Numerical modelling to study the effect of DC electric field on a laminar ethylene diffusion flame

Liu

et al. 2022

Fire

The electric field fire extinguishing technology is an efficient, clean, and new fire extinguishing technology that can be operated at a long distance. In order to study the synergistic mechanism of “electric-flow-heat” in the process of transverse AC electric field fire extinguishing, the ionic wind formed by the influence of electric field on each charged particle during the burning process of ethanol–air diffusion flame is simulated by the non-premixed combustion model, and the experimental phenomenon of flame quenching in the transverse AC electric field is reproduced by means of numerical simulation. The accuracy of the numerical model was verified by comparing the temperature and flow velocity in the region obtained from the simulation with the data measured in the experiment. According to both simulated and experimental phenomena, we present a hypothesis of how the flame is quenched under the influence of an electric field. The next research directions are: (1) improving the accuracy of numerical simulation by building fine models; (2) studying the dynamic mechanism of real flames by particle image velocimetry technology.

Section: External Electric Field Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Ethanol Air Diffusion Flame Quenching under Transverse AC Electric Field

Liu

et al. 2022

Fire

Front. Heat Mass Transf.

“…The instability of the flame will affect the combustion efficiency of the combustion equipment, generate pollutants, and even cause the combustion equipment to flame out in extreme cases (Massa and Freund, 2017). Hence, the periodic and chaotic motions in flame dynamics that can be observed as a result of flame instabilities are of fundamental importance to present combustion science (Sayed-Kassem et al, 2021;Xu et al, 2022;Bae et al, 2022;Manikantachari et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Asymmetric Phenomenon of Flickering Flame Under Different Co-Flow Velocities

Liu¹,

Yang²,

Zhang³

et al. 2023

In this study, numerical investigations are performed on a partially premixed flame of methane and air in two-and three-dimensional models. Nonlinear method is adopted to illustrate the asymmetric phenomenon that affects the flame stability under various co-flow velocities. According to the results, the mathematical relationship between the flame flickering frequency Stanton number and the dimensionless velocity Froude number has been summarized as St=0.7Fr -0.46 . The bifurcation phenomena under different Reynold numbers are found to have significant influence on the system stability. Two critical bifurcation points, which is when Re=300 and Re=1200, are determined as the onset of breaking the flame symmetry and the onset of chaotic state, respectively. The research on flame flicker characteristics provides valuable reference for engineering applications in stable combustion and other related fields.

“…Discharge plasma excitation approaches, such as gliding arc, 13 alternating current, 14 direct current, 15 radiofrequency, 16 microwave, 17 and dielectric barrier discharge, 18 have been implemented to achieve PAI and PAC. In comparison with these methods, nanosecond repetitively pulsed (NRP) discharge could provide higher power density and high reduced electric field (E/N) to accelerate the energetic electron-generating uniform plasma as well as various chemical reactive components for effective fuel oxidation and significant ignition enhancement.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2021

Plasma-assisted ignition and combustion are promising approaches for controlling ignition enhancement and flame stabilization. The global loosely coupled plasma-assisted combustion kinetic model has been established by combining the ZDPlasKin and ChemKin codes, which is employed to numerically investigate the effects of the inert gas-diluted methane−air nanosecond repetitively pulsed (NRP) plasma on the ignition process. The results indicate that addition of the inert gas is conducive to increasing the chemical reactive species densities in the methane−air NRP discharge plasma. The addition of inert gases affects the generation pathways of plasma species and their corresponding contribution rates. Compared with the methane−air plasma, the dilution of inert gases shows obvious effects on reducing ignition delays, and the dilution of He and Ar decreases the ignition delays by 58.0 and 84.0%, respectively. CH 3 + O 2 = CH 3 O + O and H + O 2 = O + OH are the dominant conducive reactions in the methane−air ignition chemistry. Moreover, the dilution of inert gases has considerable influences on the normalization sensitivity coefficients, especially for the reaction of H + O 2 = O + OH.