Dual-pulse laser ignition model

Abstract

A two-dimensional mathematical model of dual-pulse laser ignition that self-consistently integrates Navier-Stokes, translational and vibrational energy, and neutral and charged species equations has been presented. The results showed that the ignition kernel dynamics depends on the shape and initial energy distribution in the energy spot created by the first ultraviolet laser pulse. The results also suggest that the ignition delay time and the flame kernel development depend on the laser intensity, vibrational-nonequilibrium, and initial electron number density. For the high initial degree of ionization, we have obtained ignition of the lean methane–air mixture with the equivalence ratio of 0.6. Vibrational-nonequilibrium taken into account by the Landau-Teller model leads to the slower ignition kernel growth and the significant increase in the ignition delay time. For the case modeled, a change in the overlap of the second laser with the focal point of the first laser pulse leads to the early split up of the kernel and the flame extinguishment.

Flamelet modeling of plasma and ignition process in a variational LES computational method

“…The proposed study will also include the influence of vibrational and electronic energy transfer mechanisms during the nonequilibrium energy deposition and thermalization process during the equilibrium energy deposition (e.g. Spark) [7]. The electron-induced reaction rates, electron species transport parameters, mobility and diffusivity, and the electron energy mobility and diffusivity and the ions and neutrals can be treated hydrodynamically in a CFD code.…”

“…The initial results suggested that the electron, vibrational, and gas temperatures quickly (~100 ns) reach a steady-state condition, which can not be captured by conventional modeling approaches. Besides, the time at which the electron temperature reaches a steady state is related to plasma lifetime and strongly relies on energy deposition rate [7]. However, the initial calculations suggested that the vibrational-translational energy exchange mechanism is much slower than the electronic-translational and electronic-vibrational process.…”

Gasdynamic Flow Control by Ultrafast Local Heating in a Strongly Nonequilibrium Pulsed Plasma

“…The ability to control the energy deposition can be especially valuable in gas flow control problems. In addition, this approach turned out to be in demand for plasma-stimulated ignition and combustion [86,89].…”

“…Возможность конроля за вкладываемой энергией может оказаться особенно ценной в задачах управления потоками газа. Кроме того, этот подход оказался востребованным и для стимулированного плазмой воспламенения и горения[86,89].…”

Resonant dual-pulse laser ignition technique based on oxygen REMPI pre-ionization

“…A computational fluid dynamics (CFD) analysis has shown the role of plasma-driven gas dynamics to enhance the early kernel growth, in particular an ability to tailor the resulting laser plasma (by adjusting the axial offset of the two laser pulses) to either suppress or admit the typical 3rd lobe feature which in turn is linked to the ability to ignite lean mixtures 16 . Kinetic modeling has examined nonequilibrium and electron dynamics in the dual-pulse preionization laser plasmas 17 .…”