Ignition and Dentonation Characteristics of Hydrogen and Hydrocarbon Fuels in a PDE
Abstract
Over the past two decades, several fuels have been tested in pulsed detonation engines (PDEs) throughout the world. This research focuses on developing a baseline set of ignition and detonation performance measures for six distinct fuels in air: Hydrogen, ethylene, propane, aviation gasoline (avgas), JP-8, and Fischer-Tropsch JP-8 (S-8). To quantify the ignition and detonation performance, four parameters are examined: Ignition time, deflagration- to-detonation transition (DDT) time, DDT distance, and the upper Chapman-Jouguet (CJ) wavespeed. Those four parameters are presented as a function of equivalence ratio from lean to rich flammability limits for all six fuels. Hydrogen was found to have the best ignition and detonation characteristics, followed by ethylene. Propane, avgas, JP-8, and S-8 exhibited similar ignition and detonation characteristics, as expected based on cell size. Minimum ignition times for all fuels occurred near an equivalence ratio of 1.3, while the minimum DDT times and distances occurred between equivalence ratios of 1.1 and 1.2. All experimental CJ wavespeeds were within 5% of the theoretical CJ wavespeed with the exception of hydrogen, which was systematically between 6% and 8% lower than the theoretical value.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2007
- Accession Number
- ADA473507
Entities
People
- Fred Schauer
- John Hoke
- Royce Bradley
- Tim Heifrich
Organizations
- Air Force Research Laboratory