Chemical Pulse detonation engines

Pulse detonation engines (PDE) can achieve a maximum of 50% efficiency verus 30% for conventional jet engines Pratt & Whitney and General Electric now have active PDE research programs in an attempt to commercialize the designs with high pulse rates of 50-100 times per second to allow for less vibration. Some of the top scientists and engineers in the field say that with the right economic incentives and a few well-placed technology leaps, they could get to a flight-ready system in five years. (Air and Space magazine sept 2007). They are 3 to 4 on the technology readiness scale (working in the lab).

Pulse-detonation engines could push aviation into a new age, leading to superefficient subsonic jetliners, cheaper suborbital flight and more affordable space access.

There is a lengthy article at Air and Space Magazine on pulse detonation

The pace of current research and development points the way to three phases of pulse detonation engine technology, each a bit more complex than the one preceding it.

The first phase could be called the “pure PDE”: Essentially it focuses on developing the detonation tube, which would power a very-high-speed, air-breathing missile. In this application, engineers and scientists can punt on two of the biggest technology problems—life, or the durability of the system, and noise. The missile has to fly only once, so long life for the metals or components is not a concern. And at the high speeds—around Mach 6—and altitudes in which the missile would operate, less noise is also moot. This is the area in which Adroit Systems, and later Pratt & Whitney, made the most strides. It was their machine that would have been flown on NASA’s F-15B.

The next phase could involve using pulse detonation engines to address another pressing issue in combustion: afterburners for fighter aircraft. Today’s fighter engines simply spray aerosolized fuel into a long tube aft of the turbine section, literally dumping extra fuel-air mixture into the hot gas stream for a brief extra kick of speed. Engineers think that if they add pulse detonation technology to a low-bypass-ratio turbine engine—the modern fighter jet engine—they can get the efficiency benefit of pressurized, shockwave combustion. It’s relatively simple because the pulse detonation tube would be at the end of the engine and not in the middle of the turbo-machinery. Here again, life and noise are less of an issue than they might be in a commercial aircraft. Fighter pilots only fly on afterburner about five percent of the time, and anyone who has seen an airshow knows fighter jocks usually don’t worry about making a racket.

The third phase is where it gets most complicated, but is the one that may offer the biggest payoff: pulse detonation in the middle of the engine. Having a compressor upstream and a turbine downstream, says GE’s Dean, is a potential high-value payoff that keeps his company attracted to PDE development. A PDE-based combustor is one of the main areas of work for a young researcher on Dean’s team named Adam Rasheed. Rasheed is chronicling his work on a publicly available blog, “From Edison’s Desk” (www.grcblog.com). The publicity seems to have done him some good: The Massachusetts Institute of Technology’s Technology Review magazine in 2005 named Rasheed one of under the age of 35.

Like everyone else, Rasheed has his eyes on a jet engine that burns five percent less fuel—an enormous leap compared with today’s fuel-saving techniques. In a world in which efficiency improvements of even 0.2 percent are considered a major breakthrough, “PDEs represent a possible game-changing technology that could revolutionize aerospace propulsion,” Rasheed writes. Even a one percent improvement would save hundreds of millions of dollars in fuel.the world’s top 35 researchers

FURTHER READING
29 page overview of pulse detonation engine technology written in 2004

Nuclear pulse rocket engines, which can go up to 10% of lightspeed primarily using technology that we have had for decades.

2 thoughts on “Chemical Pulse detonation engines”

  1. Jamais

    I appreciate you taking the time to write your comment.

    I agree that Nuclear safety and anti-proliferation should be improved. Nuclear safety is far better than coal safety. Coal under normal operation kills thousands.

    Proliferation is not something that I am as concerned about because I do not see the incremental risks from this point being that bad. 40 countries already have the nuclear materials for bombs. I see more concern over lost and stolen material and knowledge from the old Soviet weapons.

    I think the comparison of centralized or decentralized and safety needs to be made in the context of what is actually getting built. 50% of the electrical power in the USA is coal. 85% of it in China is coal.
    If new power is being built that is coal, then my preference is that nuclear be built instead. If people can get wind or other renewables up instead then that would be good as well.

    Changing cars and community layouts are multi-decade efforts. 500 million cars now. 70 million new cars per year. less than 1 million hybrids. Again I support the efforts for more sustainable communities and better efficiency for cars. I would also support giving away or making freely available mass produced folding electric bikes to enhance public transit. (an enhanced Netherlands type system)

    I would like more immediate actions (which means start now and ramp up as quickly as possible over 10-20 years) to stop the death and pollution from coal and to mass produce power and ramp up efficiency to reduce the need for coal and oil. The 1 million dead per year from coal is Holocaust level numbers and people are too blase about the action to stop it and the lets get it exactly right with solar and wind and biomass and efficiency is too slow. the 27,000 dead per year in the USA is 25 times the US Iraq war casualties. If we massed produced nuclear then we could get off of oil and the middle east becomes like Africa. A non-strategic death zone.

    If we could force coal to get cleaner and less deadly and I understand that 90% of US deaths could be mitigated with the best coal systems and processes and probably 96% of China’s deaths
    then I would like to see that. In the absence of progress there I support nuclear.

    I am also less concerned about nuclear war and thus proliferation. The US still has thousands of weapons. Any country that tries to use just 1 or 2 will be bombed flat. I think the bombing flat can be done conventioanlly. Rolling thunder from Vietnam (1000 times the bombs of firebombing tokyo) + Firebombing of Tokyo (100,000 dead) to the transgressor.

    20th century 200 million killed conventionally.
    200,000 killed with nukes.
    People should be less fixated on nuke weapons and ignoring that it is deaths from war and deaths in general that they should fear and which we should plan on stopping.

    the small scale and distributed improvements are great, but the macro centralized stuff still has massive impact.

    Reply
  2. Brian,

    I’d be more inclined to support the expansion of nuclear power if the French were put in charge of it.

    There are two commonly-recognized problems with nuclear power as it’s currently produced, and one subtle problem.

    * To the degree that small-state nuclear weapons proliferation is a problem, expansion of uranium enrichment capabilities means expanding the potential for nuclear weapons development. (Even though power only requires low enrichment and bombs need high enrichment, the tools to do the uranium processing are the same.) It would also increase the potential for “lost” or stolen nuclear materials.

    * In the US in particular, and (as far as I can tell) to a degree globally, the nuclear power industry has been woefully irresponsible when it comes to safety, security and cost management. This industry has not demonstrated any real indication of learning lessons not forced upon them by legislation and activism.

    * The more subtle concern is that nuclear power, as it’s currently done, is a highly-centralized method of energy production. The real innovation (both in technology and utility management) is coming in distributed energy production. Think massive time-sharing mainframe vs. myriad PCs.

    -=-=-=-

    With regards to environmentalist claims that shivering in the dark and walking uphill both ways in the snow should be mandatory, it’s true that there are still some unreconstructed greens still living in the hippy mentality of 1973. But serious enviros these days are much more aware of both technology and human behavior, so be sure that your perception of what they say isn’t itself rooted in 1970s environmentalism. I don’t know anything about the European guys you mention, so I won’t comment on them. But:

    * Using less power doesn’t necessarily mean going without services. Efficiency is the mantra. According to Art Rosenfeld of the California Energy Commission and Lawrence Berkeley Labs, we’ve seen an average improvement in use efficiency of 1% per year over the last century, but in times of high energy prices (and in California in general), that improvement can be 2% up to 5%.

    An average improvement in energy efficiency of just 3% per year, globally, would allow in the year 2100 for 10 billion people living at European standards of living on less total global energy than we use today.

    As for making people give up cars, the real innovation in that is moving upstream — not simply focusing on individual behavior, but looking at how urban design forces behavior. Change the design of communities so that car use is less desirable than other options, and you’ll reduce the amount of driving — without making people feel like they’ve lost something.

    I know I’ve gone on for too long here, but this is something I wrote about for just about every day from late 2003 to early 2006, over at WorldChanging. There’s tons more information about all of that over at the site.

    Reply
  3. You dumped this post on my site twice. I will let it go and post my reply twice.

    As noted in the information provided at Gerry’s links, the costs of concentrated solar power have been and still are much higher, but are “expected to tumble”.
    The california CSP
    http://en.wikipedia.org/wiki/Deployment_of_solar_power_to_energy_grids
    is 354 MW and is 90% of the commercial installations up to this point. That is 1000 times less than installed nuclear capacity. There are new deployments coming but they are in total maybe 2 GW over the next 10-15 years.
    I wish this technology the best of luck but until it is helped to stop the production of new coal plants then I would rather see more nuclear power instead of new coal power. Get renewables of all kinds up to a global level of 200-400 GW per year of new capacity. For Europe it needs to be at about 40GW per year of whatever “clean electrical energy” to meet new demand. If it new renewable capacity was at 80GW per year then it could start to replace european coal usage over 20 years then it could start replacing nuclear. The proposed buildout of CSP over 40 years is less than 3 years of European demand growth.

    The system that you are talking about for europe looks like 100GW by 2050 using 400 billion euros over 30 years. If it was funded which it has not been.
    http://en.wikipedia.org/wiki/Trans-Mediterranean_Renewable_Energy_Cooperation

    The EU gets 13% of its power and a large fraction of its electricity from coal. 14% from nuclear.
    http://www.eia.doe.gov/oiaf/ieo/pdf/coal.pdf
    Coal use in europe is projected to modestly increase in the case where current nuclear power stays in place.
    http://www.eia.doe.gov/emeu/cabs/European_Union/Full.html

    Electricity demand is projected to grow in europe by 52% by 2030 needing 761GW more capacity. Current plans is for 80% of that to come from gas. But Europe is planning to keep all of its coal power capacity and increase it by 5%
    Even this most optimistic of alternative energy proposed scenario does not meet the increase demand with alternatives like wind.
    http://www.ewea.org/fileadmin/ewea_documents/documents/publications/briefings/no_fuel_lo_res_72dpi.pdf
    .

    Blah blah projection could provide nearly 7,000 GW of capacity. And if I made a Dyson shell of solar collectors around the sun I get a billions of times the energy that we use. When does it happen? how much does it cost? who is seriously considering building it. Vinod Khosla has got a lot of money and political connections. He and others can prove CSP out and make 100GW of it and we can start seriously looking at it.

    Reply
  4. Regarding “Climate, pollution, nuclear” (2007-02-18), there is absolutely no need for nuclear power in the US because there is a simple mature technology that can deliver huge amounts of clean energy without any of the headaches of nuclear power.

    I refer to ‘concentrating solar power’ (CSP), the technique of concentrating sunlight using mirrors to create heat, and then using the heat to raise steam and drive turbines and generators, just like a conventional power station. It is possible to store solar heat in melted salts so that electricity generation may continue through the night or on cloudy days. This technology has been generating electricity successfully in California since 1985 and half a million Californians currently get their electricity from this source. CSP plants are now being planned or built in many parts of the world.

    CSP works best in hot deserts and, of course, these are not always nearby! But it is feasible and economic to transmit solar electricity over very long distances using highly-efficient ‘HVDC’ transmission lines. With transmission losses at about 3% per 1000 km, solar electricity may be transmitted to anywhere in the US and Canada too. A recent report from the American Solar Energy Society says that CSP plants in the south western states of the US “could provide nearly 7,000 GW of capacity, or ***about seven times the current total US electric capacity***” (emphasis added).

    In the ‘TRANS-CSP’ report commissioned by the German government, it is estimated that CSP electricity, imported from North Africa and the Middle East, could become one of the cheapest sources of electricity in Europe, including the cost of transmission. A large-scale HVDC transmission grid has also been proposed by Airtricity as a means of optimising the use of wind power throughout Europe.

    Further information about CSP may be found at http://www.trec-uk.org.uk and http://www.trecers.net . Copies of the TRANS-CSP report may be downloaded from http://www.trec-uk.org.uk/reports.htm . The many problems associated with nuclear power are summarised at http://www.mng.org.uk/green_house/no_nukes.htm .

    Reply

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