Download or read book Toward Plasma-Assisted Ignition in Scramjets written by and published by . This book was released on 2003 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Air Force plasma ignition program is assessing the prospect of main-fuel ignition with plasma generating devices in a supersonic flow. As the study progresses baseline conditions of operation are being established such as the required operational time of the device to initiate a combustion shock train. The two plasma torches currently under investigation consist of a DC constricted-arc design from the Virginia Polytechnic Institute and State University and an AC unconstricted-arc design based on a modified spark-plug from Polytechnic University. The plasma torches are realistic in size and operate within current power constraints while differing substantially in orifice geometry. In order to compare the potential of each concept the flow physics of each part of the igniter/fuel-injector/combustor system are being studied. In each step of the program, we utilize CFD and experiments to help define and advance the ignition process. To understand the constraints involved with ignition process of a hydrocarbon fuel jet an experimental effort to study gaseous and liquid hydrocarbons is underway, involving the testing of ethylene and JP-7 fuels with nitrogen and air plasmas. Results from the individual igniter studies have shown the plasma igniters to produce hot pockets of highly excited gas with peak temperatures up to (and in some cases above) 5000 K at only 2-kW total input power. In addition ethylene and JP-7 flames with a significant level of OH as determined by OH PLIF were also produced in a Mach-2 supersonic flow with a total temperature and pressure of 590 K and 5.4 atm respectively.