Non-piston steam engines

[IanN]

Hi,

There was a series of 21 articles published in Model Engineer magazine (issues 4588 - 4628, 7th June 2018 to 20th Dec 2019) by Mike Tilby which described the history, the theory and (rather depressingly) the physics/thermodynamics explaining why “model” turbines cannot deliver useful power
There was a design for a turbine published by E T Westbury in ME magazine start in issue 2778 (some time in 1954)

Ian

 

[Mechanicboy]

Hi,

There was a series of 21 articles published in Model Engineer magazine (issues 4588 - 4628, 7th June 2018 to 20th Dec 2019) by Mike Tilby which described the history, the theory and (rather depressingly) the physics/thermodynamics explaining why “model” turbines cannot deliver useful power

Ian

Ian..

See at the movie of the model train powered by Wada works model steam turbine, there is enough power to run model train with wagons.

 

[Richard Hed]

Ian..

See at the movie of the model train powered by Wada works model steam turbine, there is enough power to run model train with wagons.



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Do you know ;if it is possible to get plans for this turbine? The cut-away doesn't look too difficult to make.

 

[Mechanicboy]

Do you know ;if it is possible to get plans for this turbine? The cut-away doesn't look too difficult to make.

There is not plan for this Wada Works steam turbine, but you can see how to design and build own steam turbine in this link http://www.machinemuseum.nl/model/model_stoomturbine.pdf

 

[goldstar31]

As a rather precocious 14 year old school boy, I built Corporal Henwood's ram jet engine from Aeromodeller magazine. It was the time of Frank Whittle and 'Doodle bug' Flying Bombs.
My efforts were similar

So what about seeing if Hero's Aeolipile can be made to work. It is much vaunted by classical scholars but my guess is that as it is described is only a pretty toy.
However, oddly, the name in steam turbines 'erupts. I was born and bred where Charles Algernon Parsons built and tested his models which eventually becaime a huge engineering works on Tyneside.
His Turbinia was something that I regularly visited during my lunch hours from school in Newcastle.
Look it up, it's quite fascinating

 

[Steamchick]

No plan available, it's my own design of the gear house with propeller shaft except the turbine. The reduction gear has a reduction ratio at 1:10. It has 4 gearwheel of hardened steel (gearwheel from EGR valve in Peugeot Boxer) in a bit SAE 20 oil bath in the gear house.

I has maked the steam turbine after the drawning of Elmer Verburg steamturbine with ball bearing.

Then i took the test with difference oils in the bearings.

Here are the tests of oils and measured revolutions per minute:
Work pressure= Mobil ESP 5W-30 / Air tool oil / Diesel oil (fuel for diesel engine as lubricant)

1 bar= 4700 / 13230 / 17600
1.5 bar= 6200 / 17900 / 25700
2 bar= 11400 / 21660 / 31500
2.5 bar= 15500/26340 / 36700
3 bar= 18600 / 28800 / 41800

The ball bearing get less friction with diesel oil as lucricant, it is sensitive for jet stream from nozzle. With high revolution above 15000 rpm, I can feel there are enough torque when trying to stop the turbine shaft. With heavy turbine wheel will give better torque in high revolution (saved energy in the flywheel with other..).

With less friction means less waste of the steam and fuel for heating the boiler.

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Very interesting study of oils. Much appreciated, as this sort of information doesn't exist anywhere I have looked. I am aware of the lubrication qualities of DERV - because the fuel pumps need lubrication from the fuel there is a specified "lubricity" value stated by diesel engine manufacturers e.g. Renault - for first fill. Otherwise (e.g. central heating fuel, etc.) similar fuels would damage the pumps when used. -0 One reason paraffin oils knacker diesel engines.
K

 

[tornitore45]

I even resort to putting a piece of kitchen bench (a sink cutout) on top of my vise to get some work space.

Same Idea here. But... one day I climbed and stepped on that nice surface with the intention to clean he AC filter.
The "tray" was not tight in the vise and fell miserably backward on the air compressor.

 

[Richard Hed]

There is not plan for this Wada Works steam turbine, but you can see how to design and build own steam turbine in this link http://www.machinemuseum.nl/model/model_stoomturbine.pdf

Thank you, that will be a beginning for sure.

 

[Steamchick]

On Turbines.. A friend used a Hard Drive fr the discs for his Tesla design model. Works well - but fast. But watching on the internet, I have only ever found one video that showed a Tesla Turbine reaching true speed. It worked OK up to around 70,000rpm, then suddenly took off up to over 120,000rpm as the true friction drag of the steam on the surface of the discs really started to work. Apparently the efficiency of his turbine was based on the ratio of diameters from the outer (entry point of steam) to exhaust diameter, as the steam is travelling at near disc surface speed, which in turn depends on the radius at any particular speed. And when you get the high speed efficiency, there isn't much "wasted" steam. Unlike some....
https://uk.video.search.yahoo.com/y...=4f951d7b3ec2a09c168a16542ee65624&action=view
So for Tesla, from a 10" diameter (perimeter) down to a 1 1/2" diameter exhaust gave nearly 85% efficiency.... whereas the Parsons type of turbine can only achieve 50%theoretical efficiency per stage. But Parsons - being a simply sort of chap - just looked at the triple and quadruple expansion engines of the time and said he should build a multi-stage turbine.... thus gaining a bit more efficiency at each additional stage. Hence all the major power stations and aircraft follow his principles, not Tesla's, The reaction turbine shown by Jens is very nice, but you can buy a small version of this from China for about £50~£70. Although that is not the point, but making your own that works is the reason we all enjoy this thread. Nice one Jens! I'll try and find a design I can send you as I have more than a few squirrelled away... There is one design, similar to yours, but with cross-flow steam where the exhaust from one phase passes down a passage to a second, then third then fourth stage, making the single rotor a multi-stage turbine. Each steam jet is angled at 45 degrees to the axis, and the reflected" steam passes down a collector zone and around a reversing passage to come back at 45 degrees to the rotor on the opposite side. (Model Steam Turbines: H.H. Harrison: fig.68).
https://www.amazon.co.uk/H.-H.-Harrison/e/B001KII30K/ref=ntt_dp_epwbk_0Clever, and suitable for model boats I believe? Practically, I understand "Boat people" commonly use flash boilers when powering turbines, as they are "power-motivated" people. How about you Jens? We haven't seen your boiler and boat yet. "An engine is but an ornament unless it is allowed to live and do some work. (or was the quotation "Man" instead of "engine"?).
A post-script on that clever chap Parsons. A university study analysed the efficiency of his drive and a hull shape, and decided that his long, narrow, planing, hull had more to do with his top speed than the power input. - Makes him a clever boat designer as well as salesman!
Look-up "Consuta" to see another fast boat - but this time driven by a reciprocating engine.
http://www.consuta.org.uk/workshop/Home.htmlUnique as it is the first real composite hull. - Pre-polyester resins and fibreglass! But a fast craft for its period.
And "Thanks Richard" for an inspired first message to start this thread!

 

[Richard Hed]

On Turbines.. A friend used a Hard Drive fr the discs for his Tesla design model. Works well - but fast. But watching on the internet, I have only ever found one video that showed a Tesla Turbine reaching true speed. It worked OK up to around 70,000rpm, then suddenly took off up to over 120,000rpm as the true friction drag of the steam on the surface of the discs really started to work. Apparently the efficiency of his turbine was based on the ratio of diameters from the outer (entry point of steam) to exhaust diameter, as the steam is travelling at near disc surface speed, which in turn depends on the radius at any particular speed. And when you get the high speed efficiency, there isn't much "wasted" steam. Unlike some....
https://uk.video.search.yahoo.com/y...=4f951d7b3ec2a09c168a16542ee65624&action=view
So for Tesla, from a 10" diameter (perimeter) down to a 1 1/2" diameter exhaust gave nearly 85% efficiency.... whereas the Parsons type of turbine can only achieve 50%theoretical efficiency per stage. But Parsons - being a simply sort of chap - just looked at the triple and quadruple expansion engines of the time and said he should build a multi-stage turbine.... thus gaining a bit more efficiency at each additional stage. Hence all the major power stations and aircraft follow his principles, not Tesla's, The reaction turbine shown by Jens is very nice, but you can buy a small version of this from China for about £50~£70. Although that is not the point, but making your own that works is the reason we all enjoy this thread. Nice one Jens! I'll try and find a design I can send you as I have more than a few squirrelled away... There is one design, similar to yours, but with cross-flow steam where the exhaust from one phase passes down a passage to a second, then third then fourth stage, making the single rotor a multi-stage turbine. Each steam jet is angled at 45 degrees to the axis, and the reflected" steam passes down a collector zone and around a reversing passage to come back at 45 degrees to the rotor on the opposite side. (Model Steam Turbines: H.H. Harrison: fig.68).
https://www.amazon.co.uk/H.-H.-Harrison/e/B001KII30K/ref=ntt_dp_epwbk_0Clever, and suitable for model boats I believe? Practically, I understand "Boat people" commonly use flash boilers when powering turbines, as they are "power-motivated" people. How about you Jens? We haven't seen your boiler and boat yet. "An engine is but an ornament unless it is allowed to live and do some work. (or was the quotation "Man" instead of "engine"?).
A post-script on that clever chap Parsons. A university study analysed the efficiency of his drive and a hull shape, and decided that his long, narrow, planing, hull had more to do with his top speed than the power input. - Makes him a clever boat designer as well as salesman!
Look-up "Consuta" to see another fast boat - but this time driven by a reciprocating engine.
http://www.consuta.org.uk/workshop/Home.htmlUnique as it is the first real composite hull. - Pre-polyester resins and fibreglass! But a fast craft for its period.
And "Thanks Richard" for an inspired first message to start this thread!

Really, "it's My pleasure" (spoken with an upper class English snob accent). Another Item I am interested in is the "roots blower"--this is an item that is used a lot in industry for vacuuming up large amounts of goo and also for pressure blowers into the air of larger (like trucks) diesel engines. I started one, but couldn't at the time get any machinable cast iron. I could just as easily use steel, aluminum or brass (or even uranium ) or any other cheap metal. Just reverse the flow (and a few modifications to make it better) of air and yuou have an engine! The really cool thing about these is the low number of parts! Two end caps, a body, two double lobed "pistons", a shaft, two gears--that's all. An engineer friend of mine says they are very powerful.

there are other types of engines too. does anyone have any more ideas?

Whoops--that's two shafts and four bearings.

 

[vederstein]

Any heat engine has the purpose of converting stored chemical energy into kinetic (mechanical) energy. Often this is then transferred to electrical energy.

If you remember Carnot, heat engines have a theoretical maximum efficiency based the temperature difference between two temperature reservoirs. Actual efficiencies are always less than this theoretical maximum. Gasoline engines are about 25% thermally efficient. Coal burning power plants are around 35% efficient. Some highly optimized diesel engines are approaching 50% efficient. A steam locomotive was about 5% efficient. Watt's condensing engine was about 1-3% efficient.

Other than a battery, If a method to convert chemical energy into electricity exists bypassing the heat stage, the energy conversion could be much more efficient.

Does anyone know the conversion efficiencies of fuel cells?

...Ved.

 

[Mechanicboy]

How about you Jens? We haven't seen your boiler and boat yet. "An engine is but an ornament unless it is allowed to live and do some work. (or was the quotation "Man" instead of "engine"?).

I have not acquired a boat or made a new boat yet. This steam turbine with reduction gear is not designed for high speed and is intended for model cargo / cruise ships with realistic speed. With propeller shaft revolution from my steam turbine is much like a one cylinder Stuart 10V with the same propeller (I have Stuart D-10). The torque out of propeller shaft is strong enough.

 

[Steamchick]

Thanks Jens. I like your ambition, but I'll be very interested to see the final boat performing, and hear your comments on how much heat (gas?) It takes to run. I found with my boats with recipient engines that as I was at L.P. 20 to 30 psi, the addition of a condenser really made a big difference to performance. Also, using the condensate to feed the boiler increased 8 minutes "on the pond" to more than 20.... The gas tank limit for that boat.
Like you, I am fascinated by engines, but the whole system "from fire to wash/ wake" is just as fascinating. Most people seem to just apply overkill to make a working boat. One guy at our club had a total loss exhaust and a reservoir of 3 litres to provide water for the boiler.... A lovely model, just not "engineered". His steam plant was huge for boat. My steam plants seem huge, but I have a 3 in (7.5cm.) dia boiler with almost 3/4" (2cm) thick casing and insulation, so it looks huge at 4 1/2" dia in a 5" wide hull. The space was there so I filled it for efficiency! Also, I am always dismayed when I see un-insulated steam pipes in finished models. Wrapped string, painted with white emulsion paint, is an easy finish that improves performance and looks (IMHO) compared to polished copper pipework. I'm sure you'll do an excellent engine room. I look forward to your future posts and pictures.
On your engine.... have you considered drilling radially in the root of each slot, then axially with exhaust drillings, to channel the exhaust steam more towards the centre of the turbine for collection to an exhaust pipe? Then the sides of the turbine space could be close to the blades? It may Increase torque (I have no idea?). It is a simple reaction turbine, of which I have no experience! Maybe for reaction turbines you need good nozzle shape and the minimum exhaust back--pressure? (Who knows?).
Well done, on an interesting engine project. It is showing lots of promise!
K2

 

[Mechanicboy]

I found the movie of the chinese build steam turbine uner testing .. works well..