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Uniflow steamengine at 20% efficiency in a car project

Posted by wwilliam7 
Re: Uniflow steamengine at 20% efficiency in a car project
August 12, 2022 04:28AM
ok then i drop that ide sad smiley but what about my sec ide, to use a spray condenser with freezing water, stored in a 40L tank? engines exhaust will not only be cooled by the aircooled condensers but in sec stage the spray condenser.

i think i first build the engine so it runs nice after that i can play around with different condensing stuff to trying getting vacum down



Edited 1 time(s). Last edit at 08/12/2022 04:30AM by wwilliam7.
Re: Uniflow steamengine at 20% efficiency in a car project
August 12, 2022 07:19AM
There is no free lunch, the power it takes to pull a vacuum on the condenser to the engine takes more then the power you will gain from the engine.

Build a boat with a full-length keel condenser. You still will not pull a vacuum on the engine. You might think you will but the power to get the condensate out of the condenser and up to a hot well will take more then you gain. It’s cheaper to use the back pressure to push the condensate up to the hot well. No pumps. I did use a vacuum pump on my 35 foot boat though. What you gain after you take the water and oil from the condensate is clean water to go back into the boiler. You best be running some oil through your engine or else use a turbine.

I used ABS plastic sheets as a grid in my marine condenser when using steam cylinder oil. The oil sticks to it like a magnet. No oil floating on the other side of the condenser water.
Then Mobil SHC 634 Synthetic gear oil came along. Same ISO as steam cylinder oil 460
This oil separates from the water almost instantly, no need for filters or baffle plates.
You take the clean water from the bottom of the condensate tank back into the boiler.

All the power plants I have worked in, the condensates pumps use more power then any gain from the condenser, the idea is to keep any water out of the turbines.

Using Mobil SHC 634 on a condensing Stanley the condenser tubes stays nice and clean and doesn’t plug up. The oil goes back to the water tank and floats on top of the water, when you fill the water tank it runs out the over flow. You can use the oil absorbent blankets under the over flow and that will collect the oil or dump it into a bucket and pour the oil of the top. It still floats on top of the water.

Rolly
Re: Uniflow steamengine at 20% efficiency in a car project
August 12, 2022 08:58AM
The problem of using a tank of very cold water is that you need to first cool off the water. If you want to do that in the middle of the winter, that's fine, otherwise we are back to spending more energy on cooling the water than the power we get from the engine.

Anyhow, the idea won't work if you are travelling more than a very short distance.

It takes 180.07 BTU per pound of water to raise the temperature from 32 F to 212 F (or 0 to 100 Celsius). However, it takes 970.3 BTU to condense steam at 212 F into water at 212 F. So, it is going to take about 5-3/8 pounds or kilos of icy water to condense 1 pound or kilo of steam. Once condensed, the icy water is now hot and has no more cooling effect.

Ken
Re: Uniflow steamengine at 20% efficiency in a car project
August 13, 2022 07:45AM
Your idea for a spray condenser does have some merit. The technical name for the system is evaporation cooling effect. Also know as a swamp cooler like used in the MASH episodes, remember Hawkie Pierce. However, it would require some development in application.

I think you are on the right track to get an engine running with some type of boiler to supply the steam. A kind recommendation, your focus would be well spent on developing a boiler, steam generator, to power your engine. So many steam engine developers create this supper efficient engine and never see it run in a vehicle because it takes an astronomical amount of steam to make it run.

A steam engine comprises of a burner (heat source), boiler (steam generator) and engine (expander). The boiler will only produce steam based on the amount of heat received from the burner. The engine will only produce based on the amount of steam from the boiler. I think the logic is clear.

To get a system that works from a clean sheet design like you are considering is really challenging. It took me 9 years to get my steam scooter running. It is a clean sheet design and a simple non-condensing system. So much is involved like providing oil to the engine, working out the feed water pumps and check valves along with preheating the water with steam exhaust. Also, use the steam exhaust to draw the fire through your boiler.

You have so much to learn about steam engine design. Try building a steam bike to keep expenses down. Then build your car with lessons learned from the bike. Please try building and learn...keep us posted. smiling smiley

With kind regards,
Rick


Re: Uniflow steamengine at 20% efficiency in a car project
August 13, 2022 07:45AM
Your idea for a spray condenser does have some merit. The technical name for the system is evaporation cooling effect. Also know as a swamp cooler like used in the MASH episodes, remember Hawkie Pierce. However, it would require some development in application.

I think you are on the right track to get an engine running with some type of boiler to supply the steam. A kind recommendation, your focus would be well spent on developing a boiler, steam generator, to power your engine. So many steam engine developers create this supper efficient engine and never see it run in a vehicle because it takes an astronomical amount of steam to make it run.

A steam engine comprises of a burner (heat source), boiler (steam generator) and engine (expander). The boiler will only produce steam based on the amount of heat received from the burner. The engine will only produce based on the amount of steam from the boiler. I think the logic is clear.

To get a system that works from a clean sheet design like you are considering is really challenging. It took me 9 years to get my steam scooter running. It is a clean sheet design and a simple non-condensing system. So much is involved like providing oil to the engine, working out the feed water pumps and check valves along with preheating the water with steam exhaust. Also, use the steam exhaust to draw the fire through your boiler.

You have so much to learn about steam engine design. Try building a steam bike to keep expenses down. Then build your car with lessons learned from the bike. Please try building and learn...keep us posted. smiling smiley

With kind regards,
Rick


Re: Uniflow steamengine at 20% efficiency in a car project
August 16, 2022 02:43AM
Rick.H Wrote:
-------------------------------------------------------
> Your idea for a spray condenser does have some
> merit. The technical name for the system is
> evaporation cooling effect. Also know as a swamp
> cooler like used in the MASH episodes, remember
> Hawkie Pierce. However, it would require some
> development in application.
>
> I think you are on the right track to get an
> engine running with some type of boiler to supply
> the steam. A kind recommendation, your focus would
> be well spent on developing a boiler, steam
> generator, to power your engine. So many steam
> engine developers create this supper efficient
> engine and never see it run in a vehicle because
> it takes an astronomical amount of steam to make
> it run.
>
> A steam engine comprises of a burner (heat
> source), boiler (steam generator) and engine
> (expander). The boiler will only produce steam
> based on the amount of heat received from the
> burner. The engine will only produce based on the
> amount of steam from the boiler. I think the
> logic is clear.
>
> To get a system that works from a clean sheet
> design like you are considering is really
> challenging. It took me 9 years to get my steam
> scooter running. It is a clean sheet design and a
> simple non-condensing system. So much is involved
> like providing oil to the engine, working out the
> feed water pumps and check valves along with
> preheating the water with steam exhaust. Also,
> use the steam exhaust to draw the fire through
> your boiler.
>
> You have so much to learn about steam engine
> design. Try building a steam bike to keep
> expenses down. Then build your car with lessons
> learned from the bike. Please try building and
> learn...keep us posted. smiling smiley


ok so the spray condenser is practically impossible and the Ac pump system? sad smiley so the only way to go is a fan cooled condenser radiator? whick would give poor vacum? is it really that bad? with spray condenser, water does not have to be freezing tho, how much water for say 1h driving?
i try doin engine as simple as possible but still efficient, i can skip the condenser to begin with beginning with a double acting single cylinder, begining with the kawasaki VTX chopper engine crank , only using 1 connecting rod or both welded togheter and getting better bearing surface,
cylinder can be the original 104 in bore and 120mm stroke or modifying the 150mm piston on the rod? if so i get much more expanding possibilities, and can use less cutoff. the problem with a single double acting engine would be it only fires every 180 degrees witch would stall the car while driving, with a compaund and reciever o can connect LP cylinder so engine in all fires every 90 degres. but

beginning with this double acting semi uniflow cylinder would be the start. when it is working mounting it in a car and se and go from there until what will work out well, mayby using the vtx piston is the way to go, i think i can begin with a mecanical pump with sight glass, to the monotube boiler. it will have a steam drive halv full of water as described earlier. when water reach bottom, new water has to be pumped in.some type of temp sensor in bottom of the drum shutting of the fire when eraching critical low

i will use this opposit upside down mushroom car valve you guys showed me, for inlet and a tratitional exhaustvalve for the semi exhaust valve. nad even a semi exhaust valve
Re: Uniflow steamengine at 20% efficiency in a car project
August 16, 2022 05:49AM
Using cool water in a jet (spray) condenser is going to require a lot more cooling water than the amount of water that you will run through the boiler . Think how much water a non-condensing Stanley used and multiply that by 4 or 5.

Honestly, there is only one condensing system -- that I know of -- which has the potential to do what you want. This was built by John McCallum and Henry Percival Harvey Anderson. You can find a short description at

Holcroft-Anderson Locomotive

It is also described in US Patent Numbers: 1661900, 1688978, 1704441, 1982060

There are also European patents, but I find it far easier to download the nearly identical US patents via www.pat2pdf.org

Basically, McCallum and Anderson condensed part of the steam exhaust in a typical air-cooled condenser and the rest of the steam they recompressed to boiler pressure in a piston compressor. The piston compressor has the possibility of giving a good vacuum and they theorized that recompressing the exhaust steam recycled both latent and sensible heat into the boiler -- thereby saving more energy than it took to run the compressor. The condensed water was reinjected for thermodynamic reasons explained in the patents or by a quick study of air compressor theory.

A builder named Holcroft put the "Anderson" system into some locomotives and realized an efficiency boost. The systems were apparently trouble-prone, however. Some other researchers tested the idea and didn't find a large economy gain. It is possible that they implemented the system incorrectly. It is also possible that testing bias influenced the Holcroft locomotive. If you study production management you will find a research program very many years ago that tried to quantify how much changing the working environment improved productivity. They raised and lowered temperature, added better lighting and made lighting worse, and so on. No matter what they did, the efficiency improved. What happened was that people worked faster when they were being studied ... regardless of the environmental changes. I found something similar in Japan when assigned to evaluate the cranes and lifting gear in the shipyard. Every time I returned to the various shops on site, I found safety violations had disappeared. We eventually realized that the Japanese workers saw a US sailor in a hard hat with a camera and clipboard ... and assumed that I was looking for safety issues rather than studying the cranes... Anyhow, this sort of thing can affect testing -- perhaps the Anderson system really worked or perhaps the locomotive engineers knew that they were being watched and became much more diligent about shortening cutoff rather than simply throttling steam flow to the cylinders.. and maybe laid off the whistle a bit. Who knows?

Ken


.
Re: Uniflow steamengine at 20% efficiency in a car project
August 16, 2022 10:28AM
You may want to try a forced circulation generator with out the condenser at first. Very efficient proven design. (Cir 1874-1880) James B Herreshoff used in the Navy torpedo boats.
Size it to your needs. Actually my model would run your engine nicely.
Rolly


Re: Uniflow steamengine at 20% efficiency in a car project
August 17, 2022 05:39AM
Hey Rolly,

Beautiful model! This is one of the reasons I don't like the term "Lamont Boiler", this boiler was in service before he was born. Latta and Shawk were using the design before Herreshoff was born. It's hard to tell, but maybe Joshua Perkins was there even earlier yet. I like the fact that you simply refer to it as a forced circulation boiler -- that's honest.

Regards,

Ken
Re: Uniflow steamengine at 20% efficiency in a car project
August 18, 2022 04:51AM
Rolly Wrote:
-------------------------------------------------------
> You may want to try a forced circulation generator
> with out the condenser at first. Very efficient
> proven design. (Cir 1874-1880) James B Herreshoff
> used in the Navy torpedo boats.
> Size it to your needs. Actually my model would run
> your engine nicely.
> Rolly

cool but i dont really get it, the deisgn? is the monotub boiler sucking water from that halffilled drum? and then boil it in the steam generator connected directly to the engine? i was going to do the same, but use a steam drum after the steam generator, for wider buffert so steam can be collected for more different loads, straight monotube cant work with different loads , it need be fired after the load.

a steam drum has been used in all water tube boiler like in firetube boiler as that in the like stanley steamer. the sight glass as in pic give protection that water isnt to low. no sensors is needed, water can also be pumped in with mecanical piston pump for simplify the engine



Edited 3 time(s). Last edit at 08/18/2022 05:17AM by wwilliam7.


Re: Uniflow steamengine at 20% efficiency in a car project
August 18, 2022 05:26AM
Using cool water in a jet (spray) condenser is going to require a lot more cooling water than the amount of water that you will run through the boiler . Think how much water a non-condensing Stanley used and multiply that by 4 or 5.

Honestly, there is only one condensing system -- that I know of -- which has the potential to do what you want. This was built by John McCallum and Henry Percival Harvey Anderson. You can find a short description at

Holcroft-Anderson LocomotiveIt is also described in US Patent Numbers: 1661900, 1688978, 1704441, 1982060
There are also European patents, but I find it far easier to download the nearly identical US patents via www.pat2pdf.org

Basically, McCallum and Anderson condensed part of the steam exhaust in a typical air-cooled condenser and the rest of the steam they recompressed to boiler pressure in a piston compressor. The piston compressor has the possibility of giving a good vacuum and they theorized that recompressing the exhaust steam recycled both latent and sensible heat into the boiler -- thereby saving more energy than it took to run the compressor. The condensed water was reinjected for thermodynamic reasons explained in the patents or by a quick study of air compressor theory.

A builder named Holcroft put the "Anderson" system into some locomotives and realized an efficiency boost. The systems were apparently trouble-prone, however. Some other researchers tested the idea and didn't find a large economy gain. It is possible that they implemented the system incorrectly. It is also possible that testing bias influenced the Holcroft locomotive. If you study production management you will find a research program very many years ago that tried to quantify how much changing the working environment improved productivity. They raised and lowered temperature, added better lighting and made lighting worse, and so on. No matter what they did, the efficiency improved. What happened was that people worked faster when they were being studied ... regardless of the environmental changes. I found something similar in Japan when assigned to evaluate the cranes and lifting gear in the shipyard. Every time I returned to the various shops on site, I found safety violations had disappeared. We eventually realized that the Japanese workers saw a US sailor in a hard hat with a camera and clipboard ... and assumed that I was looking for safety issues rather than studying the cranes... Anyhow, this sort of thing can affect testing -- perhaps the Anderson system really worked or perhaps the locomotive engineers knew that they were being watched and became much more diligent about shortening cutoff rather than simply throttling steam flow to the cylinders.. and maybe laid off the whistle a bit. Who knows?


yes but you have to be in mind that stanly had poor efficiency mayby 5% thats 4 times more water wasted than a 18-20% efficient steam engine with a very low cutoff, especially with condenser. would be fun to know how much water has to be sprayed?

mayby firstly in stage 1: 2 big air condenser radiators, second: then going into the spray condenser? that would mayby work?
you mean a piston vacuum pump? mayby that would work, how much energy would this pump take from engine you think?

wouldn t this dual spray and radiator condensor work smiling smiley? with a 20% efficient steam engine? t he piston vacuum pump sounds complicated to build
Re: Uniflow steamengine at 20% efficiency in a car project
August 18, 2022 05:32AM
Your right, you really don’t get it.
It’s a forced circulation generator. The water going through the main tubing is being forced by the pump at a higher pressure, there are two pumps. One a feed pump the other a forced circulation pump. There is no steam space in the tubing, it’s only in the top of the drum. The water feeding the superheater is taken from the drum. This concept of forced circulation keeps the boundary layer of the tubing wet and under pressure for maximum heat transfer. The most efficient type of heat transfer.

Rolly
Re: Uniflow steamengine at 20% efficiency in a car project
August 18, 2022 06:35AM
William,

You really need to do the math before tossing out ideas. Let's suppose that you need 30 horsepower to maintain highway speeds. (You need a lot more power than that to accelerate up to speed and merge on the freeway --let's not forget hills-- but we'll assume that you can get by with just cruise horsepower).

Let's assume that you are pulling a really, really good 8 lbs/hp-hr steam rate. That's 240 pounds of steam per hour. If you want to use chilled water to condense that steam, let's say that you can get by with 4 pounds of chilled water per pound of steam exhausted from the engine (it will probably take more, but we'll give benefit of doubt). That comes out to 960 pounds per hour. One liter equals 2.2 pounds, so we divide 960 by 2.2 to get 436 liters per hour. Your 40 liters would last about 5-1/2 minutes.

I never said to use a vacuum pump to maintain a vacuum, that will never work because the amount of power to work the pump is more than you would gain from the engine. The Anderson system is a compressor that recycles steam, preserving the latent heat of vaporization, although some condenser is needed to avoid compression superheating. That said, you DO need a vacuum pump if you want to run a condenser down to a low vacuum -- onboard steam-driven ships we used two-stage, steam-driven air ejectors (jet pumps that have no moving parts). Condenser vacuum is created because a pound of water occupies far less volume than a pound of steam -- so, according to theory, when steam condenses there is a small amount of water and a lot of nothing else. That's theory. In the real world, the steam also contains air and other noncondensable gasses. This air is released when the steam condenses and builds up in the condenser -- this, in turn, increases condenser pressure unless we pump the air out. A steam car would need a proportionately bigger vacuum pump than an aircraft carrier because the carrier employs a DFT to store feedwater to the reactor. A DFT is a Deaerating Feed Tank and it performs three functions. 1. It stores feed water. 2. It preheats the feed water. 3. It removes air and other gasses from the feedwater. Even with a DFT, we needed vacuum pumps, without a DFT you need bigger pumps.

So, while the vacuum pump is not too big, because you are just removing air, it is still necessary.

If you think a vacuum pump sounds too complicated, you have to forget about building a low-pressure condenser.

Regards,

Ken



Regards,

Ken



Edited 2 time(s). Last edit at 08/18/2022 11:16AM by frustrated.
Re: Uniflow steamengine at 20% efficiency in a car project
August 18, 2022 08:06AM
A very brief lesson on boiling.

Note the image for pool boiling modes. The vertical scale is for heat flux, meaning the rate at which heat is transferred from the boiler tube to the water and/or steam. Note that the scale is in factors of ten, so the changes in value are much larger than would be assumed visually. The horizontal scale is the tube wall superheat temperature -- the amount by which the tube wall is hotter than the steam and water saturation temperature for a given pressure. While not as drastic as the vertical scale, it too is non-linear.

At low superheat, we get convective heat exchange, meaning the hot fluid rises and colder fluid fills its place. No steam is generated. Then we move to nucleate boiling as the superheat rises. At first, this occurs in the form of small steam bubbles, which provides moderate heat transfer. Greater superheat still provides nucleate boiling, but now it is in the form of slugs and columns -- the steam generation is fast enough that the steam doesn't break off into distinct bubbles. Heat transfer heads to a maximum. Then we reach Departure from Nucleate Boiling (DNB ). This occurs when the superheat temperature gets high enough that we reach transition boiling, which means that the sites producing steam bubbles are getting quite large and exist for unpredictable duration. Since steam is a poor heat conductor, and because the steam is now blocking the flow of water to the tube wall, the rate of heat transfer drops. We also call DNB the "Boiling Crisis" because this is where things start to go wrong. Once you pass DNB, it is possible to increase the tube temperature even if you reduce the burner firing rate, simply because the heat transfer rate has dropped so much. Eventually, the superheat temperature reaches the Leidenfrost point (see drawing).

We see the Leidenfrost Effect when we get a fry pan really hot on the stove and then sprinkle some water into the pan. Rather than immediately vaporizing, the water skitters back and forth and only evaporates slowly. This is because a layer of steam has formed between he water and the pan -- and the steam acts as an insulator to keep the water cooler. The water moves around rapidly because the steam film acts like a hovercraft or air hockey puck cushion of air. When Leidenfrost temperature is reached, the water no longer contacts the tube wall and heat transfer is at its lowest. Further temperature increase starts to increase heat transfer, but if we look at the temperature scale, we find that the temperature necessary is getting quite high. In fact, the temperature needed to reach the heat flux at DNB is far more than is needed to destroy the tube wall. This increase in heat flux occurs because radiation is now carrying heat rather than convection and natural steam bubble formation. It takes a fairly large temperature differential to radiate heat effectively so we try to avoid that when possible because we can do the same thing with much lower temperatures otherwise.

Finally, our last drawing shows the difference between high and low quality steam generation in a tube. Steam quality refers to the ratio of steam to water in the tube at any given point. High quality steam is quite dry, meaning little water is entrapped in the steam whereas low quality has a lot of water carried in the steam. The high quality steam flow produces an annular water film, meaning that water is in contact with the tube wall while steam flows down the center. So, an annular water film still provides decent heat flow through the tube. Low quality steam forms an inverted annular film, meaning that steam coats the tube wall while water flows down the center. Since steam is an insulator, the tube wall gets hotter until it burns out. Obviously, we want to avoid low-quality steam flow and inverted annular films. The way to do this is to provide high velocity flow, because the rapidly moving water creates turbulence which scrapes steam from the tube wall. We also want to keep an eye on the circulation ratio, which is the ratio of water to steam moving through the boiler. See last drawing. Note that the boiler should have a higher proportion of water to steam at lower pressure. This is because steam bubbles form more easily at lower pressure and we need more water to prevent steam film buildup. At normal steam car pressures, it is still desireable to have a high water to steam ratio. Although a lot of steam cars used monotube boilers, their circulation ratio of 1:1 is much lower than recommended at those pressures and we are therefore limited as to how much steam we can produce for the boiler size. The ratio of 1:1 is only recommended at and above supercritical pressure because, at that point, there is no formation of steam as we know it.

So, the key to a good high performance boiler is to keep a higher proportion of water to steam (by weight, the steam volume will likely be higher). Then, circulate the water rapidly. Watch that you do not reach DNB temperatures.



Edited 1 time(s). Last edit at 08/18/2022 09:25AM by frustrated.


Re: Uniflow steamengine at 20% efficiency in a car project
August 19, 2022 07:00AM
avgasrör is a vent pipe from an engine. In your design, it is a vent pipe from the boiler.

I re-attached the mono-tube concept. This is actually a good idea. I will show the Richard Smith boiler for a bike and will talk about the design. Plans are available at the SACA Website for a decent fee. Store Room, Steam Automobile

I recommend getting plans and following them to get good results. Or get the plans like I did to study the way it works. Then you can design your own mono-tube. It is a propane fired boiler that regulates the burner on and off with a thermo-expansion tube. It is a wound coil within a wound coil. It is 1/4 inch black iron pipe, schedule 40 wound with a specific spacing between the coil to allow the proper hot gas flow through it.

I very nice and kind gentleman named Jerry Oliver did just that and built a beautiful steam motorcycle. Some pictures are attached of the Richard Smith mono-tube boiler.

I also included a mono-tube forced circulation design using an injector. I provided this concept as food for thought. Hope that this inspires you to build something along these lines. Kind regards, Rick


Re: Uniflow steamengine at 20% efficiency in a car project
August 28, 2022 03:24PM
t-hank everyone ive read all you guys wrote i will answer you smiling smiley this is my concept boiler, very easy, the monotube pipe is a 30-40mm exhaust pipe much easier to bend when the monotube coil is much wider, boiler about 1-5 meter wide is my plan.

-The monotube boiler in the middle is hollow with a drum, the coil pack is between 2 drums if you understand, this forces the heat throught all the coil pack from up to down or the reverse when the wood is on fire,

-Boiler is flexi fuel it burn all type of oil with a oil burner as in the stanlys, , which is beneficialat start , at same time you start engine , oil/ ethanol is sprayed with a button activated from the ignition in pos 3 (start) on the wood in the firebox preparing it to fast catch fire after some min, the wood is put in at the same time from inside car in a pipe. after some min when pressure is up, and the wood can be fired up with a spark from a button, this car i think is the first in modern history burning with both wood and oil flexi fuel smiling smiley all old steam cars was only fired with expensive fuel. if this work it will be total free fuel for my car, making it able go around europ for free with alot of wood, the firebox will have a waterheat sensor being connected to the originalwater temp heater gauge in the car, then i know the fire is lit.

i want to do it as simple as possible to make it. the big pipes will hold much more water and take som more min to be fired up i know that. but will only mayby be10-20 turns in coil with a pipe jack i need to buy, instead of 100s of turns bended, i also have plans for a compressed air to start driving before pressure is up.

im struggeling if the ide building 2 double acting engine instead would be the better, with less efficiency skipping the LP cylinder. then i can skip the differential to, 1 engine on each wheel making it possible fire every 90 degrees making it much smoother to drive, without deadcenters at start/stops, but the problem is the slideablev camshaft now in this case need 2 shaft activated separate of eachother, it would be impossible.



Edited 3 time(s). Last edit at 08/29/2022 07:18AM by wwilliam7.


Re: Uniflow steamengine at 20% efficiency in a car project
August 28, 2022 05:12PM
I still have to note that in many places it is illegal to have a car without a differential. That's for good reasons, too -- separately driven wheels won't automatically divide torque properly. I'd check on local laws before continuing in that direction. Even if legal, the car is probably not going to be as safe to drive.
Re: Uniflow steamengine at 20% efficiency in a car project
August 28, 2022 06:12PM
its not illigal in sweden thou
Re: Uniflow steamengine at 20% efficiency in a car project
August 29, 2022 07:07AM
you are right o g0 for the differential
Re: Uniflow steamengine at 20% efficiency in a car project
August 29, 2022 07:21AM
Rolly Wrote:
-------------------------------------------------------
> Your right, you really don’t get it.
> It’s a forced circulation generator. The water
> going through the main tubing is being forced by
> the pump at a higher pressure, there are two
> pumps. One a feed pump the other a forced
> circulation pump. There is no steam space in the
> tubing, it’s only in the top of the drum. The
> water feeding the superheater is taken from the
> drum. This concept of forced circulation keeps the
> boundary layer of the tubing wet and under
> pressure for maximum heat transfer. The most
> efficient type of heat transfer.
>
yes all monotube force the water from the bottom i know that, couse they are forced cirkulatoin generators.
> Rolly
Re: Uniflow steamengine at 20% efficiency in a car project
August 29, 2022 07:24AM
frustrated Wrote:
-------------------------------------------------------
> William, You really need to do the math before tossing out
> ideas. Let's suppose that you need 30 horsepower
> to maintain highway speeds. (You need a lot more
> power than that to accelerate up to speed and
> merge on the freeway --let's not forget hills--
> but we'll assume that you can get by with just
> cruise horsepower).
>
> Let's assume that you are pulling a really, really
> good 8 lbs/hp-hr steam rate. That's 240 pounds of
> steam per hour. If you want to use chilled water
> to condense that steam, let's say that you can get
> by with 4 pounds of chilled water per pound of
> steam exhausted from the engine (it will probably
> take more, but we'll give benefit of doubt). That
> comes out to 960 pounds per hour. One liter
> equals 2.2 pounds, so we divide 960 by 2.2 to get
> 436 liters per hour. Your 40 liters would last
> about 5-1/2 minutes.
>
> I never said to use a vacuum pump to maintain a
> vacuum, that will never work because the amount of
> power to work the pump is more than you would gain
> from the engine. The Anderson system is a
> compressor that recycles steam, preserving the
> latent heat of vaporization, although some
> condenser is needed to avoid compression
> superheating. That said, you DO need a vacuum pump
> if you want to run a condenser down to a low
> vacuum -- onboard steam-driven ships we used
> two-stage, steam-driven air ejectors (jet pumps
> that have no moving parts). Condenser vacuum is
> created because a pound of water occupies far less
> volume than a pound of steam -- so, according to
> theory, when steam condenses there is a small
> amount of water and a lot of nothing else. That's
> theory. In the real world, the steam also
> contains air and other noncondensable gasses. This
> air is released when the steam condenses and
> builds up in the condenser -- this, in turn,
> increases condenser pressure unless we pump the
> air out. A steam car would need a proportionately
> bigger vacuum pump than an aircraft carrier
> because the carrier employs a DFT to store
> feedwater to the reactor. A DFT is a Deaerating
> Feed Tank and it performs three functions. 1. It
> stores feed water. 2. It preheats the feed water.
> 3. It removes air and other gasses from the
> feedwater. Even with a DFT, we needed vacuum
> pumps, without a DFT you need bigger pumps.
>
> So, while the vacuum pump is not too big, because
> you are just removing air, it is still necessary.
>
> If you think a vacuum pump sounds too complicated,
> you have to forget about building a low-pressure
> condenser.


i understand o go for the traditional cooling radiators with fans, i can add some smaller spray condenser to to that, but the most importent as said is to first build the engine
Re: Uniflow steamengine at 20% efficiency in a car project
August 29, 2022 07:28AM
frustrated Wrote:
-------------------------------------------------------
"> A very brief lesson on boiling.
>
> Note the image for pool boiling modes. The
> vertical scale is for heat flux, meaning the rate
..."


thank for the informationsmiling smiley, i wont use superheat it only ruins the lubrication and is not needed in a high efficient uniflow engine, becaouse of the thermodynamical good cyckle. i gonno build the boiler as simple as possible with bended exhaust pipe 30-40 mm wide. check my latest post.



Edited 1 time(s). Last edit at 08/29/2022 07:28AM by wwilliam7.
Re: Uniflow steamengine at 20% efficiency in a car project
August 29, 2022 09:16AM
William,

You can't design an effective automobile if you don't do the proper math.

Yes, uniflow engines can be more efficient than counterflow engines when both are using saturated steam. Better does not equal good, however. All heat engines are limited by the Carnot Cycle, meaning that efficiency improves as the difference between the highest and lowest temperatures of the working fluid inside the cycle increases. Since we can't make things much cooler for a number of practical reasons, we have to go hotter to be efficient. Please see Jay Carter, Peter Barrett, Dutcher Industries, and everyone who tried to build a high-efficiency steam car in the 70s.

Please show me an example of a working steam car that achieved higher economy with saturated steam -- other than the Doble-Detroit. Abner Doble designed a boiler that burns out easily -- because he ignored every single thing that I wrote about up above. He also "improved" the Joy valve gear and ended up with an engine that couldn't decide whether it ran forward or backwards. He put oil in the water to simplify lubrication -- and it clogged the condenser. Meanwhile, he wrote articles and advertisements claiming it was one of the greatest cars ever built. He has no credibility with that machine.

As for the boiling information not being important, you can talk to Abner Doble about that. As just noted, that boiler tended to burn out -- a lot. It was also a saturated steam boiler. The basic laws of heat transfer state that you can only transfer heat from a hotter substance to a cooler substance. If the boiler water is at boiling temperature, the boiler tube has to be hotter than boiling temperature. Therefore, you can indeed experience DNB and inverted annular film flow.

By definition, you cannot expand saturated steam even the slightest amount without some of the steam condensing into water. Given the vast difference in volume between equal masses of steam and water, we see that condensation causes pressure to drop dramatically. Of course, we need pressure to make power.

Attached find two graphs for exactly the same uniflow engine, the sole difference being that one is operating at 1,000 degrees F while the other is at 544.7, which is a tiny fraction of a degree above saturation. The engine using superheated steam gets far better efficiency. The saturated steam engine is a little more powerful because saturated steam is heavier and you get more steam into the cylinder at cutoff -- which is not a good thing.

Note, I had two change the graphs -- I had the spreadsheet saved on the cloud and it wasn't updating the graphs in real time.



Edited 3 time(s). Last edit at 08/30/2022 05:27AM by frustrated.


Re: Uniflow steamengine at 20% efficiency in a car project
August 29, 2022 10:23AM
No, No. A mono tube generator is not a forced circulation generator. The end of the mono tube in where the steam is generated when the throttle is opened. Almost all Doble and White mono tube generators burned out that section of the mono tube where the water gave up the heat as steam.

The forced circulation generator has at least two pumps or more. A feed pump to a drum and one or more forced circulation pumps keeping the water in the circulation coil at a higher pressure then the drum, marinating a wet boundary layer in the coil all the time, no steam in the coil. Heat transfer only.

The supper heater coils come off the drum. The pressure drops slightly in the drum when the throttle is opened but not in the forced circulation coil maintained at a higher pressure by it’s own pump.

Rolly
Re: Uniflow steamengine at 20% efficiency in a car project
August 29, 2022 10:53AM
Rolly is right.

Circulation is defined as "Movement through a circle or circuit".

A monotube steam generator is a "once through" device -- fluid starts at one end and steam comes out the other. It cannot have circulation because the flow is not in a circle or a circuit.

Ken
Re: Uniflow steamengine at 20% efficiency in a car project
August 30, 2022 03:54AM
Having no differential is not a problem, I have driven my 1925 French Salmson car 70,000 miles since restoring it in 1985. It has a relatively narrow track and a single solid 40mm axle shaft connecting the wheels - works very well although with skinny tyres is probably better than it would be with more grip.

The problem in Williams case is the independent drive to the wheels of the two engines which would certainly do strange things to the steering.

Mike



Edited 1 time(s). Last edit at 09/01/2022 03:15AM by Mike Clark.
Re: Uniflow steamengine at 20% efficiency in a car project
September 04, 2022 05:54AM
you mean like this smiling smiley ??



Edited 1 time(s). Last edit at 09/04/2022 06:39PM by wwilliam7.


Re: Uniflow steamengine at 20% efficiency in a car project
September 05, 2022 04:31AM
You got it. Just add a supper heater coil between the drum and the engine.

Rolly
Re: Uniflow steamengine at 20% efficiency in a car project
September 05, 2022 07:16PM
The attached concept is something I've been working on for another fellow. It shows the superheater as Rolly says. I agree with Rolly on adding a superheater.

This concept is designed to be used with the other attached concept, feed water heater. The idea is to heat the water as much as possible before inducing into the boiler drum. I'm actually considering application on my steam car build.

One unique concept is to incorporate a check valve in the boiler drum. When not feeding water, the boiler naturally circulates. When one feeds water; by closing the bypass valve, it drives the water through the generating tubes in a multi-path process.

Also, when not feeding water into the boiler drum, the feed water circulates through the economizer tubes and heats the hot tank. This way the heat is always being captured and utilized.

Note that I just got confirmation that the flash tube I show works to maintain the boiler pressure w/out cooling down the boiler.

Rick


Re: Uniflow steamengine at 20% efficiency in a car project
September 07, 2022 11:03AM
Interesting design Rick.
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Uniflow steam engine färdig skiss på motorn.jpg 466.9 KB open | download wwilliam7 05/24/2022 Read message
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