Ignition Characteristics of Methane and Hydrogen Using a Plasma Torch in Supersonic Flow

Optimization of double plasma jet torches in a scramjet combustor

“…1. Details of the structure of these torches have been previously reported [5,7]. The diameter of the nozzle throat and the mole flow rate of the feedstock for each torch were 1.5 mm and 1.1 · 10 À2 mol/s, respectively.…”

“…A plasma jet (PJ) torch has been extensively investigated as a suitable igniter for the scramjet engine for more than two decades since Kimura et al [1] demonstrated its effectiveness in supersonic airflow. Many researchers have experimentally and theoretically investigated several aspects of the PJ torch, such as the effects of feedstock [2][3][4], locations of the fuel injector and the PJ torch [5,6], and airflow conditions [7] on ignition characteristics, including spectroscopic analyses of the PJ itself [8,9], for both hydrogen and hydrocarbon fuels. Based on results obtained in the past research, the authors originally developed a new configuration of the PJ torch igniter in a previous study [10].…”

Optimization of a Small-Scale Engine Using Plasma Enhanced Ignition

“…These studies have examined: pre-treatment of the fuel or reactants into hydrogen-rich syngas prior to combustion [11][12], enhanced ignition of hydrocarbon fuels [5,10,13], increased stability of combustion at atmospheric pressure [4,[14][15][16] and enhanced combustion efficiency [17]. In particular, plasmas have shown great promise in improving the stability of high-speed ignition and combustion for supersonic propulsion systems [1,3,[18][19][20][21], allowing for operation with greater efficiency, stability and power over a broad range of supersonic velocities. Plasma addition alters the reaction mechanisms by: (1) decomposition of the fuel gas from larger to smaller hydrocarbon molecules and radicals via the electron gas with temperature, T e ; (2) radiation-induced electron excitation [18]; (3) increased adiabatic flame temperature, T af , that increases the rates of reaction and transport; and (4) impact of increased ion/electrons on key radical initiation and propagation reactions.…”

“…When plasma energy is coupled into the reaction zone of a flame as shown in Figure 1, a dramatic increase in electrons and ions impact the reaction pathways and increase the rate of chemical energy conversion. A number of different plasmas, including thermal plasma [19], dielectric barrier discharge [16], nanosecond pulsed discharge [13], pulsed corona discharge [23], RF discharge [17], DC or low frequency AC discharges [24], plasmatron [25] and microwave discharge [26] have been demonstrated in the laboratory. A more extensive review can be found in [2].…”

An Experimental Approach using Plasma Jets to Realize the Radicals' Effects for Improving Ignition and Combustion

“…Numerous studies using plasma jets for promoting combustion have been conducted, but most target selecting the best performance conditions for a given practical situation, such as a given flow Mach number and pressure in an ignition experiment to develop a supersonic ramjet (SCRAM) engine. [3][4][5][6][7][8] The objective of this study is to propose and design an experimental apparatus with a plasma torch capable of investigating the effectiveness of radicals for premixed gas combustion at relatively low speeds, with which the roles of different radicals in combustion can be compared in as general manner as possible. The effectiveness of radicals was evaluated from the input electrical power necessary for the limits of ignition and combustion sustenance using this original apparatus throughout the study.…”