. The results suggest that the addition of inert gas of the fuel mixture with various equivalence ratios reduces laminar burning velocity and adiabatic temperature, which have always had a good positive correlation and the maximum peak point shifted left. CO2 has obvious inhibitory effect on the formation of NO by reducing the amount of O radicals and obstructing the conduct of the reaction of NNH + O ⇔ NH + NO, but it promotes the formation of NO2 mainly through the reaction HO2 + NO ⇔ NO2 + OH. The reactions H + O2 + H2O ⇔ HO2 + H2O, H + O2 ⇔ O + OH, and OH + CO ⇔ H + CO2 are three very important reactions for the molar fractions of H, O, and OH that decrease significantly with an increase of inert gas concentration.

Numerical Simulation of the Influence of CO2 on the Combustion Characteristics and NOX of Biogas

“…Assuming that the gas inlet is a one-dimensional steady flow, the governing equation can be simplified as follows (Kuo, 2005;Sun et al, 2021):…”

“…The results showed that the laminar flame speed has a good positive correlation with the adiabatic temperature under different equivalent ratios. The inhibition effect of CO 2 is stronger than N 2 , which may be related to the chemical effect and heat capacity of CO 2 (Sun et al, 2021). It can be seen from the above that the change of CO 2 concentration has a stronger influence on combustion characteristics than N 2 , and most scholars have studied the influence of inert gas on combustion characteristics of simple components (methane, methane-air mixture, etc.).…”

An Analysis of the Static and Dynamic Behavior of the Hydraulic Compensation System of a Multichannel Valve

“…Therefore, in this study, an electrohydraulic proportional control valve was selected as the research object, and an advanced international reversing valve was selected as the reference object [27][28][29][30][31]. A mathematical model of the pressure compensation system was established using the power bond diagram method.…”

Methane–Air Plasma-Assisted Ignition Excited by Nanosecond Repetitively Pulsed Discharge: Numerical Modeling and Effect of Inert Gas

“…Investigations on the effects of different inert gas dilutions on the combustion processes have been conducted, which illustrates that the dilution of inert gas has distinctive influences on the energy deposition and the kinetic coefficient of methane–air plasma in the ignition process. − In addition, Yi et al have indicated that different diluent concentrations have a significant impact on the flame structure and the soot flame temperature . Mohammad et al have proved that the burning velocity decreases with the increase in percentage of inert gas .…”

“…Moreover, Ar and He are suitable feed gases for the research of the effect of inert gas dilution on the methane–air PAI due to their easy acquisition and low cost. Sun et al and Liu et al have conducted studies on combustion characteristics, the results of which showed that the addition of inert gases like N 2 /CO 2 or Ar to the fuel mixture can appropriately control the flame temperature and the species generated from He-diluted fuel has lower oxidation reactivity. , Zhang et al have pointed out that the dilution of Ar not only can keep the cycle-by-cycle variations of the tested engine unchanged but also is beneficial for the mean effective pressure . Since the inert gas dilution has significant influences on the PAC and Ar and He are the general and appropriate inert gases, the present study takes the inert gases Ar and He into account.…”