Author Topic: New principle of combustion offers potential to double efficiency of Engines  (Read 9631 times)

Online Stormbringer

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http://www.sciencedaily.com/releases/2013/11/131127125824.htm

the article mentions aerospace applications. now i am not sure if this directly translates to rockets but it could and also it would have an effect on hybrid vehicles that use both conventional aviation engines and rockets or RAM SCRAM jets.

i think it means either less massive engines with the same power or the same mass as present engines but more power or some combination of the above.

what do you think?
« Last Edit: 11/27/2013 09:05 PM by Stormbringer »
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Offline Danderman

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It's probably academic.

Offline IRobot

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Unsure if it applies to rockets but modern diesel engines are already working at similar efficiency. Might be a breakthrough in America but in Europe half the cars are diesel.

Offline Pete

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Double the efficiency of (internal combustion) engines?

Take a nice big marine diesel, double its efficiency, and you have the key component of a perpetual++ motion machine. Double it's 56% efficiency would be...impressive.

Even a basic luxury mercedes diesel manages engine efficiency of 41%

The science the article is based on is sound enough, but I bet the researchers cringed when reading the misquotes and hyperbole in that article.

Online Stormbringer

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And the german diesels are whisper quiet, too. in America you know a diesel is coming from a mile away and the cabin ride is not very good either. You guys do know how to do a diesel.

Unsure if it applies to rockets but modern diesel engines are already working at similar efficiency. Might be a breakthrough in America but in Europe half the cars are diesel.
« Last Edit: 11/27/2013 10:28 PM by Stormbringer »
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Offline Roy_H

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The article is almost all hype, and very few facts. The facts presented are all well known, and much research and development is going on in this direction by most auto companies. They claim up to 60% efficiency, and as Pete pointed out there are already advanced diesels at 56% efficiency. Not applicable to rockets.
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Offline clegg78

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I have a Touareg TDI, and seeing a 5000lb SUV get 30Mpg at times on the highway should be some indication of just how efficient the germans (and the top tier of Diesel ICE engineering) has come.   Just look at what Audi is doing with their R&D from race programs:  https://www.audi-mediaservices.com/publish/ms/content/en/public/pressemitteilungen/2013/06/13/audi_at_le_mans__engine.html
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Offline Danderman

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so there are no diesel fueled rockets because ....................... ?

Offline kch

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so there are no diesel fueled rockets because ....................... ?

As I recall, there are different grades & formulations of kerosene-type liquids for heating, oil lamps, internal combustion engines (diesel fuel), jet engines (JP-x), rocket engines (RP-1), musical instruments (valve and key oil), and probably others.  I'd be tempted to call the Atlas-family rockets "diesel fueled" ... wouldn't be literally correct, but not that far off.

Offline ChrisWilson68

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so there are no diesel fueled rockets because ....................... ?

First and foremost, the term "diesel" refers to a type of piston engine.  In a diesel engine, on every stroke the compression energy is what ignites combustion, as opposed to a spark plug.

Diesel fuel is fuel optimized for a diesel engine.

Rocket engines aren't remotely like diesel engines.  Combustion is continuous in a rocket engine.  There's no need for ignition on each stroke, or even the concept of a stroke.

Since rocket engines are very different from diesel engines, it would be silly to try to use diesel fuel in a rocket engine.

The thermal efficiency of a diesel engine versus a gasoline engine with a spark plug isn't simply because it uses diesel fuel, and pouring diesel fuel into a rocket isn't going to give you a gain.

Offline ChrisWilson68

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The technology the article is referring to is a different type of piston engine.  It has almost zero relevance to rocketry or spaceflight in general.

I say almost zero instead of zero because XCOR has been working on a rocket engine for spaceflight applications that uses a piston pump instead of a turbo pump to pump the fuel into the rocket engine. So, in theory, this new technology could make a more efficient fuel pump.  Still, that's at best only going to have a very marginal effect on the rocket's performance.

At the bottom of the article, it says the source for the article is the research group claiming the breakthrough.  I haven't seen any independent analysis of this by anyone else, and virtually nothing else in the media has mentioned this.  So, nobody seems to be taking these claims of a breakthrough seriously.

And the article doesn't have enough details for anyone to independently verify any of it.

Offline Lee Jay

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A Diesel is efficient because of its high compression ratio and thus its high peak cylinder pressure and temperature.  The downside of that is enormous production of oxides of Nitrogen, which have to be dealt with if the car is to be even remotely clean.  Mercedes sprays a urea solution into the exhaust for this purpose, at substantial expense.

I'd guess the closest analog in rocket engines to compression ratio and thus cylinder pressure in a diesel would be combustion chamber pressure and temperature in the rocket engine.  Temperature can be quite high, while pressure is usually somewhat modest compared to peak cylinder pressure in an IC engine.  Rockets don't have to worry about engine production of NOx, however, because they aren't burning air.  There isn't any nitrogen in the LOX to convert to oxides of nitrogen.  I don't know about what happens when the hot exhaust hits the air.

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Offline IRobot

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This is the breakthru diesel, and the guy is going out of business

http://peswiki.com/index.php/Directory:Massive_Yet_Tiny_%28MYT%29_Engine

http://www.angellabsllc.com/Louis_J_Faix.html
That is a swing piston engine, a concept with almost 200 years.

There are a lot of engine design alternatives but they all have some strong disadvantage, otherwise the automotive industry would use them widely. A good example is the rotary engine (Wankel).

Online Stormbringer

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in the military diesel fuel is classified with a JP followed by a number Kero is a JP and kero is basically diesel. therefore rockets certainly do use diesel. I'm just saying. and i thought this had more to do with a combustion effect rather than the mechanics of a diesel engine.

an interesting aside: the principle of the Diesel engine is actually thousands of years old. Native tribesmen in the east have used a hand crafted diesel cylinder to make fire for untold centuries. it's called a fire piston now.
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Offline ChrisWilson68

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in the military diesel fuel is classified with a JP followed by a number Kero is a JP and kero is basically diesel. therefore rockets certainly do use diesel. I'm just saying.

No, diesel and kerosene are different.  They're both distilled from crude oil and they're both mixtures of hydrocarbons (as is gasoline), but they are distilled to have different properties, because they are different mixtures of those hydrocarbons.

That's why we have different words for them.

and i thought this had more to do with a combustion effect rather than the mechanics of a diesel engine.

The article uses the term "principle of combustion", but it's clear that what it really means is a different design for an engine, just as a gasoline and diesel engine are different designs.  There's no new physics of combustion, which is already well understood.

an interesting aside: the principle of the Diesel engine is actually thousands of years old. Native tribesmen in the east have used a hand crafted diesel cylinder to make fire for untold centuries. it's called a fire piston now.

It's quite a stretch to say that using compression to create fire is the same as the principle of a diesel engine.  Compression is only one part of the whole mechanism of a diesel engine.  If something isn't producing mechanical energy from internal combustion, I wouldn't count it as a diesel engine.

Offline RigelFive

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Uhhh.  I've heard about a VW Passat having 75+ mpg.  Rumor is they are made in Tennessee, sold in Europe, but banned in the USA due to over-regulation/US potentially losing all domestic car sales.

http://m.autoblog.com/2013/06/24/vw-passat-tdi-sets-77-9-mpg-fuel-economy-record-through-lower-48/

In the rocket engine world, there was an USAF program named IHPRHP that was to achieve a 2x performance gain in payload.  XCOR could be on the right track.
« Last Edit: 12/01/2013 11:18 PM by RigelFive »

Offline ChrisWilson68

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Uhhh.  I've heard about the VW Passat having 75+ mpg.  Rumor is they are made in Tennessee, sold in Europe, but banned in the USA due to over-regulation/US potentially losing all domestic car sales.

http://m.autoblog.com/2013/06/24/vw-passat-tdi-sets-77-9-mpg-fuel-economy-record-through-lower-48/

What the article linked to actually says is the 77.9 mpg figure was a stunt that was done by a specialist driver who used special driving techniques on a trip that touched all of the lower 48 states.

This is called "hypermiling".  By driving very carefully at particular speeds on carefully chosen roads, you can get much better gas mileage than any person would in the real world.  I don't know about the Passat, but in the Prius, hypermilers drive around 35 mph to maximize fuel economy.  If you want to drive faster, you get much lower fuel economy.  If you want to drive slower, you get much lower fuel economy.  If you start and stop, you get much lower fuel economy.

It claims this is a record.  But only compared to others who have tried driving around to all 48 of the lower 48 states with the specific goal of keeping fuel efficiency high.  How many other cars has that even been tried with?  Nothing in this article says.

And the article also qualifies the record, saying it's in the category of "non-hybrid car".  In other words, all the dozens of high-mileage hybrid vehicles are excluded from the category.

It sounds like a meaningless PR stunt by Volkswagen to me.

There's nothing in the linked article to suggest the conspiracy theory you claim as a "rumor", that the U.S. banned this car out of fear it would take away all domestic auto sales.

In fact, the Passat TDI that the article is about made its 77.9 mpg trip through the United States!  Doesn't that prove pretty conclusively it wasn't banned by the U.S.?

Anyway, a quick check of the website of my local Volkswagen dealer shows the Passat TDI offered for sale there -- with 0% APR for 60 months, no less.  So much for the "banned in the U.S." nonsense.

http://www.stevenscreekvw.com/AboutSpecials_D?p=2013-vw-jetta-passat-tdi-form&cs:e=g&cs:gn=s&cs:cid=37533564932&cs:kw=passat%20tdi&cs:p=&seg=dap&cs:tv=329&cs:a=vw_core_tdi&cs:pro=vwdapnc&cs:ki=635435428

Come on, do a little checking before you post.  All it took was 2 minutes to read the article you posted to plus 10 seconds on Google to find a Passat TDI for sale in the U.S.

In the rocket engine world, there was an USAF program named IHPRHP that was to achieve a 2x performance gain in payload.

That's pretty vague -- do you have a link for that which gives a bit more information?

Offline Jim

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in the military diesel fuel is classified with a JP followed by a number Kero is a JP and kero is basically diesel. therefore rockets certainly do use diesel. I'm just saying. and i thought this had more to do with a combustion effect rather than the mechanics of a diesel engine.


That has more to  do with the Abrams tank and it's gas turbine engine.  To help with logistics, the DOD created a fuel that can be used in both gas turbines and diesels.

Commercial diesel is much heavier than kerosene and is closer to bunker oil

Offline cordwainer

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These new principles have to do with increased control of fuel air mixtures to increase efficiency so they would have little application for rocket or jet engines where the more open combustion chambers and the sheer volume of combustion material and exhaust make fine control of the combustion process difficult. That being said some of what is being applied here might be useful in the next generation of Pulsed detonation jet engines.

Offline RigelFive

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Uhhh.  I've heard about the VW Passat having 75+ mpg.  Rumor is they are made in Tennessee, sold in Europe, but banned in the USA due to over-regulation/US potentially losing all domestic car sales.

http://m.autoblog.com/2013/06/24/vw-passat-tdi-sets-77-9-mpg-fuel-economy-record-through-lower-48/

What the article linked to actually says is the 77.9 mpg figure was a stunt that was done by a specialist driver who used special driving techniques on a trip that touched all of the lower 48 states.

This is called "hypermiling".  By driving very carefully at particular speeds on carefully chosen roads, you can get much better gas mileage than any person would in the real world.  I don't know about the Passat, but in the Prius, hypermilers drive around 35 mph to maximize fuel economy.  If you want to drive faster, you get much lower fuel economy.  If you want to drive slower, you get much lower fuel economy.  If you start and stop, you get much lower fuel economy.

It claims this is a record.  But only compared to others who have tried driving around to all 48 of the lower 48 states with the specific goal of keeping fuel efficiency high.  How many other cars has that even been tried with?  Nothing in this article says.

And the article also qualifies the record, saying it's in the category of "non-hybrid car".  In other words, all the dozens of high-mileage hybrid vehicles are excluded from the category.

It sounds like a meaningless PR stunt by Volkswagen to me.

There's nothing in the linked article to suggest the conspiracy theory you claim as a "rumor", that the U.S. banned this car out of fear it would take away all domestic auto sales.

In fact, the Passat TDI that the article is about made its 77.9 mpg trip through the United States!  Doesn't that prove pretty conclusively it wasn't banned by the U.S.?

Anyway, a quick check of the website of my local Volkswagen dealer shows the Passat TDI offered for sale there -- with 0% APR for 60 months, no less.  So much for the "banned in the U.S." nonsense.

http://www.stevenscreekvw.com/AboutSpecials_D?p=2013-vw-jetta-passat-tdi-form&cs:e=g&cs:gn=s&cs:cid=37533564932&cs:kw=passat%20tdi&cs:p=&seg=dap&cs:tv=329&cs:a=vw_core_tdi&cs:pro=vwdapnc&cs:ki=635435428

Come on, do a little checking before you post.  All it took was 2 minutes to read the article you posted to plus 10 seconds on Google to find a Passat TDI for sale in the U.S.

In the rocket engine world, there was an USAF program named IHPRHP that was to achieve a 2x performance gain in payload.

That's pretty vague -- do you have a link for that which gives a bit more information?
So what I'm saying is that there is a special 1.4L VW TDI Passat sold in Europe that is able to go 1430 miles on a tank of diesel (as demonstrated in the USA on Shell low sulfur diesel).  The link you provided was to a new 2.0L VW Passat that can achieve 795 miles on a tank of diesel.  You are correct about everyone being able to get a 2.0L VW, but the special 1.4L Passat TDI version is not accessible in the USA. 

Here is the VW press release:
http://www.media.vw.com/newsrelease.do;jsessionid=3628B5B913F3C715321DC2AA64E7EB2C?&id=1408&allImage=1&teaser=volkswagen-passat-tdi-clean-diesel-sets-world-record&mid=

If somebody wanted to totally get people infuriated (worse than mandating ObamaCare), they would mandate that everyone had to drive the 1.4L VW TDI Passat to achieve 75-80mpg.  Someone was joking on a blog that they rented one in Europe and it would redline at 3000 rpm.  There was no appreciable torque, so the car would be useless for getting up a hill in San Francisco.   The 1.4L Passat goes ZERO to 60 mph in 10.5 seconds (WITH A &%*$%*%&$ TURBO!). 

The Nissan Leaf will SMOKE the 1.4L TDI Passat off the line in a 0-60 drag race.

So I think we can likely agree that PERFORMANCE and EFFICIENCY are not likely to be seen at the prom together...

Offline ChrisWilson68

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Uhhh.  I've heard about the VW Passat having 75+ mpg.  Rumor is they are made in Tennessee, sold in Europe, but banned in the USA due to over-regulation/US potentially losing all domestic car sales.

http://m.autoblog.com/2013/06/24/vw-passat-tdi-sets-77-9-mpg-fuel-economy-record-through-lower-48/

What the article linked to actually says is the 77.9 mpg figure was a stunt that was done by a specialist driver who used special driving techniques on a trip that touched all of the lower 48 states.

This is called "hypermiling".  By driving very carefully at particular speeds on carefully chosen roads, you can get much better gas mileage than any person would in the real world.  I don't know about the Passat, but in the Prius, hypermilers drive around 35 mph to maximize fuel economy.  If you want to drive faster, you get much lower fuel economy.  If you want to drive slower, you get much lower fuel economy.  If you start and stop, you get much lower fuel economy.

It claims this is a record.  But only compared to others who have tried driving around to all 48 of the lower 48 states with the specific goal of keeping fuel efficiency high.  How many other cars has that even been tried with?  Nothing in this article says.

And the article also qualifies the record, saying it's in the category of "non-hybrid car".  In other words, all the dozens of high-mileage hybrid vehicles are excluded from the category.

It sounds like a meaningless PR stunt by Volkswagen to me.

There's nothing in the linked article to suggest the conspiracy theory you claim as a "rumor", that the U.S. banned this car out of fear it would take away all domestic auto sales.

In fact, the Passat TDI that the article is about made its 77.9 mpg trip through the United States!  Doesn't that prove pretty conclusively it wasn't banned by the U.S.?

Anyway, a quick check of the website of my local Volkswagen dealer shows the Passat TDI offered for sale there -- with 0% APR for 60 months, no less.  So much for the "banned in the U.S." nonsense.

http://www.stevenscreekvw.com/AboutSpecials_D?p=2013-vw-jetta-passat-tdi-form&cs:e=g&cs:gn=s&cs:cid=37533564932&cs:kw=passat%20tdi&cs:p=&seg=dap&cs:tv=329&cs:a=vw_core_tdi&cs:pro=vwdapnc&cs:ki=635435428

Come on, do a little checking before you post.  All it took was 2 minutes to read the article you posted to plus 10 seconds on Google to find a Passat TDI for sale in the U.S.

In the rocket engine world, there was an USAF program named IHPRHP that was to achieve a 2x performance gain in payload.

That's pretty vague -- do you have a link for that which gives a bit more information?
So what I'm saying is that there is a special 1.4L VW TDI Passat sold in Europe that is able to go 1430 miles on a tank of diesel (as demonstrated in the USA on Shell low sulfur diesel).  The link you provided was to a new 2.0L VW Passat that can achieve 795 miles on a tank of diesel.  You are correct about everyone being able to get a 2.0L VW, but the special 1.4L Passat TDI version is not accessible in the USA. 

Here is the VW press release:
http://www.media.vw.com/newsrelease.do;jsessionid=3628B5B913F3C715321DC2AA64E7EB2C?&id=1408&allImage=1&teaser=volkswagen-passat-tdi-clean-diesel-sets-world-record&mid=

If somebody wanted to totally get people infuriated (worse than mandating ObamaCare), they would mandate that everyone had to drive the 1.4L VW TDI Passat to achieve 75-80mpg.  Someone was joking on a blog that they rented one in Europe and it would redline at 3000 rpm.  There was no appreciable torque, so the car would be useless for getting up a hill in San Francisco.   The 1.4L Passat goes ZERO to 60 mph in 10.5 seconds (WITH A &%*$%*%&$ TURBO!). 

The Nissan Leaf will SMOKE the 1.4L TDI Passat off the line in a 0-60 drag race.

So I think we can likely agree that PERFORMANCE and EFFICIENCY are not likely to be seen at the prom together...

That's interesting.  Hopefully we can agree that the reason the 1.4L TDI is available in Europe and not the U.S. is because VW thought it would sell better there than in the U.S., not that it was banned in the U.S. :-)

Offline RigelFive

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There is an emission standard in the USA that keeps the high mpg engine from being sold.  The compression ratio for best fuel economy does not generate the best emissions when the analysis considers grams of CO2/fuel volume.  If they simply considered less fuel is consumed, there would not be any need for this ban.  But if you consider less fuel being sold, less tax revenue generated, a major impact to US car sales; then you can see the motivations to NOT have them sold in the USA.

Rather than marvel at efficiency, we should do the opposite.  We should marvel at performance and fuel inefficiency.

Gimme an F-1X with greater fuel consumption!!!  Have to add weight to increase the performance?  AWESOME!  Line the combustion chamber in deep fried beer batter and bacon.  Then we can do this!

« Last Edit: 12/03/2013 01:21 PM by RigelFive »

Offline IRobot

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The Nissan Leaf will SMOKE the 1.4L TDI Passat off the line in a 0-60 drag race.

So I think we can likely agree that PERFORMANCE and EFFICIENCY are not likely to be seen at the prom together...
The Mercedes C220 CDI will do 57 mpg, top speed of 232km/h and 0-60mph in 8.4s. Unfortunately it does not seem to be sold in the US.

Offline avollhar

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So I think we can likely agree that PERFORMANCE and EFFICIENCY are not likely to be seen at the prom together...

Not Diesel, but Performance and efficiency CAN go together :)
http://en.wikipedia.org/wiki/BMW_i8

75.1 mpg and 362 bhp combined electric+gasoline (of course not at the same time). Going on sale in the US 2014/2015.

I'll take its smaller sister (BMW i3) for a spin next month  ;D




Offline ChrisWilson68

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Is that sound I hear the last tenuous link to space flight snapping?

Offline RigelFive

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Ok.  I'm trying to get into Professor Naitoh's articles/press releases.  There really are no details as to how this increase in efficiency / performance are brought into practice.  I'd just assume that the work is valid and give the group full credit.

However, the pictures of the engine being tested really don't appear ready to replace a Lycoming IO-540 just yet. 


Offline JohnFornaro

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so there are no diesel fueled rockets because ....................... ?

.... uhhhh... because kerosene is better?
Sometimes I just flat out don't get it.

Offline RigelFive

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so there are no diesel fueled rockets because ....................... ?

.... uhhhh... because kerosene is better?
Forget diesel and kerosene, RP-1 is the fuel for rockets.  Kerosene has all of the extra *stuff* for corrosion prevention/ice/fungus/etc.  Makes me cringe thinking of what people are breathing with kerosene heaters these days.

Offline ChrisWilson68

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so there are no diesel fueled rockets because ....................... ?

.... uhhhh... because kerosene is better?
Forget diesel and kerosene, RP-1 is the fuel for rockets.  Kerosene has all of the extra *stuff* for corrosion prevention/ice/fungus/etc.  Makes me cringe thinking of what people are breathing with kerosene heaters these days.

When people talk about Kerosene with respect to rockets, they mean RP-1.

Kerosene is a broad term that encompasses several very similar grades of fuel.  RP-1 is a specific type of Kerosene.

Offline cordwainer

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I wonder if a micro-rockets could be used to ignite the fuel flow inside a larger rockets ignition chamber? Or be used to make more efficient gas regenerators for powering fuel pumps?

Monopropellant rockets using catalysts or a heating element would ignite a larger stream of fuel inside a reaction chamber could make for more efficient burning of fuel by creating a vortex effect.

Another possibility would be to use a thermo-power wave device powered by the rockets fuel to create electrical energy, exhaust from the device could in turn be used to power a Stirling motor for further power generation.

Offline ChrisWilson68

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I wonder if a micro-rockets could be used to ignite the fuel flow inside a larger rockets ignition chamber?

Why?  Just injecting TEA-TEB into the chamber seems simpler to me, and just as effective.  Micro rockets would be more complex hardware that something could go wrong with, or that could interact with the rest of the main engine after ignition was done.  It would also be more mass.

Or be used to make more efficient gas regenerators for powering fuel pumps?

How could having micro rockets possibly make the gas generators more efficient?

Monopropellant rockets using catalysts or a heating element would ignite a larger stream of fuel inside a reaction chamber could make for more efficient burning of fuel by creating a vortex effect.

I don't see how that would make anything more efficient.

Another possibility would be to use a thermo-power wave device powered by the rockets fuel to create electrical energy, exhaust from the device could in turn be used to power a Stirling motor for further power generation.

Why would you be trying to generate electricity from the rocket engines of a launch vehicle?

Offline Jim

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I wonder if a micro-rockets could be used to ignite the fuel flow inside a larger rockets ignition chamber?
Or be used to make more efficient gas regenerators for powering fuel pumps?

They already exist. Augmented spark igniters
Gas generators are by definition not efficient so as to keep the combustion temp down for the turbines.

Offline BobCarver

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Why would you be trying to generate electricity from the rocket engines of a launch vehicle?

Theoretically, you can boost the thrust of a rocket in atmosphere by several hundred percent using magnetohydrodynamic principles. See AIAA 95-4079 Rocket-Induced Magnetohydrodynamic Ejector A Single-Stage-to-Orbit Advanced Propulsion Concept.


Offline cordwainer

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As to thermopower wave I was thinking more along the lines of generating electricity for a deep space vehicle but you could use the power generation for turbo-pumps in a launch vehicle. For a replacement to conventional gas turbine generators or regenerators such a device might actually save weight and decrease complexity though.

 The micro-rocket combustion chamber injection idea though would require larger more complex micro-rockets that would definitely add weight. Might be useful in an air-breathing design though.

Offline llanitedave

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None of this holds a candle to the celebrated turbo encabulator!


« Last Edit: 12/14/2013 07:54 AM by llanitedave »
"I've just abducted an alien -- now what?"

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