Water injection and alcohol fuel 14

[patprimmer]

azmios.

Unless I really missed something somewhere, if the power from the steam pressure is more than the power absorbed to convert the water to steam, you have an over unity device. ie you just destroyed the classic laws of thermodynamics and can now build a perpetual motion machine that will contribute work to the outside as well as sustaining itself.

Now if we can also turn lead to gold we can control the worlds power and wealth.

Regards
Pat
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[Slim3]

Pat, you mean that you can heat air and get just as much power as heating water and turning it into steam? I didn't know that. Why didn't steam engines just heat the air and not bother with the water? Does heating air give you the same expansion power as turning water to steam?

That still don't explain to this uneducated mind why in my test runs that an injection of 50/50 water/alcohol out performed any other mixture ratio in either direction. And did it in a good 318 Dodge and a worn out 318 Dodge. The company that gave me the injection systems made that claim and I had to test it because I couldn't understand why and I still don't understand it.

Slim3

 

[azmios]

140, let's make it simple. Once fuel is ignited, there will be lots of heat released. Heat alone will not move piston or turbine, but expansion of gas will. If I ask my 9 years old son to put down a burning campfire or cool off hot metal quickly, he will not use gas or fan, instead he will use water. Similarly, if I dont absorb the combustion heat in a turbine or piston engine quickly, lots of heat will be absorbed by the metal, coolant and the combustion gases. Once the combustion gases absorb the heat, it will expand and pushes the piston down.

The combustion gases consists mostly of N2 and CO2. Both have low specific heat capacity meaning that it will absorb some heat but it is not the best medium. Let's assume if we can somehow introduce water in the combustion chamber preferably when ignition event is about to end, the water in liquid state will absorb heat, until it reaches the boiling point. Once it boils, it will absorb a lot more heat in order to change its state to gas. Even in gaseous state, the specific heat capacity is still higher than N2 or CO2 thus it will continue to absorb heat until equilibrium is reached.

Once the water turns into steam, you can use the gas constant R to calculate the pressure increase (to move the piston downward) using ideal gas law. This is what those SAE and Nasa technical papers are trying to tell us.

I do agree with your opinion that water does not make power, nothing wrong with this as water is not a fuel. However, water is really helpful in absorbing the combustion heat and to expand to make work. Also, if you read the SAE papers, water can function as an energy carrier in which you can heat up water before it is injected into the combustion chamber. This will speed up the change from liquid state to gaseous state. Check out the work done by Transonic, they use fuel as an energy carrier by heating up the fuel before it is injected into the combustion chamber.

 

[azmios]

Pat, I beg to differ. The heat released from fuel is always more than the kinetic energy created after that. How can you have over unity unless someone is blinder than a blind squirrel???

Water in both liquid and gaseous states naturally have very high specific heat capacity meaning that it wont stop absorbing the heat until equilibrium is reached. The hotter the steam becomes, the bigger the gas expansion is. That's I quoted the use of specific heat capacity and gas constant R.

 

[azmios]

hemi, where are you? we need to debate further about this water injection as I have all the time to do so.

 

[hydroman247]

This is extremely interesting. Do you have any articles or research papers you can link us to azmios?

Thanks

 

[azmios]

hydroman, scroll through my earlier replies. many of them are available for free, i have included the links

 

[patprimmer]

There seems to be some misuse of some very technical sounding words here.

I detect an attempt at BS baffles brains type sell job.

Nothing, if it's colder than it's surroundings, no matter what it's specific heat, will stop absorbing heat until equilibrium is reached. That is kinda what equilibrium means and it has nothing to do with specific heat. This is simple high school physics.

Regards
Pat
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[azmios]

"Nothing, if it's colder than it's surroundings, no matter what it's specific heat, will stop absorbing heat until equilibrium is reached. That is kinda what equilibrium means and it has nothing to do with specific heat."

Heat absorption has a lot to do with specific heat capacity. That's why some rankine cycle uses liquid that has greater specific heat capacity. Also, if you compress water, the specific heat capacity tend to go up and therefore becomes better heat absorber.

You can read all of these in the papers that I listed above. Since these papers are peer reviewed and written by specialists in those areas, I would rather trust these authors than someone who makes a living as a textile engineer and never publish anything in engine journals.

 

[Lou Scannon]

azmios,

The title and abstract of the SAE 2009-01-2808 paper are as follows:

Feasibility Study of a Novel Combustion Cycle Involving Oxygen and Water
Abstract:
A novel combustion cycle which operates in 2-stroke operation and utilizes a novel exhaust valve timing and lift strategy is proposed to potentially replace the existing Otto and Diesel cycles. Air is replaced with oxygen to maximize the combustion efficiency and to enable broader range of fuels to be used. Water is injected into the combustion chamber to enhance the combustion heat absorption, gas expansion and to function as an energy carrier. Engine secondary heat that will otherwise be wasted to the environment is recovered and reused by the engine. Engine theoretical efficiency and out emissions are predicted to be improved.

I don't need to read the whole paper to recognize that the process described is quite unrelated to water injected conventional cycles. Furthermore, it is a feasibility study only with theoretical results, not proven science; I haven't heard of any practical developents along these lines, have you?

The same comments apply to the other paper you referenced, SAE 2009-32-0047 which is by the same author, I might add.

I could not locate the Turner and Pearson paper on the web.

Would you care to quote the passages from the US Army and NASA papers that state adding water increases power?

"Schiefgehen will, was schiefgehen kann" - das Murphygesetz

 

[azmios]

Hemi, good to hear from you again. For the US army, read the first section of the conclusion and also the additional expansion in Figure 8 PV diagram. For the nasa paper, try this one "Analysis of Gas Turbine Engines Using Water and Oxygen Injection to Achieve High Mach Numbers and High Thrust" by Hennebery and Snyder.

I have with me the paper from Turner and Pearson, not sure whether you can get the softcopy for free.

As for the 2009-01-2808, the proposed concept is too complex and if you attend the previous SAE congress, many of what proposed in the paper are broken down into sub areas, like oxygen combustion, heat recovery, 2 stroke with poppet valve, etc. If you combine all these smaller researches, we may get something closer to what proposed in the paper.

 

[Lou Scannon]

I read the NASA paper, and apart from the fact that the heat engine cycle they are investigating is drastically different from that of a reciprocating engine, I did not see any claim that adding water directly increased power, only that adding water allowed more power to be made. The analyses that are presented show trajectories of hypothetical engines with water injection proceeding through their missions, but do not include any comparisons of a given operating point, with water injection manipulated as an independent variable at otherwise constant conditions. So, unless there's something I missed, nothing in this paper supports your claim.
It's difficult to understand what is prompting you to peruse these esoteric studies of hypothetical engines and draw conclusions about how water injection affects traditional reciprocating engines, that are not supported by the past 70 years of research, development, and established practice.

FYI, I have no personal incentive to pay the $16 price for the copyrighted SAE papers you reference. I assume you have copies of your own, and it would be considered "fair use" if you would quote here the passages that you say support your argument.

"Schiefgehen will, was schiefgehen kann" - das Murphygesetz

 

[140Airpower]

azmios, the descriptions and diagrams of this engine show, as hemi stated, a type of power plant drastically different from standard internal combustion engines. Hence I would not expect that the use of water in the combustion chamber here relates well to water injection in general.
There are a couple of things that raise questions of standard meanings, especially his use of the term "gas constant, R". In science the universal gas constant is given in units of moles, not kg. It is the same for all gasses, not different for each one. So, I'm not sure if there could be other alternative uses of standard nomenclature.
Key features that distinguish this power plant from the standard internal combustion engines are the use of consumables the normal IC engine does not use, pure oxygen and apparently large quantities of water. For that, there is a mobile oxygen generator. Note that the overall efficiency of this engine will depend multiplicatively on the efficiency of that generator, so that if it is 50% efficient, the overall efficiency is only 50% of whatever is the efficiency of the rest of the engine. I think this is a fatal disadvantage.
The use of water appears to be in a "steam engine" mode which is inferior to the simple gas expansion of the IC engine except that the use of water this way can cool the engine without need of any cooling system and it can capture more of the heat of combustion. This is a bottom cycle phase that normally is not worth pursuing in a mobile powerplant, especially since it consumes significant quantities of water that has to be carried or recondensed (involving more weight, space and complexity).
I think this engine could be best suited to a large, stationary application and will require development to prove itself.

It is hard to beat the familiar IC engine for light-weight, reasonably cheap and efficient mobile power. It does not have to carry 1/2 of its reactive material (air) and carries none of its waste product. The fuel is completely consumed and the fuel container weighs almost nothing. Beating its efficiency by a marginal amount is not likely to be worth the trouble if it involves extra complexity.

 

[azmios]

hemi,

I will quote something from Turner's paper once I am back in the office on monday.

The nasa paper is different from a piston engine. However, if we look at it from the point of view of heat engine, there is not much different, there is compression, ignition and expansion. I know that many believes that higher compression ratio makes more power. However, it is the expansion ratio which is more important than the CR. In this context, expansion of steam moves the piston in piston engine. In case of jet engine, the pressure increase provides thrust for the propulsion system.

I agreed with your explanation earlier but much like what slim3 is believing, the power increases is somehow more than what can be achieved from just extending the knock limit. This is the reason why the water injection's benefit is actually beyond what the conventional thinking in the conventional engine. Turner's paper didnt touch much of the scientific reason on why the power increases too.

You're right in saying that the 2009-01-2808 is just theoretical study. I am interested to see how the theoretical points brought up in the can be disputed. You should try challenging the study made in that paper.

 

[140Airpower]

azmios, your statement, "I am interested to see how the theoretical points brought up in the can be disputed. You should try challenging the study made in that paper", turns the situation on its head. It is not for anyone to "challenge" assertions made in a paper. It is for you or the author to demonstrate and prove that the exceptional claims made can be realized. Everyone else should have a healthy skepticism. This is the way science is done.

 

[azmios]

air,

gas constant R does not have any unit. just flip the thermodynamics books.

the efficiency of oxygen generator is high. coal power plants in china are already using PSA generator to get oxygen. they get intense flame from coal that is much cleaner if compared to air.

also you should check marine engines from europe that are already injecting water. they made many benefit claims with their system.

you may say that nothing beats the conventional piston engine. at less than 50% efficient, there is nothing worth to shout about. there is still big radiator required and the exhaust gas is still hot. i use these two factors to estimate the efficiency of the engine.

as for the sae paper, what is wrong in proving that the claims made to be wrong? i am a reviewer of many engine and combustion journals and i would normally point out a small point to trigger the authors in making better explanation, clarifications or amendment. the papers normally turn out to be a great ones

 

[patprimmer]

azmios

Instead of quoting NASA papers on jet engines look back a bit further and quote NACA papers on WW11 supercharged piston engines. There is quite a large collection that have actually been studied by a lowly textiles engineer that just may have opened a book or two in other areas over the last 40 odd years.

I can't remember who claimed the use of steam engines proves that water expands with more pressure for the same heat input than does air.

Steam is used as the source of heat is external and large boilers and fires can make a lot of heat. They went out of vogue because the IC was overall more efficient.

Equilibrium and heat transfer is well explained in the zeroth law of thermodynamics. Even a lowly textiles engineer knows that.

Specific heat is to do with the amount of heat required to heat a certain mass a certain amount, not to do with equilibrium.

Regards
Pat
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[azmios]

hi pat,

Agreed with you, the British and Germans injected methanol+water in their supercharger engines during take off. This is covered in Charles Taylor's text book.

If you flip through MTZ about 8 years ago, German government funded a research to compare the steam engine and IC engine. IC engine won without any doubt. What's never been done is the hybrid between IC and steam engine. This should give you the best of both worlds. Imagine the steam expansion magnitude if it is in direct heat transfer with the heat source rather than being externally heated like in the traditional steam engine.

If given a choice between water having specific heat capacity at 4.18 or 6.8. Anytime I would take the 6.8, but this can only be achieved if the water is compressed. Higher specific heat capacity will absorb heat faster from the heat source.

 

[Lou Scannon]

"gas constant R does not have any unit"

come again?!!

"Schiefgehen will, was schiefgehen kann" - das Murphygesetz

 

[azmios]

hemi,

Sorry for that, the unit is kJ/kg*K.