An investigation of important gas-phase reactions of nitrogenous species from the simulation of experimental measurements in combustion systems

TLDR: In this article, simulated results from a detailed elementary reaction mechanism for nitrogen-containing species in flames consisting of hydrogen, C1 or C2 fuels are presented, and compared with bulk experimental measurements.

About: This article is published in Combustion and Flame.The article was published on 2001-03-01 and is currently open access. It has received 59 citations till now. The article focuses on the topics: Combustion & Elementary reaction.

Figures

TABLE 2

Fig. 4. [NO] and [NH] profiles in a 20 Torr stoichiometric H2/N2O/Ar flame [15].

Fig. 5. [NO] profiles in a rich (F 5 1.5) H2/air flame at 38 and 78 Torr [16].

Fig. 6. [HCN], [NO] and [N2O] from HCN oxidation in a flow reactor at 1.05 atm: (a) 298 ppm HCN, 1620 ppm CO, 434 ppm NO, 2.3%O2, 2.6%H2O, balance N2; (b) 303 ppm HCN, 447 ppm NO, 2.3%O2, 2.7%H2O, balance N2.

Fig. 8. [NO] and [N2O] in a jet-stirred reactor fed with a lean (F 5 0.52–0.62) mixture of methane and air at 1 atm [19].

Fig. 7. [NO] in a jet-stirred reactor fed with methane and air mixture at 1 atm at 1655 to 2020 K [18]: (a) NO production; (b) NO retention when doped with 1300 ppm of NO.

Frequently asked questions

Q1. What have the authors contributed in "An investigation of important gas-phase reactions of nitrogenous species from the simulation of experimental measurements in combustion systems" ?

In this paper, the authors compare the performance of the GRI-mech 3.0 and 3.11 reaction mechanisms with the results of a large number of experimental measurements. 

Q2. What are the future works in "An investigation of important gas-phase reactions of nitrogenous species from the simulation of experimental measurements in combustion systems" ?

The reactions showing high sensitivities and significant variations between mechanisms have been highlighted, thereby indicating where further experimental work is required to determine rate coefficients and product channels. ● Further experimental studies of this type would greatly facilitate the evaluation of complex mechanisms and would provide a more demanding set of target data for optimization. 

Q3. What is the role of NOx in the combustion process?

The chemical mechanism for the gas phase production and destruction of NOx is an important part of the design of low NOx systems. 

Q4. What is the rate coefficient used in the Leeds NOx mechanism?

A much faster rate coefficient is used in the Leeds NOx mechanism, based on the shock tube experiments of Mertens et al. [26] who measured the overall rate of reaction, and proposed product branching ratios that make this channel important. 

Q5. What is the name of the group that evaluated the rate coefficients?

Some of the rate coefficients have been evaluated by the CEC (Commission of European Communities) groupevaluating kinetic data for combustion modeling, providing temperature and pressure-dependent rate coefficients with uncertainty estimates [4] and henceforth referred to as the CEC evaluation. 

Q6. What is the rate coefficient of reaction 28?

Reaction 28, as discussed in ‘Reactions of HCN’, has a positive sensitivity with respect to NO, and the rate coefficient is already at its upper limit, giving little scope for achieving an improvement in the simulations by its adjustment. 

Q7. How many times has the rate coefficient been reduced by Miller?

The rate coefficient used in both the Leeds NOx mechanism and GRImech 3.0 was obtained from an estimate of Miller et al. [12], although in GRI-mech 3.0 it has been reduced by a factor of four by their optimization process. 

Q8. What is the agreement between the measured and computed values in Fig. 8?

The agreement between computed and measured values in Fig. 8 is good, with only a slight over-prediction of [NO] across the temperature range. 

Q9. What are the reactions showing high sensitivities and significant variations between mechanisms?

The reactions showing high sensitivities and significant variations between mechanisms have been highlighted, thereby indicating where further experimental work is required to determine rate coefficients and product channels. ●