The dream of high pressure steam at to much a cost

Many believe in the divine, over zealous lofty goal, of achieving high efficiency better performance by way of extreme high pressures.

This all well in good for steam turbines and alike, in massive operations, where little gain is worth the extreme expenditure and government over sight of host of safety concerns.

But is it really worth the huge complexity and high tech application, when talking of small engine that has around 50 hp, in a moving vehicle where the safety concerns may never allow it?

1) A turbine is completely different animal, than a reciprocating steam engine.
2) Even if a practical extreme high pressure engine, showed good promise, no government agency is going let it on the road.
3) The gain of high pressure over low pressure, is little, and adds far more cost, weight, and again hug safety concerns.
4) High pressurized steam engine, would wear far faster, have more maintenance problems, and shorter life span of service.
5) A vehicle can not stop and add more water all the time, and high pressure steam engine steam, does not condense well most the water will be exhausted.

I do not see at all the practicality, of high pressure steam engine, even a consideration for Auto Application.
It just does not fit the requirements, of light duty application in a moving vehicle, where safety and minimalist approach is needed.

High pressure steam engines, was not, NOT, where the development of steam was going in small private sector use!
It was going less pressure, way bigger valves, and recycling the heat and water as much as possible.
In doing so, they where achieving good efficiency, in reverse direction, by developing a better engine not try tame high pressure.

A IC engine, while having only a short, high pressure under compression, only works on 80 to 100+ in the cylinder.
And these pressures are inside of the engine, none on the outside structure, so nothing can rupture and cause mass damage or injury.
You may be crazy enough, to feel comfortable around thousands of pounds of pressure, the american public will not.
As that engine and all it adjoined parts, jar and twist around, at some point,that high pressure is going bust out crippling someone or causing death.

People want steam at pressure they feel comfortable with, one that they already around, that is around 50 ish pounds per inch.
That works great, it makes a engine same size as IC, with boilers you can buy of the shelf, maybe heat exchanges and condensers.
Why do you want to complicate it, so it never gets developed, as making so hard you will never get it work or approval for use?

IC engine run peak combustion pressures of well in excess of 1,000 psi, motorcycle engine over 1,500 psi, Diesels up to and above 2,000 psi depending on tune etc.

BMEP is lower, that is the average pressure through the stroke, 125 BMEP is typical of many IC engines on the road at full gallop.

Diesel injector pressures of over 15,000 psi are common. People live with them without even knowing it. The first Diesel prototype blew up and almost killed its creator.

To the best of my knowledge a Stanley boiler has never blown, run at 500 psi to 600 psi standard, the Rocket up to 1,300 psi, depending on who's number is believed. Dobles, F type 1,500 psi.

Tell me, what is the pressure in the refrigerator working away somewhere near you or that air conditioner?

You are talking about pressures that are lower then often seen in home water pressure.

Yes, there are limits to practicality, both for high pressure and for low pressure. Bellow 500 psi and the engine is too big, thermal efficiency drops, above 2,000 psi and things become problematic for sure, well much above 1,500 psi and issues arise. The rang between 500 psi and 2,000 psi will give very similar fuel efficiency, for many instances the lower is better. Less pumping losses, more superheat for a given temperature.

Seriously, if you want to advance the art, get a bunch of technical books and study the thermodynamic nature of steam, plus the history of reciprocating steam engine efficiency. Otherwise, well ignorance is bliss, stay blissed out.

Caleb Ramsby

Manchester (the founder city of the Industrial Revolution) had a network hydraulic power supply to operate factories and machines. It ran from the 1894 until 1972 - at a working pressure of 1120psi (yes 77 Bar) and there were up to 35 miles of pipes. Of course pressurised water is not as dangerous as steam - but even so a burst main under the street must have been something to behold!

Mike

If you are going to be involved with steam power, one of the VERY FIRST THINGS to understand is that pressure in and of itself has NOTHING to do with safety.

A tube 6 inches long and .050 ID can be pressurized to 50,000 psi but it poses little risk because it is so small that it simply can't store much of anything. By the same token, steam is NOT the dangerous part of the equation. Let's look at saturated water and steam, both maintained at 1500 PSIG. The water has a density of 38.9031 lbs per cubic foot while the steam has a density of 3.65582; in other words, the water has to expand more than 10 times when it is converted to steam. Now let's look at the density of saturated steam at sea level pressure; 0.0373018 lbs/cubic foot. Roughly speaking, if that boiler ruptures and the water flashes into saturated steam at ambient pressure, it will have to expand about 1000 times. As you can guess, this expansion will not be slow, it will seem almost instantaneous.

According to Google the word explosion is defined as:

ex·plo·sion /ikˈsplōZHən/ noun: explosion; plural noun: explosions

• a violent and destructive shattering or blowing apart of something, as is caused by a bomb.

• technical - a violent expansion in which energy is transmitted outward as a shock wave.

• a sudden outburst of something such as noise, light, or violent emotion, especially anger.

OOOOOKKKKKK....so, the steam will expand about 100 times when it is released into the air and the water will expand about 1000 times; since violent expansion is the criteria for explosive, we can see that the water is the really explosive part of the mixture.

Since monotubes, forced circulation and natural recirculation water tube boilers all have small storage and carry relatively little water, their danger potential isn't that relatively high.

On the other hand, that "utterly safe" low pressure traction engine boiler may be carrying hundreds of pounds of saturated water. As we recall from the Ohio meet a few years back, when those low pressure water storage devices go off they kill indiscriminately. By contrast, I was once leaning against Bill Ryan's go-kart when the boiler blew while it was carrying about 1000 psi, the POP was so mild I wasn't even sure what had happened.

Design is another factor, those old style boilers (especially fire tube) carry most of the water in one place, if something ruptures at that place all the water is free to expand to steam and escape NOW. I've seen a couple of monotubes rupture and the steam hissed out the rupture like air out of a balloon because the flow was so badly restricted flowing out that tube.

So the claims that high pressure is more dangerous are simply bogus.

Steam car developers had to fight this kind of misinformation and distortion over 100 years ago, let's not do it to ourselves in our own forum.

Ken



Edited 1 time(s). Last edit at 02/24/2015 06:32PM by frustrated.

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If any thing breaks, feed lines, head, or valves, at 1000 lbs this what you have, would not stop sill you turn the boiler off!
Autos get into crashes, the steam engine will be broken apart, you have count on worse scenario happening.
Using wrong bolts not rated, to make repair, could have disastrous results,
Higher pressures = extreme danger, not to think that, is real question why any person would not understand common sense of that?

First again, I understand there is high compression in a IC engine, as well as a steam engine in the cylinder.
But IC petrol engines, do not have high pressure in their intake or exhaust, even with a turbo charger.
High pressure steam engines, not only have high pressure inside, but also all over the outside of the engine, in every component is extremely hot. High pressure steam in steam engine, is in big tubes not small, when they budst under twisting julting forces, they can cause major injury and death

1) Which is smaller and lighter, high or low pressure steam?
2) Which cost more and need more maintenance, .high or low pressure steam?
3) Which is safer and more practical, high or low pressure steam?

So you want 50 hp engine, steam is 2 cycle, and lets just use 3 cylinders.
50 hp * 1.40 losses = 70 hp * 33,000 = "2,310,000" lbs force needed
For ever 1/10 of port area you get 600 ft of travel a minute
High pressure 1/10 = 600 / Low pressure 9/10 =5,400 ft travel
High 3850 / 500 lbs sqr in = 7.7 cubic inches / 3 cylinders = 2.57 = 1.37 stroke and 1.47 dia.
Low 428 / 50 = 8.56 cubic inches / 3 cylinders 2.85 =1.42 stroke and 1.8 dia
So both engines internal dimensions, are very close to same, with high being just little smaller.
But truth is the engine have to be much bigger, for extra think materials, to handle the forces.
So High is bigger than smaller, all components have to be bigger, like boiler, supper heater, heat exchanger, and condenser.
It then not just bigger, but far more heavier, so heavy it's own weight becomes consideration like diesel does.
It no hand down, much higher cost to produce and maintain higher pressure, with only tech certified specialist.
In crash I will take 50 over insane 500 lbs any day, to me and many, light low pressure steam engines is far more practical.

Are you trying to keep steam engines, from being ever used?
Are you promoting high pressure steam use, to keep others out of the steam circle of trust, LOL?
What is it that when you look at reality, of low to high pressure, when low pressure is winner in light automotive use.
High pressure has it's place, in big commercial use, when loots of power and money are the mix!
Not! Not! is small cheap units, that need to be simple, and safety is major concern.

I agree with much of what is said on piston engine at least,but then in time one will also notice that many high efficient piston engines had a low pressure turbine in the mix as well.And that they could be awfully small even when running ...many times the gearbox was bigger than the engine.I have to admit I don't have the last words on turbine compounding but on 20-30 psi(diy turbocharger to steamturbine type setup) 25hp is the size of a football and you still about 5 to 1 rpm reduction to speed match the piston coming off something like a model turboprop 10 to 1 planetary gearset. (turbocharger style turbine want to the prop shaft in the 1000-9000 rpm....19000 on runaway speed like if the shaft,belt,chain or ? broke.
(There are also many engineering compliments changes to match the two together as..one is recirculation on small turbines so that you don't see something looking like (boiler flattening surge) a broke line on start-up for the turbine.)

I cut myself off a little early ....engineering game you are working on for proper efficiency is getting 1000 to 1 total expansion with a combination of the piston and the glorified turbocharger.Which is easier said than done for most DIYer's.
At the same time,autos aren't the only folks runing out of space for steamplants...look at most ships right on down to beckman with the launch that are offering diesel drives.Some of the same on trains.....
Getting better use of that space is the devil in the details...

Amish Man,

Your numbers are off.

For a 1 to 8 expansion ratio the MEP will be(from Marks Handbook) 38.5% of the initial pressure.

For a 1 to 1.67 expansion ratio the MEP will be 90.7% of the initial pressure.

For an initial pressure of 600 psi and a 1 to 8 expansion ratio the average pressure on the piston would be 231 psi.

For an initial pressure of 50 psi and a 1 to 1.67 expansion ratio the average pressure on the piston would be 45.35 psi.

Thus for the same rpm the 600 psi engine would be 19.6% the displacement of the 50 psi engine.

Thus for the same rpm the 50 psi engine would be 509% the displacement of the 600 psi engine.

This is running with the longest practical cutoff for the low pressure engine and the shortest practical cutoff for the high pressure engine.

If you want to make a low pressure boiler and engine go ahead. I see no reason why you shouldn't.

Your insistence that a high pressure system is inherently dangerous and technically unsound is flat out incorrect and ignorant.

That is the most polite that I can be about it.

Caleb Ramsby

Caleb,try doing everything you are doing in the piston...then exhaust that to the turbine that is going to a vacuum at the inlet to compressor of that recirculating turbine.I think you see a little more total expansion than.Just looking at the piston.

If you think about it what I is am talking is DIYer's getting into what old timers called bottoming cycle.While trying to stay with water as much as possible without going to ammonium,etc.As stated it is easier said than done...but there where some in light plants and now geothermo that did do just that.(Kalina ,adams nuke engine,the grumman nuke drone using helium instead of water,etc. comes to mind)

At this time for 30 psi pressure, model jet jocks can pickup ready made model turbines for less than Beckman will sale a piston engine of that horsepower.Now if the turbine guy is in the same vain as guys like Chuck they can get or built a piston from 2cycle engine or in the case of a turbine freak...junk turbochargers.Doing the same kinds of rework to make that steamengine...be it piston or turbine in compound with the first piston cylinder.
The low pressure have more off the shelf parts that a DIYer can afford.....
If you go standalone turbine you still need a governor/ECU among other things to keep that thing from running away.....and higher pressure like upwards of 250 psi which is still got more affordable parts than a 1000 psi piston engine would be using.For a car that changing speed regularly a marriage of piston and turbine looks like a good thing piston doing the bottom low speed torque then the turbine singing at the high end.Granted you will have some of the turbo lag
that internal combustion has with turbos,which is the reason you run free turbine(for "integrated bi turbo". And the compressor is doing same thing as what you guys are doing with compression on piston to "reheat" the residual steam.

Hey Arnold,

Don't really understand what recirculating turbine you are talking about.

Sure, a turbine as a secondary expansion stage will extract more power from the steam.

Doble used them for the blower and condenser fan.

It's all a trade off. You are putting more back pressure on the piston engine with a turbine. Same deal with the HP and LP pistons of a compound engine. A turbine can be seen as a free flowing very large displacement second stage piston, not a perfect analogy of course, but similar in principle.

Possibly better to use live steam to drive the blower and fan. Keep the main engine exhaust free flowing with minimal back pressure.

It is difficult to get more power out of a smaller package then a turbine though. Very low maintenance if designed right too.

To get any efficiency at all out of them though, the blades must be designed and constructed very well, and the steam and blade velocities matched very well through the operational range.

For a home built deal, have you considered designing a version of the "boiler injector" where the condensation of the steam in the throat, plus steam velocity is used to give water pressure. Re-design it to give water high velocity and use a bucket type water turbine, lower speed because of the higher fluid density, easier to gear and construct.

Caleb Ramsby

Caleb,you need to understand I made a living servicing gas turbines....
So you put most of your work in what you seen work on the big plants trying to repeat it in impossible(accord to many )
in micro turbine plants.The recirculation is what you seem with many gas turbines like the old Chysler gas turbine car.
In gas turbine at least they are like diesel in that you use only about 15%max. oxygen in the air ,turn the unit up for more you burn it up.
On steam use of gasturbines you are going the full range of expansion right into it condensing in a steam trap/spray condenser (ammonia like Kalina).But the guys with the steamcharts will tell you that even in partial vacuum there is residual steam.And that only about 8 to 15% of the wet steam drops out in the trap as water droplets.So to farther dry it you send the residential steam into a vaccuum ,then heat of compression going thru the gas turbine compressor.(many geothermo/even nuke units(running helium that does not transmit radiation the way water would) use gas turbines in place of conventional steam turbines.
If you can't make a planetary gear you can go to model jet store and buy one for a JetCat ...that is 25hp 10 to 1 geardrive for a turboprop.If you need a bigger hp. gearbox you can go aviation.But if you have any machine shop experience you can build that planetary drive yourself and make it 15 -20 to one instead of ten to1 like most gasturbine guys do And you got a steam turbine that will direct drive a 1000 rpm piston engine. And still be in 190,000 rpm range that gas turbine wheel runs at.Another thing turbines make really powerful flywheels like many marine etc. piston engine use to smooth power pulses.
That remark about about a turbine being a really big piston is not as far off as you would think.....by the time the piston guys do all the thermodynamic calculations of what is happening.You get the effect of a HP piston compounding into LP piston that is upperwards of 100 times the volume...and all thermo numbers of doing just that.
If that gear stuff is still too much for you can buy the drawing for thier 5hp turbine from Reliable Steam and add a GT15 turbocharger(the turbocharger flow for about 6 times of steam flow from piston engine or boiler).And end up with a 25hp recirulating steam turbine that can direct drive a 1000 rpm piston.You also need a speed control by modifying the waste gate to governor the pressure and/or a ECU checking rpms and pressure.

Hey Arnold,

Personally I don't have an interest in using turbines as a primary or for that matter secondary expander.

Caleb Ramsby

A low pressure engine, should not have, any back pressure when exhausting.
If it does, it is running to fast, or needs way bigger valves.

Gentlemen,
May we get the reasoning clear for once???
Not having final exhaust backpressure or valves that are too small is basic engineering smarts when designing steam vehicle engines. Both are well established givens and not subject to guessing.
Ken and I propose using a radial inflow turbine that is equipped with a variable nozzle ring and geared to the main expander as the second stage of expansion in place of a larger cylinder.
Since a final stage turbine was good enough for the TITANIC, BRITANIC and OLYMPIC, we think the idea has merit. Both of us worked the numbers independently and the advantages are clear as a bell.
Only one historical steam car ever had continuously different cutoff for both the HP and LP cylinders, a lesson obviously ignored or forgotten now.

The concept is to avoid the ridiculous ideas some proposed and failed to realize of using ultra short cutoffs and worthless high speeds to get a high expansion ratios in the unaflow cylinder alone. Thus suffering a jerky torque output and impossible and destructive valve gear acceleration rates, noise and ruinous wear. The flow losses, balance problems, size, cost and weight and with additional heat radiation losses attendant with a piston compound engine should be quite clear.
The guiding principal is to compound to get the desired high expansion ratio by having the piston expander use a longer "short" cutoff, then doing the final expansion in the geared power recovery turbine which exhausts into a vacuum. A smoother torque diagram and yet with a high expansion ratio obtains.
There is an excellent book on radial inflow turbines on Amazon and the SAE bookstore, buy a copy and learn.

Realistic pressure is one thing, supercritical and accompanying temperatures no material can use, are delusions of the uneducated.
Radial engines abandoned goofy bearing ideas shortly after WW-1.
Jim

Well if your running 40 lbs of pressure or less, there is no need for compounding, or any expansion cylinder / turbine.
Turbines are expensive unite to attach, and gas turbines would be pitted by the steam, and wear out fast.
Yes to get high speed with big valves, you must reduce the pressure, to reduce the forces that would limit or destroy them.
Again 40 lbs is acceptable for hp, as a steam engine 2 cycle, and equals that of, 80 to 100 lbs of working pressure of a 4 cycle IC engine.
The older engines, where going to oversize valves, of 4 /10 % of the sqr area of the piston, big improvement over 1/10% or less.
But that is still far to limiting, and no reason not to press those numbers to 9/10 sqr area of the piston, for better performance.
Most of the time the engine, will be working at slow low power gulping steam easily with little restriction and good efficiency.
Only at peak limited demand, will engine whine out hard, being more like IC in high rpm to push out allot hp, and less efficiency.
Having extreme over sized valves, double or triple of any steam engine before, will let it flex it's muscle only when needed.
This will allow the engine to stay small, using torque more than thatt of a diesel can provide, and rpms like a gasoline engine.
And because the over sized valves are being used under light steam, most of the time at slow pulses, longer engine life into hundred thousands hrs.
( |\../| original valve size), ( |\......../| over size valve), ( |\.............../| extreme maxed out valve size)
Timing I plan to do like IC engines, separating intake cam and exhaust cam, then being able adjust the timing.
Adjust the timing of the valves separately, to get near perfect intake exhaust seating, will bring engine to life and give it efficiency.
To get near perfect steam flow, for the rpm and demand on the engine, through out all settings a smooth as can be achieved.
I am talking correlating the pressure in, the flow of steam in, and the flow of steam out, in every power setting.
This may be done mechanical, electronically, or combination of the 2.

Captain Obvious,
Who would be so silly as to build a system for a car running on 40 psi?? That's an old restored mill engine.
Valve sizes and their number are done to suit the use of the engine including pressure and flow rate.
Little things like throttling and cutoff are also factored in.
With a given engine, BMEP determines the power density, while temperature determines the net efficiency.
Gas turbines are irrelevant and have nothing to do with a Rankine cycle system.
A Sesame Seed book on steam engines might be a good read.

Pressure and temperature have little to do with efficiency.
The little gain in thermal higher pressure, that is supposedly gained, is lost in mechanical and flow restriction.
The numbers just do not pan out, regardless of how much you fiddle with them, net losses are more.
Will 40 may not be big enough a pressure for you, it is same working pressure when double them, for being 2 cycle to 80 lbs = to IC.
And what matters more is valve size, valve size determines engine size, not other way around.
How hard is it to understand, bigger hose under low pressure will fill a pool faster, than small hose under high pressure.
Valve size, not pressure, is what should be focusing on.
All the old steam books, said valves were to small, and the valve timing retarted.
Higher pressure requires, compounding, for any expansion.
You can not expand inside the cylinder, it ruins efficient.
Heating to high temperatures, is very heat wasteful, and very complex.
Trying to reclaim high pressure steam heat, is more inefficient.
When engine using lower pressure, higher pressure is just reduced, causing huge efficiency loses.
High pressure under normal operation, is to complex costly with engineering problems, and is way inefficient in light variable application.
Wasting your time, your money, and energy.
You want light cheap semi efficient steam engine for auto, you stay to 40 to 50 lbs at the max, and you get hp by larg valves that lets the engine run fast piston travel of 5,400 ft per min or more.
With piston speed, you get a small compact engine, or is that to hard to understand.
Then you buy tank-less boilers, heat ex-changers, and condensers on the market.
But my opinion is,,, most steam people want to keep this political debate forever, never really build practical usable engine.
This becomes a club of intellectuals, going down tunnel vision paths that go no where, then focusing on the actual practicality.
If you keep it at high pressures, your guarantied it will never come to be, stays in groups like these.
You tell me one running auto engine that runs 1,000 lbs, and steamers come later went down in pressure not up.



Edited 1 time(s). Last edit at 02/28/2015 11:47PM by Amish man.

Amish man Wrote:
-------------------------------------------------------
> Pressure and temperature have little to do with
> efficiency.

If this is your understanding of how an efficient automotive steam systems works, GOOD LUCK.

A vacuum engine, is most efficient engine, but with such a low pressure of vacuum of best 10 lbs, the engine would be big as there is limit to piston speed.
So yes I am right!
Super heating steam, saves on water, when throwing it away and not condensing.
So over heating the steam, is waist full, when condensing and recycling the steam.
For ever % gain in thermal inefficiency raising the pressure, you loss twice in with heat losses, mechanical losses, and flow restriction losses.
Increase the pressure, = greater cost, greater complexity, shorter engine life, and decrease efficiency!
How is there any gain in increasing pressure?
Why is that so hard to understand?
Do the math slight gain for greater pressure = greater loses in application.

This is the steam automobile forum. Your low pressure engine could never make highway speeds. And if you some how built an engine big enough you would not have room for passengers.

You.are advocating technology that is of a lower level than Stanley engines.

The problem with "common sense" is that far too often what "everyone knows" is wrong, and just as often people only listen to what goes on in their own head rather than doing any real analysis (like math) or even, HEAVEN FORBID, research. We all know just how difficult Google has made research and it surely laziness isn't the excuse for persistently going online and posting the same nonsense year after year.

Onto a different topic!

"A vacuum engine, is most efficient engine..."

That's very insightful --- truly a profound insight. Doing some of that nasty, evil research one finds that such engines were built by Thomas Newcomen and others later. In fact, I attached an image of such an ultra modern, hyper efficient engine in all its glorious and magical 20 HP output.... (see below)

One is stunned by the depth of the logic involved in this proposition! Vacuum is the most efficient operating mode, obviously! However, it is also obvious that the engine can't even possibly work at atmospheric pressure, if the pressure inside is the same as outside there is no difference to work against the piston! But the same source tells us everything is great at 50 psi! This was so utterly inspired that I felt I had to graph it out so that everyone could grasp the full impact of the concept. (See "AmishMan Curve" below)

At the brilliantly conceived 50 psi it is very common to get horsepower in the range of only 1500 pounds per 5 HP! (see "Stm Launch"

Of course, if you start reading internet articles on all this sort of technology (I know, I know, that darned research is almost impossible but one must make the effort however tedious) you will find comments regarding the horrible efficiency of the Newcomen engine and the somewhat better efficiency of the Watt, then better yet as the pressures rise for the Cornish pumping engines and so on as pressures ever rose. I say Amishman is right! All of these things are utter lies? Are we to take the word of a mere mathematician such as William John Macquorn Rankine? Certainly not! Are we to believe the ramblings of Johan Stumpf? What did he know other than verifying his math against the actual results of engines built to his designs? Even such "practical" men as the writers of the "Colliery Engineer Pocketbook" knew not of what the said! "Colliery Engineers Pocket Book of Lies"

I put it to you, good folks. From now on we should ignore calculations and research; instead we should simply rely on what our common sense and personal desires indicates is correct. What does iron and steel or math and experience have to offer that is better than simply posting whatever thought idly crosses our minds without contemplation?

Onwards and Upwards!

You have to calculations you need take into account, the pure clean thermal gains math verses the application losses.

The thermal pure thermal gains says, you get more lbs cubic inch hp, at greater hp
But this is not a major significant gain, but slight slope, that needs lots of temperature & pressure to see and significant benefit.

Losses of increased temperature and pressure are many, it my feeling & assertion add up to too much losses.
1) Heat, to heat high pressures, much lower temperature % is lost, and thrown away.
2) Heat again, the whole system at high heat must be insulated, as losses are huge, at high temperatures.
3) Pressure, means everything must handle extreme stresses, loss in friction on bearings, piston rings, and all moving parts.
4) Steam flow, high pressure losses significant losses, in all bottle neck of transmission of steam.
5) condensing and recapture of the heat, most steam has expanded, is much cooler at no pressure and very little heat can be recovered.

There 2 sides 2 the equations, there is to much focuse on thermal gains, and not enough on piratical application losses.

A 40 lb steam engine can not produce enough hp or be to big, this is hog wash.
A 1 litter engine, running on 40 lbs, can provide all hp to move a auto.
Remember lower pressure allows for bigger valves, valves 90 % of area of the cylinder is 9/10
For ever 1/10 we get 600 ft per min of travel, so 9/10 gives 5400 ft of travel.
1 liter = 61 cubic inches. 61 * 40 * 5400 = 13,176,000 / 33,000 = 399 hp but only 1/4 cycle is work = 99 hp - mechanical & flow losses 1/5 =(80 hp)
This is as much hp as my 2.2 l chevy motor, and only takes 5 to 10 hp to go down the road.

Ken,
Oh Phooey, now you ruined my dream of a new car with a walking beam low pressure steam engine in it.
You know, the one with the 4' bore and 9' stroke racing along at 35 rpm.
More like posted with no concept of how the Rankine cycle works or the thermodynamics behind it.
So simple when you ignore a hundred fifty years of hard won research.
Jim

Ken,

So right, I tried to google the "piratical application losses" and couldn't find anything. I can only surmise that they are akin to the "gremlins" often found in engines, but more insidious and prone to breaking out in song.

They may even be led by a lethargic Christopher Walken!

Caleb Ramsby

Hey, Amish Guy.

Jim Crank has owned a variety of steamers and assembled the car that took the Land Speed record.

Caleb has analyzed the subject extensive AND published his calculations for anyone to examine.

I've worked in Powertrain Engineering at General Motors for 20 years and have 24 years naval experience with steam propulsion and auxiliary systems.

Stumpf, Rankine and every book on thermodynamics agree with us. So do every volume I can find reporting actual experimentation and operation.

You, on the other hand, make a bunch of assertions and produce nothing to back it up.

You keep talking about application losses but obviously you have never taken the effort to actually study the subject and simply pull stuff out of air. Look up FMEP (Friction Mean Effective Pressure). Friction MEP is the amount of MEP that is lost just to compensate for the engine's friction losses and for any given rpm it is pretty much constant no matter how much the engine load varies. The MEP, however, is going to depend on the admission steam pressure, clearance volume and cutoff. Suppose our FMEP is 20 psi at whatever rpm we are running. If our steam provides an MEP of only 19 psi the engine will not even run since it consumes one more psi than that just to turn over WHILE PRODUCING NO WORK. At 20 psi the engine will spin but will slow if you apply even the tiniest load. At an MEP of 25 psi the effective MEP after subtracting the FMEP is 5 MEP....5 divided by 25 equals 0.20 Now suppose our MEP is 150 psi. Subtracting 25 FMEP leaves 125 MEP and dividing the 125 by the original 150 leaves us with 0.8333. So guess what? That's 4.167 TIMES better utilization of the available pressure... This factor alone blows all your unsubstantiated assertions out of the water. On average, mechanical efficiency goes up with MEP. Since higher temperature and pressure also produce HIGHER THERMAL EFFICIENCY, your argument gets blown even higher out of the water. A more thermally efficient engine running with higher mechanical efficiency is going to whallop the tar out of a less thermally efficient engine with less mechanical efficiency.

Now, before you go making more wild statements that contradict every physicist, engineer and technician in sight, perhaps you should provide some evidence to back up your claims. Where are your tests showing the efficiency improves as your pressure drops? I want to see any studies showing that vacuum is the most efficient source of power. (OK, I had to stop typing to get the laughs out of my system after that last one). Perhaps you could supply real calculations using standard and widely accepted formulas to back up your position.

Come on, you are the one claiming that almost everyone in the world is wrong and you are right. It is your duty to prove the case extensively and definitively... Sometimes one guy is right and everyone else is wrong. Sometimes, but not very often.

Waiting for a reply filled with facts (actual reports of engine testing) and reasoning (based on calculation using accepted formulas and not your assertions that such things are true).



This isn't high math, new or unusual calculation or anything else. This is one of the more basic functions facing the design of real world engines.

So what are we seeing?

FIRST: Thermal efficiency goes up with temperature and pressure as per Carnot, Rankine, Stumpf and the wino on the corner.
SECOND: Mechanical efficiency can improve with higher MEP because the losses due to friction and pumping are lower in relation to the energy put into the system.

Yes, there are points where you can go too far with a given basic technology, but determining those points is quite difficult and not just a matter of picking some arbitrarily low figure. Obviously supercritical pressures look highly problematic for a piston engine for a number of reasons; valve acceleration is too high for the materials involved, the very brief opening and closing times lend themselves to severe wire drawing issues and it is vanishingly difficult to achieve a high enough expansion ratio to avoid wasteful under expansion. Claiming that 50 psi is the "butter zone" is ridiculous, however, because the documentation to the contrary is overwhelming unless you wish to begin claiming a wild conspiracy.



Edited 1 time(s). Last edit at 03/01/2015 02:11PM by frustrated.

All,
I got it, I got it, I discover what is going on!!!!! And you guys thought vaudeville was dead.
A graduate of the Cyclone School of Delusion and Wild Statements With No Supporting Facts.
Research and honest testing are passé, wild assumptions from comic books, funny cigarettes and phony test data are in. Saves so much in time and money.
Too bad some of us know which end of the screwdriver to use and not just for punching holes in oil cans.
Jim



Edited 2 time(s). Last edit at 03/01/2015 04:36PM by Jim Crank.

Lets go through the basics of steam and mechanics.

!) your filling a pool with water one with a 500 lbs of pressure 1 inch sqr area line, the other with 1 lbs of pressure and 500 sqr area line.
Which while fill faster and take less work energy, the low pressure big hose, as there is internal flow resistance in high pressure.

2) heat the same amount work energy to steam, one at 1 lbs of pre, the other to 500 lbs pre.
The lower as a good percentage heat, just will not be hot enough, to heat high pre. at all.

3 Heat loss 2 equal radiators are pressurized, Like the whole boiler, engine and condenser, 1 to 1 lbs pre. the other 500 lbs pre.
The radiator with high pressure has higher temperature and and atoms hitting the metal more, losing huge amounts of energy.

4) Parts friction a small bearing with 1 lbs force running 500 turns, or a very large bearing with 500 lbs of force turning just once.
This is no brainier, the light bearing will have little resistance even multiplied by 500 turns, the % loss on heavy bearing steals most of the energy.

5) Valve stress, 1 lbs on valve to open 500 times, compared to a valve has to fight 500 lbs just open ones.
All parts have to be bigger, again your dealing with friction, high pressures have high % of friction.

6) Reclaiming heat, hotter you heat water, the more the water turns into air.
This means adding more water high pressure, heating more cold water, means loss of heat!

This is simple as I can make it, if you do not understand, or better do not want to understand.
I can not help you.
I choose 40 to 50 lbs, because it a pressure, makes a good size small engine, in range that is easy to build for!

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