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Pulsed Detonation Wave Engines

EXTROVERT Space Propulsion 16Papers on Pulsed Detonation Engines

Kailasnath, K., “A Review Of Research On Pulse Detonation Engines” http://reaflow.iwr.uni-heidelberg.de/~icders99/program/ms_pde/241.pdf

Karagozian, A. and team: Performance and Noise Characteristics of Pulse Detonation Engines, AIAA Paper

AIAA-2004-0469, 42nd AIAA Aerospace Sciences Meeting, January, 2004.

Numerical Simulation of Pulse Detonation Engine Phenomena, He, X. and Karagozian, A. R., Journal of Scientific Computing, Vol. 19, Nos. 1-3, pp.201-224, December, 2003.

Detonation Engine Simulations with Alternative Reaction Kinetics and Geometrical Features, He, X. and Karagozian, A. R., Paper 03F-70, Western States Section/The Combustion Institute Fall Meeting, UCLA, October, 2003.

Numerical Simulation of Pulse Detonation Engine Reactive Flow Processes, He, X. and Karagozian, A.R., Paper No. C-29, 3rd Joint Meeting of the U.S. Section of the Combustion Institute, March, 2003.

Reactive Flow Phenomena in Pulse Detonation Engines, He, X. and Karagozian, A. R., Paper no. AIAA-2003-1171, 41st AIAA Aerospace Sciences Meeting, January, 2003.

EXTROVERT Space Propulsion 16Papers, continued

Numerical Resolution of Pulsating Detonation Waves, Hwang, P., Fedkiw, R. P., Merriman, B., Aslam, T. D., Karagozian, A. R., and Osher, S. J., Combustion Theory and Modelling, Vol. 4, No. 3, pp. 217-240, September, 2000.

Mitrofanov V.V., Zhdan S.A., “Thrust Performance of an Ideal Pulse Detonation Engine”Combustion, Explosion, and Shock Waves July 2004, vol. 40, no. 4, pp. 380-385(6)

(Lavrent'ev Institute of Hydrodynamics, Siberian Division, Russian Academy of Sciences, Novosibirsk 630090;, Email: zhdan@hydro.nsc.ru )

“thrust performance of this engine for flight Mach numbers M [0; 3.6] and compression ratios p2/p1 [1; 80] are always higher than those of the ramjet and one-spool turbojet. As the compression ratio increases, the advantage of the pulse detonation engine becomes less noticeable.”

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http://www.isset.org/nasa/nano/www.grc.nasa.gov/WWW/AERO/base/pdet.htm

EXTROVERT Space Propulsion 16Features

“Pulse Detonation Engine Technology Project

- evaluate the application of pulse detonation combustion technology to hybrid subsonic and supersonic gas turbine engines for commercial and military applications and combined cycle propulsion systems for access to space applications.

- will be accomplished through the conceptual design of a number of possible system configurations followed by the "breadboard" demonstration of the critical sub-system(s) of the best candidate system(s).

High frequency (>60 Hz) pulse detonation combustors have been developed over the past 5 years by several commercial firms and government laboratories in configurations consistent with aerospace propulsion applications.

advantage over traditional near-constant pressure combustors in being more thermodynamically efficient by approximating constant volume (pressure gain) combustion.

Engine systems based on these combustors are expected to be significantly simpler than current engine designs due to reduced air and fuel inlet pressure requirements.”

http://www.isset.org/nasa/nano/www.grc.nasa.gov/WWW/AERO/base/pdet.htm

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“Three categories of Pulsed Detonation Engines:

1. "Pure" PDE's are the simplest systems consisting of an array of detonation tubes, an inlet, and a nozzle.

2. Combined-cycle PDE systems consist of a PDE combined with a ramjet/scramjet flowpath or other propulsion cycle where each cycle operates in a different speed range to optimize overall system performance.

3. Hybrid PDE's make use of detonative combustion in place of constant pressure combustion, usually in combination with turbomachinery.

For any of these systems, the requirements for the components external to the detonation tubes are not well understood. “

http://www.isset.org/nasa/nano/www.grc.nasa.gov/WWW/AERO/base/pdet.htm

EXTROVERT Space Propulsion 16“Hybrid pulse detonation systems are thermodynamically more efficient than standard gas turbine systems as well as being more light weight, thus reducing CO2 emissions. Pulse detonation also offers new solution space in which to pursue reduced NO emissions. Hybrid and combined cycle pulse detonation systems are expected to be efficiently operable to Mach numbers as high as 5 at a significantly lower cost than gas turbine engines due to simplified designs, lower part count, and reduced engineering material requirements. Potential for increased performance at reduced weight will provide additional vehicle weight fraction available for increasing health monitoring and more robust structural designs. Combination of pulse detonation cycles with other air-breathing and rocket cycles offers increased overall system performance at lower weight and cost for access to space applications. Mechanical simplicity of pulse detonation propulsion systems will enable shortened design cycle times. The system and cycle analysis tools being developed under this project will also aid in the design of new systems employing pulse detonation. Pulse detonation engines operate on a different thermodynamic cycle than conventional gas turbine engines, offering different operational modes and performance levels at various flight conditions. Mission-specific PDE designs could enable new aerospace missions, depending on requirements.”

EXTROVERT Space Propulsion 16http://planenews.com/modules.php?name=News&file=article&sid=2894

Engine may get first flight at base

“Air Force researchers hope to make the first flights of an airplane powered by a revolutionary jet engine here, they said Tuesday after demonstrating the airplane on a runway behind the Air Force Museum.Wright-Patterson became a candidate flight center after disappointing power tests in California prompted the research team to bring the airplane back here — where the engine was developed — for debugging. Now that it's here, the researchers are conducting "acoustic surveys" to find out if the so-called Pulsed Detonation Engine can be flown over the Wright-Patterson airfield without breaking federal noise rules, said Fred Schauer, the Air Force Research Laboratory engineer who led the development effort. …The engine put out a loud buzz that sounded like cloth being ripped as it pushed a sleek, white airplane a short distance down the runway. Test pilot Michael Melville cut the engine after a few seconds, but the sound continued to echo from surrounding buildings — soon joined by the engineers' applause. "It's a very sharp, loud noise" inside the cockpit, said Melville, who gained fame in June for piloting the privately financed SpaceShipOne rocket into space. Schauer said the sound can carry as far as 8 miles directly behind the engine's four exhaust pipes. Up close, the PDE is an ungainly mass of tubes, wires and belts stuffed into the sleek, white frame of a Long-EZ, a fiberglass airplane designed for amateur aircraft builders. The engine protrudes from the belly of the frame. “

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“A collection of off-the-shelf parts, it uses a Pontiac Quad-4 engine head to valve fuel and air into the pipes, where ordinary spark plugs ignite the mixture.

But once that happens, "We do a few tricks" to turn the ordinary combustion into a high-pressure detonation, Schauer said.

The result is an extremely energetic exhaust thrust. The ripping sound comes from the fact that each pipe is detonating 20 times per second — 80 times per second in all.

Schauer's development team tested the first PDE engines at the Propulsion Directorate on base. A local aerospace company, ISSI, built three demonstration engines. Mojave, Calif.-based Scaled Composites LLC — the same company that designed and built SpaceShipOne — integrated the engine into the airplane, which it owns. “

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“.. two engines tested at Wright-Patterson put out 150 pounds of thrust, but this one only produced about 100 pounds in six months of taxi tests at Mojave.

"We brought it back to Dayton to find out why," he said. “

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http://www.mdatechnology.net/techsearch.asp?articleid=479Small Vector Thrust Pulsed Detonation Rocket Engine Enigmatics, Inc. (Washington, DC)

Summary: With the help of BMDO SBIR funding, Enigmatics, Inc. (Washington, DC), is developing a very small (less than ½ inch), very efficient propulsion engine called a pulsed detonation engine (PDE). For BMDO, this technology is targeted for use as a divert engine in a midcourse multiple kill vehicle. Nano-sized satellites and unmanned aerial vehicles are two more near-term applications of the PDE, while large-scale spacecraft and aircraft could eventually benefit from the technology since it is scalable to larger sizes. Enigmatics has partnered with Science Applications International Corporation, a Fortune 500 company, to develop this technology.

“…more efficient and flexible than today's propulsion technologies—and will be small enough for nano-sized satellites. “

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“PDE works by detonating fuel in pulses, allowing it to run a more efficient thermodynamic cycle than a conventional rocket, one in which the chamber walls absorb less heat. Although this process, called constant-volume combustion, is inherently more efficient than the constant-pressure process used by conventional rocketry (gas turbine and jet propulsion engines used the constant-pressure process during the first half of the 20th century), it has traditionally had a very slow explosion cycle reaction rate, which limited these engines to very small output thrusts. With intermittent detonation, though, the reaction rate has improved, as a detonation wave travels about two orders of magnitude faster than a typical deflagration wave. As a result, Engimatics has been able to achieve pulse detonation rates of 250 detonations per second in recent tests, with a capability of reaching 500 per second.”

“.. no moving parts and can be built from conventional materials using standard manufacturing methods, a PDE can be amenable to low-cost fabrication.”

EXTROVERT Space Propulsion 16“The race heats up to replace the jet turbine with a more efficient source of Mach-breaking airpower: the pulse-detonation engine”. by Jim Kelly

http://www.popsci.com/popsci/aviation/article/0,12543,473272,00.html

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“The combustors detonate alternately—when one is firing, the others are not. But this cycle occurs 80 times per second, and our photographer shot the image using a 1/15-second exposure. The result: Each of the tubes fired several times during the exposure, so all five appear to be lit at once. Photograph by John B. Carnett”

EXTROVERT Space Propulsion 16 http://std.msfc.nasa.gov/sciresearch/adv_chem_prop.html

“Combined-cycle, pulsed-detonation engine researchPotential application in both Earth-to-orbit and in-space transportation… doesn't necessarily require turbopumps for operation since reactants are injected into the combustion chamber (tube) at low pressure (one atmosphere). Higher T/W. Rocket-based ISP (specific impulse) ~ 200 seconds for hydrogen and 120 seconds for most hydrocarbons. Isp as high as 600 seconds possible for air-breathing modes of the pulsed detonation engine. Research Goal: demonstrate autonomous engine operation under varying air availability. Closed loop control is implemented on a pulse-by-pulse basis. Motorcycle and automotive technology allow higher cyclic rates with available technology and hardware. Liquid and gaseous hydrocarbons and gaseous hydrogen (GH2) are used as fuels with air and gaseous oxygen (GO2) as oxidizers.

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“At this particular moment, the game of catch-up involves an almost intolerable amount of noise. The sound of a hydrogen-air mixture detonating 40 times a second in a 3-foot-long, 2-inch-diameter metal tube is a cross between a cruise-ship horn and a jackhammer. It seems to go right through your skull, even from behind the concrete and double-pane tempered glass of the control room. The noise stops after a seemingly endless five or six seconds, as the tube slides back along the thrust stand to its resting position; the roar of the compressors that feed the test cell is almost soothing in comparison. "At a little bit lower frequency, we've run it for an hour straight," Tony Dean, the head of GE's pulse-detonation research effort, says proudly.”

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MilestonesGE: 1-A: First U.S. jet engine (1941); J93: First Mach 3 engine (1957); GE90-115B: World record for single-engine thrust: 127,900 lb. (2003)P&W: J57: Powered first supersonic production aircraft, the F-100 Sabre fighter (1953); PW2000: First engine to use digital controls for maximum fuel efficiency (1984); F119-PW-100: Allowed supersonic cruise without afterburner, in F-22 Raptor (1997)

PDE StatusGE: Bench-scale experiments ($8 million invested since 1999)P&W: Full-scale multi-chamber test engine ($20 million invested since 1993)

Tech StrategyGE: Aerodynamic valve prevents airflow to the chamber at the appropriate time, permitting detonation.P&W: High-speed rotary valve cuts off airflow to each of five combustion chambers; a pre-detonator initiates the transition.

Short-term goalsGE: Hybrid PDE prototype by 2005P&W: Pure PDE missile prototype by 2005

EXTROVERT Space Propulsion 16Typical PDE engine

http://www.seas.ucla.edu/combustion/projects/pulsed_detonation_wave.html

Prof. Ann Karagozian, UCLA

EXTROVERT Space Propulsion 16Theory

Kailasnath, K., “A Review Of Research On Pulse Detonation Engines” http://reaflow.iwr.uni-heidelberg.de/~icders99/program/ms_pde/241.pdf

• Key feature: Very rapid material and energy conversion.

• “Burning” or material conversion rate, typically tens of thousands of times faster than in a flame.

• Advantages for propulsion: compact and efficient systems.

• Not enough time for pressure equilibration - overall process is thermodynamically closer to a constant volume process than the constant pressure process typical of conventional propulsion systems.

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Consider 3 cycles with same amount of heat release: Efficiencies are:

1. Constant pressure 27%

2. Constant Volume 47%

3. Detonation 49%

http://reaflow.iwr.uni-heidelberg.de/~icders99/program/ms_pde/241.pdf

Decrease in specific volume (increase in density) and increase in pressure comparedto constant-volume process.

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Nicholls:

Hydrogen-air mixture in a detonation tube, open at one end with co-annular fuel and oxidizer injection at closed end. Spark plug 10 inches from closed end.35Hz frequency: Specific Impulse 2100 seconds. Questionable whether detonation or deflagration.

Cambier & Adelman, 1988: 50 cm long tube, 43-cm long diverging nozzle. 667Hz. Isp ~ 6500 sThrust predicted to scale linearly with detonation chamber volume and operating frequency.

Issues: Self-aspirating engine? Deflagration-to-detonation transition distance may be too large for practical use.“Schelkin spiral” to reduce DDT distance by factor of 2 to 4 over a range of equivalence ratios.Rotary valve design to fill some chambers while others are detonating. Mixing of fuel and oxidizer: turbulence helps, but reduces thrust due to losses.Raising initial pressure is beneficial.Failure modes: DDT transition failure; premature ignition.

EXTROVERT Space Propulsion 16Karagozian, A.R., He, X., “Numerical Simulation of Pulse Detonation Engine Phenomena”. J. Scientific Computing, Vol 19, No.3, Dec. 2003

Process: 1.Combustible mixture in tube. 2. Deflagration transitions to detonation, moves to open end. 3. Expansion wave moves upstream. Reflects as expansion: pressure drops below outside: fuel+ oxidizer flow in. 4. Expansion reflects as shock from open end. 5. Shock reflects from thrust wall, imparting thrust; transitions to detonation

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Impulse is defined as,

0

( )wI A p t dt

Specific Impulse

spIIVg

Fuel Specific Impulse

,sp

sp ff

II

Y

fYwhere Is the fuel mass fraction within the initial premixed reactants in the tube.

Tds de pdV

Entropy Increase:

Constant volume: dV = 0

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“Combined schlieren and PLIF image of propagating detonation in 20 kPa 2H2+O2+17Ar. Direct experimental observations of the reaction zone structure in propagating detonations have been made using planar laser induced fluorescence (PLIF) of the OH radical. For the first time, images were obtained with sufficient spatial resolution to resolve 'keystone' features in the reaction front due to variations in the lead shock

strength.” http://www.galcit.caltech.edu/EDL/projects/pde/pde.htmlFlorian Pintgen and Jo Austin

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Shadowgraph of critical detonation diffraction in 100 kPa 2H2+O2. The re-initiated detonation is propagating spherically outward and sweeping back into the shocked reactants.Eric Schultz http://www.galcit.caltech.edu/EDL/pro

jects/pde/pde.html

Numerical density contours of detonation emerging from tube. UCLA Courtesy Prof. Ann Karagozian

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“In June 2008, the Defense Advanced Research Projects Agency (DARPA) unveiled Blackswift which was intended to use this technology to reach speeds of up to Mach 6.However the project was cancelled soon afterwards, in October 2008.”

From “Wikipedia”: http://en.wikipedia.org/wiki/Pulse_detonation_engine

From “Wired” magazine:

“Blackswift Swoops in for $750 million

http://blog.wired.com/defense/2008/01/blackswift-swoo.html

By Sharon Weinberger January 24, 2008 |

The Pentagon's 2009 budget request -- expected to go to Congress next month -- will ask for $750 million to fund a prototype hypersonic aircraft called Blackswift, reports Inside Defense. The Blackswift project, will will initially be managed by Defense Advanced Research Projects Agency (DARPA), also includes participation from the U.S. Air Force. DARPA and the Air Force signed a memorandum of understanding on Blackswift last year..”