<p> The wave dynamics within a rotating detonation engine were investigated using a combustor where the fuel injector was varied continuously relative to the oxidizer throat. Both natural gas and a hydrocarbon fuel blend containing the major components of a "cracked" kerosene fuel were characterized using high speed imaging, pressure sensors, and photomultiplier tubes. Major detonation features were visualized with high-speed cameras through a 360 optical outerbody. The detonation region, oblique shock, contact surface where fresh reactants mixed with products of a previous wave, and burning above the fuel injectors in a stratified zone beneath the detonation wave were studied as fuel conditions and fuel injector position were changed. As the inner body of the engine was translated away from the oxidizer throat, or started at a position far from the oxidizer throat, the combustor was not able to support coherent detonation behavior. At these points, the region of highest heat release remained close to the fuel injectors, and there was very little heat release processed behind the front edge of the wave compared to the level of deflagrative combustion occurring inside the chamber. The surrogate hydrocarbon blend is more representative of a composition that high speed vehicles would use, so the operability limits of the fuel and the fuel with nitrogen dilution were characterized using a metal and an optical outerbody on the combustor. With a larger amount of ethylene in the fuel composition compared to the amount of methane, the chamber tended towards slower waves and higher wave modes, and the combustor was able to sustain a coherent detonative mode with up to 40% nitrogen. When all chosen fuel blend components were present in the fuel except ethane, the combustion kinetics of the fuel was slowed significantly, and there was a measured decrease in thrust. No fuel tested was able to support coherent detonative modes with 50% nitrogen in the oxidizer. </p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/22688428 |
| Date | 06 June 2024 |
| Creators | Allyson Haynes (15349267) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/thesis/Hydrocarbon_Fuel_Composition_Effect_on_Wave_Dynamics_in_a_Continuously_Variable_Rotating_Detonation_Engine/22688428 |
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