Talk:Pulse detonation engine

Let's get some pictures in here

There's a great deal of information on this subject, somewhere. I don't know enough to make the necessary changes, but yeah this needs some pictures, and an organizational cleanup wouldn't hurt. - SloverA 12:34, 2 November 2005 (UTC)

This page needs serious wiki-fying, and it was subject to Digging today. 70.35.222.158 01:34, 4 May 2006 (UTC)

Dan Brown

This type of propulsion is also discussed in Dan Brown's novel 'Deception Point'. The air craft in question is an Aurora model.

Dan Brown is incapable of describing well-documented technology accurately, so it's completely mad to give him any sort of credence when it comes to experimental or hypothetical technology. His statement that "all technology desribed in this novel exists" should be considered as part of the novel - i.e. just as fictional as the rest of it.

Needs sources

I'm pretty sure that the text is overstating the efficiency win of PDE's. I did once see a list of specific impulses that were thought to be achieveable with PDE, and they weren't that good in quite a lot of cases, but I don't have a reference handy.

In any case, there's no citations at all. That's bad.WolfKeeper 16:59, 3 September 2006 (UTC)

The NASA website is error 404. I think its been removed. I'll take out the link, feel free to reverse it if I'm wrong.

Yes. The efficiency of PDE is greatly overestimated. People are missing that the system efficiency and overall efficiency consist of many factors.

There are burn efficiency (how much fuel burns well), fuel energy density (oxidizer drops it), thermodynamic efficiency (how much heat turns into pressure), propulsive efficiency (how close to perfect is the exhaust velocity), plus engine drag and specific thrust. These are independent components of any propulsive system efficiency, which are balanced in its design.

Layering of these efficiencies produces, in the end, the overall efficiency and then less well defined system efficiency (accounting for drag and weight of the engine). There are no "more efficient" or "less efficient" engines, the key parameters produce different results for any application, i.e. depending on airspeed, altitude and the aircraft, different engines become most efficient. Even different parameters can have radically different influence, i.e. higher specific impulse (of the exhaust) gives nearly linear increase in the efficiency of a rocket, but a decrease in the efficiency of a turbofan. Though turbofans now more commonly use fuel specific impulse, which is determines in regards to fuel alone rather than the entire volume of accelerated air.

PDE have better burn efficiency than any other engine, but that's it. Unlike turbofans, they don't accelerate bypass air, just what is used for the detonation, which leads to very limited working mass. As a result, such engine produces a lot of energy', but most of that energy is not converted into thrust.

For instance, accelerating 2,000m^3 of air in a high-bypass turbofan to 100m/s produces the same thrust as accelerating 200m^3 to 1,000m/s in a non-bypass engine, i.e. PDE, yet requires 10 times less energy.

PDE can compete (likely with advantage) and should be compared with ramjets in efficiency, but not turbofans.

Of course, at high Mach numbers, where turbofans are simply impossible or impractical, PDE enter the actual competition, with ramjets, scramjets, ramrockets, LACE, et cetera. There it is to be seen whether high weight of the engine (to survive detonation forces) will be compensated by better burn efficiency. CP/M ^comm |Wikipedia Neutrality Project| 16:39, 7 January 2008 (UTC)

Here are some references that I have not looked over but may have some use. I'll see if I can get a picture for the article some time soon.

• Yungster, S. and Perkins, H.D., “Multiple-Cycle Simulation of Pulse Detonation Engine Ejector,” AIAA 2002-3630, October 2002.
• Kailasanath, K., “Recent Developments in the Research on Pulse Detonation Engines,” AIAA Journal, Vol. 41, No. 2, 2003, pp. 145-159.
• Bussing, T. and Pappas, G., “An Introduction to Pulse Detonation Engines,” AIAA 94-0263, January 1994.
• Takuma, E. and Fujiwara, T., “A Simplified Analysis on a Pulse Detonation Engine Model,” Trans. Japan Soc. Aero. Space Sci. Vol. 44, No. 146, 2002.
• Hekiri, Haider, "Parametric Cycle Analysis for Pulse Detonation Engines," Master's Thesis, Department of Mechanical and Aerospace Engineering, The University of Texas at Arlington, Arlington, TX, 2005.
• Panicker, P.K., Wilson, D.R., and Lu, F.K., "Operational Issues Affecting the Practical Implemenatation of Pulse Detonation Engines," AIAA-2006-7959, 14th AIAA/AHI Space Planes and Hypersonic Systems and Technologies Conference, Nov. 6-9, 2006, Canberra, Australia.

EMBaero (talk) 18:11, 7 January 2008 (UTC)EMBaero

The efficiency of a detonation engine is far greater than that produced by the simple deflagration of fuel thus the specific impulse of the engine tends to be greater tat that produced by ram/turbo jet. I belive this is made clearin the article. Neucleon

I've explained that above. The burn efficiency is greater, i.e. less fuel is left unburned. Not "far" greater, since normal turbine already has great burn efficiency, but PDE does produce more heat. However, PDE doesn't utilize that heat as well as a turbofan does. CP/M ^comm |Wikipedia Neutrality Project| 12:09, 2 May 2008 (UTC)

First flight

FWIW, the first flight of the Rutan/AFRL PDE Longeze took place at Mojave Airport today. 71.108.80.39 (talk) 03:36, 1 February 2008 (UTC)

I've been able to confirm from another source that this is all correct. Pictures and videos will be released soon. EMBaero (talk) 16:16, 6 February 2008 (UTC)EMBaero

Not so - the German WWII V1 Buzz bomb used a PDE and was in mass production. (Source - Wikipedia "V-1 flying bomb") 220.253.14.201 (talk) 00:06, 17 February 2023 (UTC)

Uh, no. The V-1 had a pulsejet engine, per the reliable sources in that article. A PDE is an entirely different thing. BilCat (talk) 06:35, 17 February 2023 (UTC)

Continuous Detonation Engine

Could someone perhaps add data about US Patent 3336754, which is the Continuous Detonation Engine? It's mentioned as a possible future solution in VULCAN development, as seen in DARPA conference papers, page 29:

http://www.darpa.mil/TTO/solicit/BAA08-53/VULCAN_Industry_Day_Presentations.pdf

The term itself is not used anywhere on Wikipedia, although it is relevant both here and to the Rocket engine article, as some of the designs, depending on the purpose, either store fuel and oxidant, or use atmospheric air with only fuel stored.

There is little free information on the subject, most is contained in scientific publications that have to be purchased, for instance:

http://pdf.aiaa.org/preview/CDReadyMISPHST08_1877/PV2008_2680.pdf

The article mentions a rocket-like hydrogen-oxygen reaction, but from what I've gathered, a naturally aspirated CDE could be used at high mach speeds.

Someone with an extensive university library access could perhaps run a search. --Ssabot25 (talk) 14:01, 1 July 2008 (UTC)

There is a video of a working prototype of a Rotating continuous detonation wave engine; should that me mentioned in this article? http://www.youtube.com/watch?v=QbJgOk2rDbI —Preceding unsigned comment added by 76.185.57.136 (talk) 19:29, 19 February 2010 (UTC)

De Laval nozzle to initiate DDT?

It seems like it would make sense to use a De Laval nozzle to help initiate the deflagration to detonation transition with fuel injection on both sides of the pinch. Does it? —Preceding unsigned comment added by 70.15.42.72 (talk) 01:34, 3 April 2010 (UTC)

Not Blackswift

I removed this: "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 afterward, in October 2008. " Because Blackswift was designed to be a scramjet. 66.127.52.57 (talk) 06:27, 14 June 2010 (UTC)

References

Not credible

I don't see any references to credible sources that suggest 'serious' interest in this technology by serious technology developers. This suggests that there isn't any such interests, which suggests that the article grossly oversells the idea. Citing Fox News, Popular Science, a 1952 patent, and video demonstrations of stuff is below Wikipedia standards. The DARPA reference is the best, but doesn't the hype.66.127.52.57 (talk) 06:48, 14 June 2010 (UTC)

This is a ridiculous comment. There has been over 50 years of research on this engine, resulting in large amounts of literature and probably hundreds of millions of dollars invested by top companies and the government.EMBaero (talk) 12:10, 14 June 2010 (UTC)

The 'Pulse detonation wave engine' section

Google search for

"pulse detonation wave engine" OR "pulsed detonation wave engine" -wikipedia

(the minus sign means "exclude") found "about 5,150" results. So this is a significant topic that people may want information about, whether pulse detonation wave engines exist in the real world or not. Anthony Appleyard (talk) 05:18, 11 August 2010 (UTC)

Doesn't matter, as it clearly fails WP:Reliable sources. As an admin, you should be well aware of this. Ng.j (talk) 07:36, 18 April 2011 (UTC)

Whatever Pulse Detonation Technology powered the delta wing aircraft witnessed on December 18, 1999 at 5:00 PM MST, high over Prescott, Arizona on its way west (probably to California) is not known. This flight was most likely not the first flight either, but predates the officially released PDE First Flight storyline (above) by almost a decade. Flakship —Preceding undated comment added 06:50, 11 June 2012 (UTC) See review of cover story article in Aviation Week & Space Technology March 5, 2006 for delta wing configuration. Flakship 07:00, 11 June 2012

In popular culture

Another example - Grigory Adamov's sci-fi novel "Mystery of two oceans" (1938), but there was soviet submarine with pulse detonation engine.Ходок (talk) 09:57, 4 January 2011 (UTC)

Speed regime

The article states: "Theoretically, a PDE can operate from subsonic up to a hypersonic flight speed of roughly Mach 5."

This claim should be backed up by a source and an explanation needs to be added. Turbojets are limited in speed because the airflow over the fan blades must remain subsonic. Ramjets have a lower bound because they compress air by forward motion and an upper bound because the combustion must be subsonic. Scramjets have a lower bound because like ramjets they compress air by forward motion, but since the combustion takes place at supersonic speeds the lower bound is even higher and there's no theoretical upper bound (barring limitations by temperature and material strength).

These limitations are explained in the respective articles. But this articles lacks an equivalent explanation. The theoretical/physical causes for lower and upper bound need to be included. 77.186.11.245 (talk) 11:14, 10 October 2013 (UTC)

Actually, a little thought should allow you answer these questions yourself. A PDE doesn't have fan blades, so isn't limited in max speed by supersonic blade speeds like a turbojet. A PDE doesn't require airflow to compress incoming air, so isn't restricted by a min speed like a ram or scramjet. Having worked as a combustion engineer on all three systems at different times over the past 30+ years, I can tell you a PDE can indeed operate at zero speed up to hypersonic speeds. — Preceding unsigned comment added by 68.50.90.64 (talk) 00:28, 24 September 2016 (UTC)

Really?

This article states: "The basic operation of the PDE is similar to that of the pulse jet engine. In the pulse jet, air is mixed with fuel to create a flammable mixture that is then ignited in an open chamber. The resulting combustion greatly increases the pressure of the mixture to approximately 100 atmospheres (10 MPa),[5] which then expands through a nozzle for thrust." This appears to be saying a pulse jet can achieve pressure ratios on the order of 100:1 - no way. At most, a pulse jet can get maybe 2:1 - that's why you don't see them anymore, very very inefficient. Now, a PDE can achieve the 100:1 ratio, but it does that by creating a detonation wave - hence, the name. Combustion in a pulse jet is simple deflagration - no way can it boost pressure up to 100 atm. — Preceding unsigned comment added by 68.50.90.64 (talk) 22:50, 23 September 2016 (UTC)

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