There WAS a step after Doble, and it was efficient. But WW2 prevented it.
Posted by Steam Captain
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Re: There WAS a step after Doble, and it was efficient. But WW2 prevented it. February 28, 2023 02:12PM |
Registered: 18 years ago Posts: 1,258 |
Hello Rick,
Well, I believe you are right insofar as the boilers need much more focus. That said it is still the boiler/engine combo that has to work together, and both need to be efficient.
Much of the improvements to IC engine technology have been to get them more efficient. This has also increased their power density to levels unimaginable in the forties and fifties. A friend of mine had an old Indie car that he took out for a drive now and then. He also had a Ford racing engine he would have given me. It was a 500 HP 252 ci I believe. That was fantastic power for that size of naturally aspired engine. The last I heard was that type of engine was putting out 700 HP.
So anyway an efficient engine and an efficient (high output) boiler (now generator) are needed for the LSR.
I did a calculation of the English car (it was really rough) and think it only got 140 HP out of that turbine. The car body was pretty streamlined. Remember Chuk's
car wasn't up to speed when it flipped. I think it was the soft salt that did it. Chuk's engineering and craftsmanship is just too good for that accident to be the fault of the car, or him.
Keeping the water turbulent inside the tubing is important, however, the bigger problem with heat transfer is with the combustion gasses to tubing interface. This needs turbulence and turbulence costs a pressure drop and this means a high pressure draft fan. Also an enhanced outer tube surface would be a great help but can be costly penny wise.
With a tightly curved tube as is found in smaller recirculating generators the water tends to spin against the inner surface because the column of traveling water is forced to go faster on the outside of the curve than the inside. The whole subject could use more experimental results though.
I have question about the units in the water conductivity chart. Are they supposed to be BTU/ft>2/ft/deg F ? If so, how did they set up the experiment?
Was it a cylinder of water 1 ft>2 in diameter and 1 ft long? You can do that with a solid but with a liquid there is convection too. I suppose one could stuff in a couple of rolls of toilet paper or paper towels to stop the convective part.
Anyway, that's enough for now. My cat is bothering me because she is stoned on catnip and wants something??????
Best Regards,
Bill G.
Well, I believe you are right insofar as the boilers need much more focus. That said it is still the boiler/engine combo that has to work together, and both need to be efficient.
Much of the improvements to IC engine technology have been to get them more efficient. This has also increased their power density to levels unimaginable in the forties and fifties. A friend of mine had an old Indie car that he took out for a drive now and then. He also had a Ford racing engine he would have given me. It was a 500 HP 252 ci I believe. That was fantastic power for that size of naturally aspired engine. The last I heard was that type of engine was putting out 700 HP.
So anyway an efficient engine and an efficient (high output) boiler (now generator) are needed for the LSR.
I did a calculation of the English car (it was really rough) and think it only got 140 HP out of that turbine. The car body was pretty streamlined. Remember Chuk's
car wasn't up to speed when it flipped. I think it was the soft salt that did it. Chuk's engineering and craftsmanship is just too good for that accident to be the fault of the car, or him.
Keeping the water turbulent inside the tubing is important, however, the bigger problem with heat transfer is with the combustion gasses to tubing interface. This needs turbulence and turbulence costs a pressure drop and this means a high pressure draft fan. Also an enhanced outer tube surface would be a great help but can be costly penny wise.
With a tightly curved tube as is found in smaller recirculating generators the water tends to spin against the inner surface because the column of traveling water is forced to go faster on the outside of the curve than the inside. The whole subject could use more experimental results though.
I have question about the units in the water conductivity chart. Are they supposed to be BTU/ft>2/ft/deg F ? If so, how did they set up the experiment?
Was it a cylinder of water 1 ft>2 in diameter and 1 ft long? You can do that with a solid but with a liquid there is convection too. I suppose one could stuff in a couple of rolls of toilet paper or paper towels to stop the convective part.
Anyway, that's enough for now. My cat is bothering me because she is stoned on catnip and wants something??????
Best Regards,
Bill G.
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Re: There WAS a step after Doble, and it was efficient. But WW2 prevented it. March 01, 2023 07:06AM |
Admin Registered: 17 years ago Posts: 2,031 |
The fan should not be a problem for an LSR car -- I have the solution right under the hood of my daily driver. As Jim Crank often noted, Doble solved the whole issue with their draft booster, which was a turbine driven by engine exhaust coupled to a blower. We have smaller, lighter, cheaper, and more efficient counterparts in the form of turbochargers -- I even recall that there is a modern turbo replacing the draft booster on some Doble.
If you wanted to keep the whole matter bare bones, you would just stick a port onto the car into which you could plug a backpack leaf blower and this would provide combustion air for the cold start. (Hey, it's Bonneville, every other car has some sort of starter cart). Once you had pressure up in the boiler, you would remove the leaf blower and start venting steam to the turbo to switch the burner to an internal source while you heat up the steam lines to the engine. Once you had the engine on line, you could cut the boiler vent line and let the engine exhaust drive the turbo.
Chuk and I have talked about the Bonneville accident and the causes are what you would expect if you've been through a number of accident briefings. There is rarely a specific, identifiable cause for an accident -- meaning that usually no one big thing is the problem. Instead, it is a number of small things that individually wouldn't look catastrophic ... but together add up to more than the sum of their parts. I think we can safely say that was what happened in this instance, it wasn't a critical failure but instead a cascade of little things that all came together at the wrong moment. The track conditions were certainly suboptimal and removing that factor alone would likely have led to a different outcome. One thing to keep in mind is that car was designed to incorporate a different powerplant, which failed to materialize. You can't just stick a radically different engine and boiler into something like an LSR machine which is literally designed around the system without invoking some compromises. This isn't a unique circumstance, you can research WW2 fighter plane development and literally find dozens of projects that foundered due to the replacement powerplants not performing in the same manner as those originally promised.
Regards,
Ken
If you wanted to keep the whole matter bare bones, you would just stick a port onto the car into which you could plug a backpack leaf blower and this would provide combustion air for the cold start. (Hey, it's Bonneville, every other car has some sort of starter cart). Once you had pressure up in the boiler, you would remove the leaf blower and start venting steam to the turbo to switch the burner to an internal source while you heat up the steam lines to the engine. Once you had the engine on line, you could cut the boiler vent line and let the engine exhaust drive the turbo.
Chuk and I have talked about the Bonneville accident and the causes are what you would expect if you've been through a number of accident briefings. There is rarely a specific, identifiable cause for an accident -- meaning that usually no one big thing is the problem. Instead, it is a number of small things that individually wouldn't look catastrophic ... but together add up to more than the sum of their parts. I think we can safely say that was what happened in this instance, it wasn't a critical failure but instead a cascade of little things that all came together at the wrong moment. The track conditions were certainly suboptimal and removing that factor alone would likely have led to a different outcome. One thing to keep in mind is that car was designed to incorporate a different powerplant, which failed to materialize. You can't just stick a radically different engine and boiler into something like an LSR machine which is literally designed around the system without invoking some compromises. This isn't a unique circumstance, you can research WW2 fighter plane development and literally find dozens of projects that foundered due to the replacement powerplants not performing in the same manner as those originally promised.
Regards,
Ken
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Re: There WAS a step after Doble, and it was efficient. But WW2 prevented it. March 01, 2023 12:18PM |
Registered: 6 years ago Posts: 725 |
Hi Bill,
The units on the water/steam conductivity chart are Btu/h ft *F. The h is enthalpy and comes from a steam table with SI units of joule/kg. Please don't ask to provide English or Imperial equivalent. Please keep a broader perspective on the image if you were to create the equation to calculate a steam generation rate with varying temperature, surface conductivity, pressure and density. I can sum it up as it is not easy.
Here is the takeaway from that post. The best way (my opinion) is seeing what values work best for other boiler/generator builders and estimate the generation rate. Yes, that is make an assumption and then build along with test it to see results. After seeing the model boat values, I picked up in the Flash Steam Book, my thought was how can this be achieved in larger scale. This led me to the fill concept that also was shown in the post earlier.
By-the-way, my two cats have me wrapped around their fingers.
Kind regards,
Rick
The units on the water/steam conductivity chart are Btu/h ft *F. The h is enthalpy and comes from a steam table with SI units of joule/kg. Please don't ask to provide English or Imperial equivalent. Please keep a broader perspective on the image if you were to create the equation to calculate a steam generation rate with varying temperature, surface conductivity, pressure and density. I can sum it up as it is not easy.
Here is the takeaway from that post. The best way (my opinion) is seeing what values work best for other boiler/generator builders and estimate the generation rate. Yes, that is make an assumption and then build along with test it to see results. After seeing the model boat values, I picked up in the Flash Steam Book, my thought was how can this be achieved in larger scale. This led me to the fill concept that also was shown in the post earlier.
By-the-way, my two cats have me wrapped around their fingers.
Kind regards,
Rick
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Re: There WAS a step after Doble, and it was efficient. But WW2 prevented it. March 01, 2023 04:38PM |
Registered: 18 years ago Posts: 1,258 |
Ken,
Did you know I was looking at fighter planes last night? I just love that Spitfire.
It amazes me just how fast the development of war machines was during WW2.
Hurrah for our side.
But now I wish the world leaders would have learned better from that war.
I was going to say more, but that would start a diatribe and I don't think I would want to listen to it, even if it's my own.
Bless You All,
Bill G.
Did you know I was looking at fighter planes last night? I just love that Spitfire.
It amazes me just how fast the development of war machines was during WW2.
Hurrah for our side.
But now I wish the world leaders would have learned better from that war.
I was going to say more, but that would start a diatribe and I don't think I would want to listen to it, even if it's my own.
Bless You All,
Bill G.
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Re: There WAS a step after Doble, and it was efficient. But WW2 prevented it. March 01, 2023 08:03PM |
Admin Registered: 17 years ago Posts: 2,031 |
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