The initiation of a detonation in Pulse Detonation Engines (PDE) has been identified as one of the critical and enabling technologies for PDEs. In particular, the initiation of practical fuel-air mixtures containing liquid droplets without supplementary oxygen or other high loss mechanisms is a capability that could enable the PDE to exceed the performance of ramjets and expendable turbo-machinery based systems. Although many past engine concepts have relied upon sensitive fuel/oxygen initiator units or unrealistic gaseous fuels such as hydrogen and ethylene, the split-path PDE has been designed to enable the use of JP-10, a high-density liquid fuel. Flow through segments of the combustor was both modeled with a compressible flow solver and experimentally evaluated in the laboratory at simulated flight conditions. A spiral-lined initiator demonstrated a significantly lower total pressure loss when compared to a ring-lined version, and thus was the preferred initiator configuration. Experimental values for the turbulence were found to be significantly lower than the computed values at similar conditions when using a k-e model. Finally, successful ignitions of the JP-10/Air initiator were achieved up to refresh Mach numbers of 0.13 at inlet pressures and temperatures of 150kPa and 550 K, respectively. The increase head-end recirculation/rotational regions with 60-degree versus the 45-degree side dump angles of the inlet arms substantially improved the ignition success rate.
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