Operation of a JP10/air pulse detonation engine

Brophy, Chris; Netzer, David W.; Sinibaldi, José; Johnson, Robert Garret

doi:10.2514/6.2000-3591

Cited by 31 publications

(9 citation statements)

References 2 publications

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“…The oxygen-enriched initiator was used to initiate a detonation in the main combustor by transmitting a strong detonation from the initiator exit to the main combustion through a diffraction process. The initiator operated on an ethylene/oxygen/ nitrogen mixture at an equivalence ratio of 1.2 and had an internal volume of 259 cm 3 with a varying cross section previously found to perform well over a wide range of conditions and fuels [8] was increased to 1.24 m for a limited number of the later experiments. Timing of the fuel injection events and ignition sequence was controlled through the use of a BNC 500 pulse generator which enabled a series of Crydom 6203 solid state relays to control the fuel valves and ignition system.…”

Section: Methodsmentioning

confidence: 99%

“…Previous studies [8,9] at the Naval Postgraduate School (NPS) have evaluated ethylene/air, propane/air, and JP10/air mixture requirements and detonation properties in a PDE with a continuous airflow. Ethylene was chosen for most of the fuel distribution studies due to the availability of a spectroscopic fuel measurement system developed at Stanford [10] which uses absorption spectroscopy, tunable diode laser sources, and fiber optics to transmit across the combustor axis at specific locations.…”

mentioning

confidence: 99%

“…Through the use of optical transmission techniques, experimental measurements of the resulting fuel distributions [8,9] have often shown this to be an invalid assumption and that the resulting temporal/spatial fuel distributions were highly nonuniform. The implications of this characteristic can be a significant shift in the resulting specific impulse performance calculations due to the use of incorrect aggregate fuel mass fraction values.…”

mentioning

confidence: 99%

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Fuel Distribution Effects on Pulse Detonation Engine Operation and Performance

Brophy

Hanson

2006

Journal of Propulsion and Power

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The validity and accuracy of performance measurements for pulse detonation engines depend on the ability to accurately measure thrust and fuel mass flow rates during system operation. Experimental tests have revealed that when fuel mass flow rates are calculated by conventional mass metering methods, incorrect values of the aggregate fuel mass in the combustor will often be calculated due to inaccurate assumptions regarding the spatial fuel distribution. The difficulty in predicting the actual fuel distribution affects the ability to achieve reliable detonations for successful operation and introduces inaccuracies directly into the performance calculations. Tunable diode laser and absorption spectroscopy techniques have been applied to provide time-resolved fuel mass fraction measurements and improve the fidelity of the specific impulse calculations. Results show that stratified fuel distributions that begin near stoichiometric at the forward end of the combustor and gradually become fuel lean near the combustor exit produce substantially higher specific impulse values than axially uniform fuel distributions with the same amount of aggregate fuel due to the ability to reliably detonate while operating at an overall lean condition. Axially uniform fuel distributions at the same average equivalence ratio demonstrated lower detonability and accordingly had lower thrust and specific impulse values.

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Fuel Distribution Effects on Pulse Detonation Engine Operation and Performance

Brophy

Hanson

2006

Journal of Propulsion and Power

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“…The PDE operating environment imposes severe constraints on the fuel injection, atomization, evaporation, and mixing process. For example, Brophy et al [1,2] showed that the droplet Sauter mean diameter should be less than 3 m for successful deflagration-todetonation transition (DDT) at cold start conditions. In addition, the injector must be able to operate at frequencies of up to 100 Hz with no-drip shutoff so as to avoid premature deflagration during the purge/fill cycle.…”

Section: Introductionmentioning

confidence: 99%

Simulation of an Electrostatically Driven Microinjector

Krishnan

Daily

Nabity

2007

Journal of Propulsion and Power

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This paper presents results of analytical and numerical simulations of an electrostatically actuated microfuel injector. The electrostatic-structural coupling, efficiency of valves, and net flow rate of the pump are calculated using analytical relations and compared with numerical simulations. One way to increase flow rate is to increase the stroke volume, which may lead to large deflection of the diaphragm. Thus, the membrane load deflection relationship is no longer linear and when coupled to the inherently nonlinear fluid behavior leads to a complex problem. We used numerical methods to solve for the fluid-structure interaction and the large deflection of the membrane, and studied the effect of actuation frequency on the net flow rate.

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“…For the metallized gelled JP testing, the testbed was configured similarly to previous GRC JP detonation testing and similar to the configuration run at the Naval Postgraduate School (ref. 29). A bellmouth shaped head end mixer as well as a 12 in.…”

Section: Experimental Setup: Pulse Detonation Engine Test Hardwarementioning

confidence: 99%