h a l f b a k e r yGuitar Hero: 4'33"
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the advantages of external combustion are numerous:
firstly external combustion can be controlled in a manner
to leave no fuel un-burnt. secondly, related to the first
reason, exhaust gases are cleaner, thirdly should the
need
arise to 'swop' fuels (say from gas to coal) can be easily
achieved
(performance will be affected) by changing the
combustion chamber and exhaust system and refitting
the
heat exchanger. i am sure there are other advantages.
the helium turbine engine consists of such a chamber
connected to a completely closed (no valves, no gaskets,
kind of like a bubble) system starting with a heat
exchanger. milled from copper or brass this first part of
the closed system heats a propellant gas comprised of
helium (because of its amazing co-efficient of
expansion)
(hydrogen could be used), another gas that evades me
(nitrogen is plentiful and cheap) with a relatively high
molecular mass, and water (for the ability to retain heat
and its molecular mass). this gas would thus expand
fast,
is cheap enough to mass produce, and stay hot.
once suitably hot the gas will be able to spin a specially
designed turbine attached to a strong light weight
permanent magnet. all of this is encased in the milled
copper or brass closed system. an induction coil (if
necessary - the body is made of copper) will harness
electrical current. the gases onced passed through the
turbine reduce in temperature and pressure before re-
entry to the heat exchanger. this engine is not designed
for racing cars - a ships motor would be more suitable.
once the gasses have heated up sufficiently the engine
should idle with very little fuel being burnt to maintain
its
temperature. did i mention the copper housing is also
insulated perhaps vacuum flask style or glass insulation
fibres. from the outside you should be able to touch it
comfortably with your hand > hence keeping the energy
in
the system besides out the electrical induction.
in order to create useful wattage, forcefully increase fuel
consumption and rotation of the turbine.
in my opinion this is a clean, efficient engine - if not the
most versatile.
wiki helium
http://en.wikipedia.org/wiki/Helium
helium has special properties [codrakon, Jul 26 2009]
Stirling Cycle Engines
http://en.wikipedia...iki/Stirling_engine
[MisterQED, Jul 26 2009]
[link]
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1. I'm not exactly certain how the engine is supposed to exactly burn helium. It's a stable, noble gas which doesn't 'burn,' per se. If you want to make large amounts of plasma with it then you have to have a power source. And never mind the 'clean' part, the exhaust would be pretty nasty. |
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I am afraid mr Steel you have missed the point i
think. this engine uses the helium combo as
propellent gas to turn a magnetic turbine inside a
copper chamber. the propellant gas is heated via a
heat exchanger that can use heat from different
types of fuel. |
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the fuel is burnt externally from the actual
propellant. just like a Stirling motor would work. |
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this engine has nothing to do with plasma. |
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fuel efficiency is achieved by the fact that there is
much more control when burning the fuel
(compared with an internal combustion engine).
how
much actual charcoal is left in a fire that has
enough air and is burned it self out? almost none
in most cases. perhaps a better example would be
a typical gas stove or panel heater. |
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so what you're proposing is a steam engine with recovered helium instead of water. |
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What makes He more suitable than H2O ? |
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helium expands a lot faster than all gases because
there are only very weak forces between
individual atoms, and the atomic mass is only 4.
for every degree heated helium will expand faster
than another gas. this is the first part of the gas.
it increases pressure in the chamber. |
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water is used in the gas because it retains heat.
please dont ask me how but try this - boil a cup of
water and measure the rate at which it cools, say
for example when compared with alcohol. |
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i am saying that in combination that the
propellent will increase in pressure and stay at
higher pressures for longer, thereby increasing the
engines efficiency. |
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still, a conventional fuel as the basic energy source. I don't think this is going to power any plasma jet fighters. |
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i agree [WcW] this wont power plasma jet fighters. i
didn't realise the plasma jet discharge engine was so
impractical. it would be nice for trains, ships and
maybe even cars. |
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So it's a turbine Stirling cycle engine with an enclosed generator? Though possibly not baked, it seems a standard though less efficient logical extension. (-) Unless you can provide some advantage over the piston version. |
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I gotcha. There might not be much ash after a charcoal fire but there certainly is a good deal of smoke. |
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yes there is a lot of smoke initially but it has more
to do with the fuel than anything else - you cant
burn ash - therefore complete combustion is
evident. |
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it is possible to provide a much simpler mechanism
for oxygen to reach the places that need it
most with external combustion. charcoal burns
cleanly once the fire is hot. anyway this engine
will not run on charcoal, but i had to demonstrate
the ability to use different fuels fairly easily. this
engine would mostly run on methane or fossil fuel
derivatives. |
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i am not really in favour of fossil fuels but the
point with this engine is that it will be so efficient
to run (think about the idling requirements - very
little friction and a long lasting hot high pressure
propellant) it will use our resources at a much
slower rate (less pollution) for equivalent power
outputs of a conventional engine. also because
the fuel is burned more completely - with no need
for additives like lead or the lead replacement -
the by products of combustion contain much
fewer impurities (anything that is not CO2 or H2O)
and thus it can be exhausted strait into the
atmosphere, with minimal need for catalytic
converters. essentially the toxicity of exhaust
gasses is determined by the purity of the fuel and
the complete burning of the fuel (supply enough
oxygen). |
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if this motor is all that i think it may be, it is finally
a realistic alternative for our inefficient internal
combustion engines - that can still reach the same
power output. |
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if anyone thinks hydrogen cell (or H2 burning) or
battery powered electric vehciles are the future
they are mistaken. firstly to do this on a massive
scale petrol stations would have to be radically
altered or made redundant which costs
megabucks, secondly to extract hydrogen from any
compound is always endothermic in the end (i'll
explain if necessary). thirdly batteries use a lot of
mineral resources to manufacture (typically) and i
seriously doubt that there is enough material on
earth to go around. fourthly batteries are a
problem to recycle and dispose of at end of
vehicle life. fifthly if the electricity to power
these batteries does not come from renewable
sources, whats the point if they just add another
layer to the energy conversion process (ie from gas
powered power stations into your car) which is
just moving the energy wastage around a bit. |
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i think with a team of engineers on an engine like
this for a couple years, man will finally be able to
move on from a huge fossil fuel dependance to a
smaller requirement. |
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did i mention this engine is also almost silent? |
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I reckon you ditch the water... why would you want to retain heat in the working fluid? Also to be honest Jim would have said the following... |
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"Jim has been observing external combustion engines of which the good old steam engine is an example. He figured if people had had more helium at the time they would have used that instead of steam... |
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In anycase Jim figures a helium engine is more efficient because the helium coefficient of expansion is so great. He also reckons the lower density of the gas would suit a turbine rather than a piston..." |
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*chuckle* about it being almost silent... |
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why would it not be almost silent. there are no
loud
bangs of explosions, fires do not make that much
noise, turbines (especially in a closed system like
this) make a whirring sound. with the right
insulation
i think this motor would be silent. |
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the lower density of the gas is not going to suit
turbines - hence the second gas in the mixture -
which in this dialogue i have suggested as
nitrogen. perhaps something like the old CFC
would be much better because of its density. |
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in this motor a turbine is a better choice than a
piston because: rotational momentum is
maintained longer because there is less friction
against the (non existent) cylinder walls. the
magnet is the turbine - fewer moving parts (1
moving part in total (excluding the combustion
chamber)) and less weight. this turbine would be
designed in such a way as to maximise kinetic
transfer from the gasses to the turbine. |
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retaining heat in the working fluid is a good idea
because less energy is needed to maintain an idle.
if the gas where lets say 400 Celsius dropping 1
degree a minute for five minutes. when the
requirement to increase the turbine speed
happens less energy is needed to increase the
temperature back to 400 Celsius, and it would
happen faster than a gas left to loose temperature
unabated. question: why do many engines have an
optimal operating temperature? - because it
increases efficiency and reduces wear. |
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whos jim anyway? or am i slightly retarded? |
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//why would it not be almost silent.// I'm chuckling along with [madness]. 'Course, he can't tell, 'cause he's (wisely) got his earplugs in. |
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If you're using a turbine in the combustion stream, it can't be a closed system. It has to be open. And jet engines are notoriously not //almost silent//. |
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i am not using a turbine in the combustion stream.
from reading the post one will conclude that it is
powered by a heated propellant gas that is heated
via a heat exchanger |
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You have left out two vital components. After the gas has passed through the main turbine, it will need to pass through (1) a cold side heat exchanger, and (2) a compressor. Otherwise there will be no circulation. |
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Copper or brass would melt unless the temperature (and therefore efficiency) were kept low. |
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Hydrogen or helium are good choices as the working fluids in heat engines, but not for the reasons stated. |
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sp. "comprizing helium" or "consisting of helium", not "comprized of helium". |
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//retaining heat in the working fluid is a good idea because less energy is needed to maintain an idle. if the gas where lets say 400 Celsius dropping 1 degree a minute for five minutes. when the requirement to increase the turbine speed happens less energy is needed to increase the temperature back to 400 Celsius, and it would happen faster than a gas left to loose temperature unabated.// Sorry, but that's complete rubbish. It's like saying that if I carry a load of bricks on my bike it will lose speed more gradually and therefore take less energy to bring back up to speed. |
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I was thinking about a closed loop heat engine like this a few moths ago. Compared to a reciprocating Stirling engine the hot and cold sides could be farther apart, and it may be easier to seal. |
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//from reading the post one will conclude that it is powered by a heated propellant gas that is heated via a heat exchanger// Well, you might, bein' as you wrote it. That info isn't expressed in the post, though. Your writing failed to pass along what you're thinking about. |
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You wrote that the helium/working fluid is contained in a completely closed, bubble-like system, no gaskets or such. In such a structure, you could vary the pressure of your working fluid, but it wouldn't *go* anywhere (like a bubble, you said, remember?) and since a turbine is only useable in a stream of *moving* fluid, it must not be inside the bubble structure. Hence the turbine is in the combustion stream. |
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Reading your writing is difficult. Expecting others to go beyond it to reading your mind is not reasonable. |
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[Lurch} i am working on it. |
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fantasy science. recooling of the helium would have to ocur somewhere. |
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