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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
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de Laval turbine
Has anyone ever built a model of a de Laval turbine? I mean one with a real
de Laval nozzle, that put out some power. Or do you know of a good text about them? Most are either too simple or they're too abstract on the engineering theory side. I'd like to build a model of one, but not just a steam windmill. g I'd like to have some real de Laval nozzles on it. Thanks to any steamers who know about these motors. -- Ed Huntress |
#2
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de Laval turbine
On Mar 11, 1:22*am, "Ed Huntress" wrote:
Has anyone ever built a model of a de Laval turbine? I mean one with a real de Laval nozzle, that put out some power. Or do you know of a good text about them? Most are either too simple or they're too abstract on the engineering theory side. I'd like to build a model of one, but not just a steam windmill. g I'd like to have some real de Laval nozzles on it. Thanks to any steamers who know about these motors. -- Ed Huntress Maybe you can find a copy of: http://www.lib.ncsu.edu/findingaids/mss00090/#IDAVNIQ Some info he http://www.thespacerace.com/forum/in...p?topic=2595.0 Looks like the critical bit of science is the nozzle accelerates the steam jet to the speed of sound (and above? I assume speed of sound for the material being run through the throat) in the constriction, then the jet hits the divergent part of the nozzle and speeds up yet a bit further. Interesting stuff, and doubly cool since that principal is used in rocket nozzle design. So anything convergent-divergent is a de Laval nozzle. Sounds like you could test nozzle designs just by measuring the speed of the output jet (somehow!). I like the brief mention he http://www-istp.gsfc.nasa.gov/stargaze/Sgoddard.htm " Nowadays steam turbines are the preferred power source of electric power stations and large ships, although they usually have a different design--to make best use of the fast steam jet, De Laval's turbine had to run at an impractically high speed." An impractically high speed- that makes it a cool project right there! Dave |
#3
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de Laval turbine
On Mar 11, 1:22*am, "Ed Huntress" wrote:
Has anyone ever built a model of a de Laval turbine? I mean one with a real de Laval nozzle, that put out some power. Or do you know of a good text about them? Most are either too simple or they're too abstract on the engineering theory side. I'd like to build a model of one, but not just a steam windmill. g I'd like to have some real de Laval nozzles on it. Thanks to any steamers who know about these motors. -- Ed Huntress More good stuff, from astronomy sources of all places: http://www.absoluteastronomy.com/topics/De_Laval_nozzle http://www.mig.rssi.ru/mirrors/stern...arFAQ4.htm#q80 Dave |
#4
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de Laval turbine
On Mar 11, 8:08*am, wrote:
On Mar 11, 1:22*am, "Ed Huntress" wrote: Has anyone ever built a model of a de Laval turbine? I mean one with a real de Laval nozzle, that put out some power. Or do you know of a good text about them? Most are either too simple or they're too abstract on the engineering theory side. I'd like to build a model of one, but not just a steam windmill. g I'd like to have some real de Laval nozzles on it. Thanks to any steamers who know about these motors. -- Ed Huntress More good stuff, from astronomy sources of all places: http://www.absoluteastronomy.com/topics/De_Laval_nozzle http://www.mig.rssi.ru/mirrors/stern...arFAQ4.htm#q80 Dave Ed, At the following address is a very good little book on the design and manufacture of model steam turbines: http://ia311537.us.archive.org/2/ite...00harrrich.pdf Also Model Engineer magazine has had articles on this subject from time-to-time. Wolfgang |
#5
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de Laval turbine
--There are a couple of articles in Model Engineer, including some
clever ways of cutting the buckets. I messed around with 'em ages ago and wound up writing a little cnc program to make aeorfoil-shaped buckets and a steerable inlet jet; kinda fun. The rotor was no more than 1-1/2" dia tho.. -- "Steamboat Ed" Haas : Politics is a sinkhole for Hacking the Trailing Edge! : people without hobbies... www.nmpproducts.com ---Decks a-wash in a sea of words--- |
#6
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de Laval turbine
On Mar 10, 11:22*pm, "Ed Huntress" wrote:
Has anyone ever built a model of a de Laval turbine? I mean one with a real de Laval nozzle, that put out some power. Or do you know of a good text about them? Most are either too simple or they're too abstract on the engineering theory side. I'd like to build a model of one, but not just a steam windmill. g I'd like to have some real de Laval nozzles on it. Thanks to any steamers who know about these motors. -- Ed Huntress IIRC, Lindsay had some old reprints and archive.org had some stuff buried in their old steam power books. Some of the older books are lighter on the math and heavier on the practice, intended more for the guys that had to maintain them. The impulse turbine is kind of dead, the electric motor took over for running the stuff they used to use it for, haven't seen mention of them except as historical objects in any recent texts. When you shrink to model sizes, subtle curves in full- size practice start resembling straight lines anyway. Stan |
#7
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de Laval turbine
On Mar 11, 2:19*pm, wrote:
On Mar 10, 11:22*pm, "Ed Huntress" wrote: Has anyone ever built a model of a de Laval turbine? I mean one with a real de Laval nozzle, that put out some power. Or do you know of a good text about them? Most are either too simple or they're too abstract on the engineering theory side. I'd like to build a model of one, but not just a steam windmill. g I'd like to have some real de Laval nozzles on it. Thanks to any steamers who know about these motors. -- Ed Huntress IIRC, Lindsay had some old reprints and archive.org had some stuff buried in their old steam power books. *Some of the older books are lighter on the math and heavier on the practice, intended more for the guys that had to maintain them. *The impulse turbine is kind of dead, the electric motor took over for running the stuff they used to use it for, haven't seen mention of them except as historical objects in any recent texts. *When you shrink to model sizes, subtle curves in full- size practice start resembling straight lines anyway. Stan Yeah, but supersonic steam jet + rocket nozzles + linear equiv. speed of the rotor at about 1/2 the steam jet speed = lotsa fun! Where else are you going to get that much excitement with 1 moving part? Dave |
#8
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de Laval turbine
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#9
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de Laval turbine
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#10
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de Laval turbine
"Mark Rand" wrote in message ... On Wed, 11 Mar 2009 11:19:50 -0700 (PDT), wrote: The impulse turbine is kind of dead, the electric motor took over for running the stuff they used to use it for, haven't seen mention of them except as historical objects in any recent texts. GE turbines are/were impulse rather than reaction based for the HP and IP cylinders as were GEC in the UK and Alcatel-Alstom in France. That's something like 50% of the installed base in the world. Impulse turbines are certainly not kind of dead, I walked past two impulse rotors this afternoon in the erecting shop at work! Mark Rand RTFM I don't know about now, but I was under the impression that large steam turbines for years were hybrids, with one or two impulse stages followed by a series of reaction stages. -- Ed Huntress |
#12
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de Laval turbine
wrote in message ... On Mar 11, 1:22 am, "Ed Huntress" wrote: Has anyone ever built a model of a de Laval turbine? I mean one with a real de Laval nozzle, that put out some power. Or do you know of a good text about them? Most are either too simple or they're too abstract on the engineering theory side. I'd like to build a model of one, but not just a steam windmill. g I'd like to have some real de Laval nozzles on it. Thanks to any steamers who know about these motors. -- Ed Huntress Maybe you can find a copy of: http://www.lib.ncsu.edu/findingaids/mss00090/#IDAVNIQ Some info he http://www.thespacerace.com/forum/in...p?topic=2595.0 Looks like the critical bit of science is the nozzle accelerates the steam jet to the speed of sound (and above? I assume speed of sound for the material being run through the throat)... Right. Which is much higher than the speed of sound in the atmosphere. ...in the constriction, then the jet hits the divergent part of the nozzle and speeds up yet a bit further. I forget most of the dynamics, but it's pretty wild. Interesting stuff, and doubly cool since that principal is used in rocket nozzle design. So anything convergent-divergent is a de Laval nozzle. Sounds like you could test nozzle designs just by measuring the speed of the output jet (somehow!). Well, de Laval invented the thing (I think), so they use his name on it when it's applied to steam turbines. There are old engineering texts I've seen that provide formulas for all of the dimensions, based on steam temperature, superheat, pounds of steam produced, and so on. I like the brief mention he http://www-istp.gsfc.nasa.gov/stargaze/Sgoddard.htm " Nowadays steam turbines are the preferred power source of electric power stations and large ships, although they usually have a different design--to make best use of the fast steam jet, De Laval's turbine had to run at an impractically high speed." An impractically high speed- that makes it a cool project right there! Dave Even the little ones made for doing farm jobs, around the turn of the 20th century, turned at speeds around 30,000 rpm. I have no idea how they held together, given the state of metallurgy at that time. -- Ed Huntress |
#13
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de Laval turbine
wrote in message ... On Mar 11, 1:22 am, "Ed Huntress" wrote: Has anyone ever built a model of a de Laval turbine? I mean one with a real de Laval nozzle, that put out some power. Or do you know of a good text about them? Most are either too simple or they're too abstract on the engineering theory side. I'd like to build a model of one, but not just a steam windmill. g I'd like to have some real de Laval nozzles on it. Thanks to any steamers who know about these motors. -- Ed Huntress More good stuff, from astronomy sources of all places: http://www.absoluteastronomy.com/topics/De_Laval_nozzle http://www.mig.rssi.ru/mirrors/stern...arFAQ4.htm#q80 Dave Thanks, Dave. I'm collecting a good set of references here. I have them all saved for the next rainy weekend. -- Ed Huntress |
#14
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de Laval turbine
wrote in message ... On Mar 11, 8:08 am, wrote: On Mar 11, 1:22 am, "Ed Huntress" wrote: Has anyone ever built a model of a de Laval turbine? I mean one with a real de Laval nozzle, that put out some power. Or do you know of a good text about them? Most are either too simple or they're too abstract on the engineering theory side. I'd like to build a model of one, but not just a steam windmill. g I'd like to have some real de Laval nozzles on it. Thanks to any steamers who know about these motors. -- Ed Huntress More good stuff, from astronomy sources of all places: http://www.absoluteastronomy.com/topics/De_Laval_nozzle http://www.mig.rssi.ru/mirrors/stern...arFAQ4.htm#q80 Dave Ed, At the following address is a very good little book on the design and manufacture of model steam turbines: http://ia311537.us.archive.org/2/ite...00harrrich.pdf Also Model Engineer magazine has had articles on this subject from time-to-time. Wolfgang Great. Thanks, Wolfgang. -- Ed Huntress |
#15
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de Laval turbine
"steamer" wrote in message ... --There are a couple of articles in Model Engineer, including some clever ways of cutting the buckets. That's one of the things I most want to see. I don't have time to reinvent it all. I messed around with 'em ages ago and wound up writing a little cnc program to make aeorfoil-shaped buckets and a steerable inlet jet; kinda fun. The rotor was no more than 1-1/2" dia tho.. I'd like to make something around 6" diameter, if I can. Thanks, Ed. -- Ed Huntress |
#16
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de Laval turbine
wrote in message ... On Mar 10, 11:22 pm, "Ed Huntress" wrote: Has anyone ever built a model of a de Laval turbine? I mean one with a real de Laval nozzle, that put out some power. Or do you know of a good text about them? Most are either too simple or they're too abstract on the engineering theory side. I'd like to build a model of one, but not just a steam windmill. g I'd like to have some real de Laval nozzles on it. Thanks to any steamers who know about these motors. -- Ed Huntress IIRC, Lindsay had some old reprints and archive.org had some stuff buried in their old steam power books. Some of the older books are lighter on the math and heavier on the practice, intended more for the guys that had to maintain them. The impulse turbine is kind of dead, the electric motor took over for running the stuff they used to use it for, haven't seen mention of them except as historical objects in any recent texts. When you shrink to model sizes, subtle curves in full- size practice start resembling straight lines anyway. Stan I've tried plucking out information from old steam books, but they've generally been disappointing. There was one I saw years ago that analyzed some of de Laval's actual production models, and that was great. But I have no idea how to find it now. Anyway, it's one of those pursuits that's a good challenge, and I'd like to fool with it as I have time. -- Ed Huntress |
#17
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de Laval turbine
On Fri, 13 Mar 2009 16:42:57 -0400, "Ed Huntress"
wrote: "Mark Rand" wrote in message .. . On Wed, 11 Mar 2009 11:19:50 -0700 (PDT), wrote: The impulse turbine is kind of dead, the electric motor took over for running the stuff they used to use it for, haven't seen mention of them except as historical objects in any recent texts. GE turbines are/were impulse rather than reaction based for the HP and IP cylinders as were GEC in the UK and Alcatel-Alstom in France. That's something like 50% of the installed base in the world. Impulse turbines are certainly not kind of dead, I walked past two impulse rotors this afternoon in the erecting shop at work! Mark Rand RTFM I don't know about now, but I was under the impression that large steam turbines for years were hybrids, with one or two impulse stages followed by a series of reaction stages. It tends to be a graduation rather than completely one or the other. It tends to be more impulse at the HP end and more reaction at the LP end, but there are/were major differences in proportion. Causes problems when major companies merge, you don't always end up with an optimum design :-| The major difference in philosophy is that in an impulse design all the pressure drop is across the diaphragms (fixed stages). So you can make the rotor similar to a series of disks on a thinner shaft. This way, the interstage glands where all the pressure drop is (diaphragm to rotor) are shorter, due to being on a smaller diameter. The blade tip seals are far less significant doe to the token pressure drop across the moving stage. Because there's no pressure drop across the moving blades, there's no end-thrust issue. The disks even have (pressure) balance holes to ensure this. Reaction design turbines tend to be made with a barrel type rotor since the pressure drop across fixed and moving blades is similar, so you can't benefit from a shorter length of gland and you don't want a great big pneumatic piston effect generating end thrust on each stage. Obviously on a double flow cylinder, the end thrusts should balance. but on a single flow cylinder you've got problems. You can also play games like 100% impulse near the centre and 100% reaction near the tips for long blades. CFD is wonderful :-) regards Mark Rand RTFM |
#18
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de Laval turbine
"Mark Rand" wrote in message ... On Fri, 13 Mar 2009 16:42:57 -0400, "Ed Huntress" wrote: "Mark Rand" wrote in message . .. On Wed, 11 Mar 2009 11:19:50 -0700 (PDT), wrote: The impulse turbine is kind of dead, the electric motor took over for running the stuff they used to use it for, haven't seen mention of them except as historical objects in any recent texts. GE turbines are/were impulse rather than reaction based for the HP and IP cylinders as were GEC in the UK and Alcatel-Alstom in France. That's something like 50% of the installed base in the world. Impulse turbines are certainly not kind of dead, I walked past two impulse rotors this afternoon in the erecting shop at work! Mark Rand RTFM I don't know about now, but I was under the impression that large steam turbines for years were hybrids, with one or two impulse stages followed by a series of reaction stages. It tends to be a graduation rather than completely one or the other. It tends to be more impulse at the HP end and more reaction at the LP end, but there are/were major differences in proportion. Causes problems when major companies merge, you don't always end up with an optimum design :-| The major difference in philosophy is that in an impulse design all the pressure drop is across the diaphragms (fixed stages). So you can make the rotor similar to a series of disks on a thinner shaft. This way, the interstage glands where all the pressure drop is (diaphragm to rotor) are shorter, due to being on a smaller diameter. The blade tip seals are far less significant doe to the token pressure drop across the moving stage. Because there's no pressure drop across the moving blades, there's no end-thrust issue. The disks even have (pressure) balance holes to ensure this. Reaction design turbines tend to be made with a barrel type rotor since the pressure drop across fixed and moving blades is similar, so you can't benefit from a shorter length of gland and you don't want a great big pneumatic piston effect generating end thrust on each stage. Obviously on a double flow cylinder, the end thrusts should balance. but on a single flow cylinder you've got problems. You can also play games like 100% impulse near the centre and 100% reaction near the tips for long blades. CFD is wonderful :-) regards Mark Rand RTFM It sounds like more formulas and calculations than I would do for fun. d8-) 'Too bad Tesla's turbine didn't pan out the way he thought it would. It sure would make life simpler. -- Ed Huntress |
#19
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de Laval turbine
"Ed Huntress" wrote in message ... "Mark Rand" wrote in message ... On Wed, 11 Mar 2009 11:19:50 -0700 (PDT), wrote: The impulse turbine is kind of dead, the electric motor took over for running the stuff they used to use it for, haven't seen mention of them except as historical objects in any recent texts. GE turbines are/were impulse rather than reaction based for the HP and IP cylinders as were GEC in the UK and Alcatel-Alstom in France. That's something like 50% of the installed base in the world. Impulse turbines are certainly not kind of dead, I walked past two impulse rotors this afternoon in the erecting shop at work! Mark Rand RTFM I don't know about now, but I was under the impression that large steam turbines for years were hybrids, with one or two impulse stages followed by a series of reaction stages. -- Ed Huntress Not all! The old Canadian Pacific steamships Princess Marguerite, and Princess Patricia, had single stage impulse turbines. Steve R. |
#20
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de Laval turbine
Ed Huntress wrote:
That's one of the things I most want to see. I don't have time to reinvent it all. --Tellyawhat I'll take some photos today; somewhere I've got a little display I made that illustrates the steps required to machine a complete rotor. I'd like to make something around 6" diameter, if I can. --That's massive! IIRC the one Bill Lear made for his sand racer only had a 4" dia rotor and was rated over 100hp! -- "Steamboat Ed" Haas : Politics is a sinkhole for Hacking the Trailing Edge! : people without hobbies... www.nmpproducts.com ---Decks a-wash in a sea of words--- |
#21
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de Laval turbine
"steamer" wrote in message ... Ed Huntress wrote: That's one of the things I most want to see. I don't have time to reinvent it all. --Tellyawhat I'll take some photos today; somewhere I've got a little display I made that illustrates the steps required to machine a complete rotor. That's great, Ed. I'll bet a lot of people here would like to see that display. I'd like to make something around 6" diameter, if I can. --That's massive! IIRC the one Bill Lear made for his sand racer only had a 4" dia rotor and was rated over 100hp! Hmm. Maybe Lear had a reason to make it that small? I though the single-stage de Lavals were around 6" or 8" diameter and only produced a few horsepower. However, that was over 100 years ago. -- Ed Huntress |
#22
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de Laval turbine
On Mar 14, 5:34*pm, "Ed Huntress" wrote:
I'd like to make something around 6" diameter, if I can. --That's massive! IIRC the one Bill Lear made for his sand racer only had a 4" dia rotor and was rated over 100hp! Hmm. Maybe Lear had a reason to make it that small? I though the single-stage de Lavals were around 6" or 8" diameter and only produced a few horsepower. However, that was over 100 years ago. -- Ed Huntress IIRC for rocket nozzles you need to know the amount of gas first and the atmospheric pressure where it will be used, and then you design the nozzle. Dan |
#23
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de Laval turbine
On Mar 14, 3:13*pm, " wrote:
On Mar 14, 5:34*pm, "Ed Huntress" wrote: I'd like to make something around 6" diameter, if I can. --That's massive! IIRC the one Bill Lear made for his sand racer only had a 4" dia rotor and was rated over 100hp! Hmm. Maybe Lear had a reason to make it that small? I though the single-stage de Lavals were around 6" or 8" diameter and only produced a few horsepower. However, that was over 100 years ago. -- Ed Huntress IIRC for rocket nozzles you need to know the amount of gas first and the atmospheric pressure where it will be used, and then you design the nozzle. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Dan The little booklet I referred to above walks you step-by-step through the nozzle and rotor design for a model turbine. I build 1/16 scale models of locomotive steam turbo-generators, fully functional. At that small size, 5/8" rotor dia. and .025" nozzle throat one can take some liberties with the nozzle geometry. The rotor blades are not that forgiving, even in small sizes. I use the Terry turbine blade design which gives 180 deg flow return... very effective. The small turbine described will light up 4 flashlight bulbs @ 2.5 volts @ 1 amp @ 56,000 RPM, with 80 psig steam pressure. Increase the steam pressure and it will burn out the bulbs in a flash. A pressure regulator is necessary for unattended use on a steam locomotive. Wolfgang |
#24
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de Laval turbine
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#25
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de Laval turbine
On 15 Mar 2009 17:04:43 GMT, steamer wrote:
wrote: I build 1/16 scale models of locomotive steam turbo-generators, fully functional. --You have *got* to post some photos! :-) Agreed! That's been one of the big bugaboos to building a small steam launch - I wouldn't have any way to run the nav lights and the oil burner for the boiler. And while a double expansion auxiliary motor spinning a Car Alternator through a step-up gear would work... But it sounds like your turbine is aiming for 10W output, and the small boat would need more like 1KW to 2KW output - unless you've got a lot of excess capacity available, it might have to scale up one notch. -- Bruce -- |
#26
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de Laval turbine
On Mar 15, 3:47*pm, Bruce L. Bergman
wrote: On 15 Mar 2009 17:04:43 GMT, steamer wrote: wrote: I build 1/16 scale models of locomotive steam turbo-generators, fully functional. * *--You have *got* to post some photos! :-) Agreed! *That's been one of the big bugaboos to building a small steam launch - I wouldn't have any way to run the nav lights and the oil burner for the boiler. *And while a double expansion auxiliary motor spinning a Car Alternator through a step-up gear would work... * But it sounds like your turbine is aiming for 10W output, and the small boat would need more like 1KW to 2KW output - unless you've got a lot of excess capacity available, it might have to scale up one notch. * -- Bruce -- I shall make an effort to post some pics over the next little while. For electric power on a steam yacht I'd convert a 2 cylinder cast iron automotive air conditioning compressor into a steam engine -I did this for a friend- and run a good quality automotive alternator via a toothed belt, speeding up the drive by say 3:1. This would keep things quiet. Plans for this conversion were available in the popular do-it-yourself press in the late '70's or so. As to powering a model racing boat... It has been done. There is - another- little book available, but not on-line as far as I know, entitled Experimental Flash Steam. It covers the topic of steam powered racing boats using flash or monotube boilers with piston steam engines mostly; one experimenter did build a turbine powered boat. It is a fascinating book if you can find a copy, covering details such as feed, fuel, and oil pumps, and controls. I think that a 1 to 2 KW small steam turbine is doable especially if you don't need electric output or if it doesn't have to look "scale". My little turbine's output is primarily limited by the scale alternator... you can only squeeze so many turns of a certain sized wire into the available space; whereas the power can always be increased by increasing the number of steam nozzles until you have reached full admission ie. a full 360 deg. nozzle ring. Nothing to stop one from fitting, at the design stage, 30, 40, or 60 steam nozzles. The way I would approach it would be to design the steam nozzles as a full-admission nozzle ring and 3 or 4 pass terry turbine wheels as these are quite easy to make. With a small CNC mill even Laval (or was it Parson?) turbine wheels are not difficult to make. Turbines are a fascinating subset of the live steam hobby and I would encourage those interested to have a go. But read up on it first as there is no sense in re-inventing the wheel. Wolfgang |
#27
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de Laval turbine
On Wed, 11 Mar 2009 01:22:23 -0400, "Ed Huntress"
wrote: Has anyone ever built a model of a de Laval turbine? I mean one with a real de Laval nozzle, that put out some power. Or do you know of a good text about them? Most are either too simple or they're too abstract on the engineering theory side. I'd like to build a model of one, but not just a steam windmill. g I'd like to have some real de Laval nozzles on it. Thanks to any steamers who know about these motors. Ed, I'm not a steamer but have made quite a few de Laval nozzles in graphite, for small rocket motors. For motors under 1.5" diameter, the nozzles were (usually) formed using an ordinary 82 degree countersink for the entrance cone and a 29 degree cone-shaped carbide burr for the exit cone. They worked a treat. Rules of thumb for rocket motors operating at about 600-1000 psi (may have nothing whatever to do with steam): diameter of exit is about 2x diameter of nozzle throat; throat length is as short as is practical but should not exceed 1/2 the throat diameter; rounding off the sharp edges of the throat will improve performance. Hope this helps -- Terry "As a matter of fact, I *am* a rocket scientist... :-) |
#28
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de Laval turbine
"Terry" wrote in message news On Wed, 11 Mar 2009 01:22:23 -0400, "Ed Huntress" wrote: Has anyone ever built a model of a de Laval turbine? I mean one with a real de Laval nozzle, that put out some power. Or do you know of a good text about them? Most are either too simple or they're too abstract on the engineering theory side. I'd like to build a model of one, but not just a steam windmill. g I'd like to have some real de Laval nozzles on it. Thanks to any steamers who know about these motors. Ed, I'm not a steamer but have made quite a few de Laval nozzles in graphite, for small rocket motors. For motors under 1.5" diameter, the nozzles were (usually) formed using an ordinary 82 degree countersink for the entrance cone and a 29 degree cone-shaped carbide burr for the exit cone. They worked a treat. Rules of thumb for rocket motors operating at about 600-1000 psi (may have nothing whatever to do with steam): diameter of exit is about 2x diameter of nozzle throat; throat length is as short as is practical but should not exceed 1/2 the throat diameter; rounding off the sharp edges of the throat will improve performance. Hope this helps -- Terry "As a matter of fact, I *am* a rocket scientist... :-) It's a great help, Terry. The hard part of this, for me at least, has always been to get *practical* information, and every bit helps. Finally I'm accumulating some here. Now, all I need is time to put it to use. -- Ed Huntress |
#29
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de Laval turbine
On Wed, 11 Mar 2009 01:22:23 -0400, Ed Huntress wrote:
Has anyone ever built a model of a de Laval turbine? I mean one with a real de Laval nozzle, that put out some power. Or do you know of a good text about them? Most are either too simple or they're too abstract on the engineering theory side. Ed, I've uploaded a bunch of pages relative to turbines, 3 of which pages contain references to Model Engineer articles on building model turbines; they're at: http://www.box.net/shared/7fe502646h In ME No. 4320, 29 Feb.13 Mar 2008, is the second part of an article on a gauge 1 turbine loco pp.274-277. with some information on cutting the turbine blades. HTH, Mike in BC |
#30
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de Laval turbine
"Michael Gray" wrote in message news:AsQwl.17741$Db2.1307@edtnps83... On Wed, 11 Mar 2009 01:22:23 -0400, Ed Huntress wrote: Has anyone ever built a model of a de Laval turbine? I mean one with a real de Laval nozzle, that put out some power. Or do you know of a good text about them? Most are either too simple or they're too abstract on the engineering theory side. Ed, I've uploaded a bunch of pages relative to turbines, 3 of which pages contain references to Model Engineer articles on building model turbines; they're at: http://www.box.net/shared/7fe502646h In ME No. 4320, 29 Feb.13 Mar 2008, is the second part of an article on a gauge 1 turbine loco pp.274-277. with some information on cutting the turbine blades. HTH, Mike in BC Hey, thanks, Mike. They look great. Far be it from me to look a gift horse in the mouth, but for future reference, you might consider using the compressed TIFF format, rather than JPEG, when you want to reproduce a printed page. Because of the way the JPEG compression works, it makes the edges of letters (and any sharp edges) fuzzy, the fuzziness depending on how much you're compressing. TIFF doesn't do that, and you can save the space involved in reproducing color, if those settings are available to you. For an all-type page, or one with type and line drawings, you can use 2-bit compressed TIFF and usually you'll get a file that's both smaller than the equivalent JPEG, and much easier to read. It also prints much better. However, in this case, I can read those pages perfectly well. I'm going to take a close look this weekend. Thanks again. -- Ed Huntress |
#31
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de Laval turbine
On Fri, 20 Mar 2009 13:51:15 -0400, Ed Huntress wrote:
"Michael Gray" wrote in message news:AsQwl.17741$Db2.1307@edtnps83... On Wed, 11 Mar 2009 01:22:23 -0400, Ed Huntress wrote: Has anyone ever built a model of a de Laval turbine? I mean one with a real de Laval nozzle, that put out some power. Or do you know of a good text about them? Most are either too simple or they're too abstract on the engineering theory side. Ed, I've uploaded a bunch of pages relative to turbines, 3 of which pages contain references to Model Engineer articles on building model turbines; they're at: http://www.box.net/shared/7fe502646h In ME No. 4320, 29 Feb.13 Mar 2008, is the second part of an article on a gauge 1 turbine loco pp.274-277. with some information on cutting the turbine blades. HTH, Mike in BC Hey, thanks, Mike. They look great. Far be it from me to look a gift horse in the mouth, but for future reference, you might consider using the compressed TIFF format, rather than JPEG, when you want to reproduce a printed page. Because of the way the JPEG compression works, it makes the edges of letters (and any sharp edges) fuzzy, the fuzziness depending on how much you're compressing. TIFF doesn't do that, and you can save the space involved in reproducing color, if those settings are available to you. For an all-type page, or one with type and line drawings, you can use 2-bit compressed TIFF and usually you'll get a file that's both smaller than the equivalent JPEG, and much easier to read. It also prints much better. However, in this case, I can read those pages perfectly well. I'm going to take a close look this weekend. Thanks again. Thank you for the advice, don't worry I shan't get in a tiff about it. :-) Mike in BC |
#32
Posted to rec.crafts.metalworking
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de Laval turbine
"Michael Gray" wrote in message news:%qUwl.18901$PH1.10418@edtnps82... On Fri, 20 Mar 2009 13:51:15 -0400, Ed Huntress wrote: "Michael Gray" wrote in message news:AsQwl.17741$Db2.1307@edtnps83... On Wed, 11 Mar 2009 01:22:23 -0400, Ed Huntress wrote: Has anyone ever built a model of a de Laval turbine? I mean one with a real de Laval nozzle, that put out some power. Or do you know of a good text about them? Most are either too simple or they're too abstract on the engineering theory side. Ed, I've uploaded a bunch of pages relative to turbines, 3 of which pages contain references to Model Engineer articles on building model turbines; they're at: http://www.box.net/shared/7fe502646h In ME No. 4320, 29 Feb.13 Mar 2008, is the second part of an article on a gauge 1 turbine loco pp.274-277. with some information on cutting the turbine blades. HTH, Mike in BC Hey, thanks, Mike. They look great. Far be it from me to look a gift horse in the mouth, but for future reference, you might consider using the compressed TIFF format, rather than JPEG, when you want to reproduce a printed page. Because of the way the JPEG compression works, it makes the edges of letters (and any sharp edges) fuzzy, the fuzziness depending on how much you're compressing. TIFF doesn't do that, and you can save the space involved in reproducing color, if those settings are available to you. For an all-type page, or one with type and line drawings, you can use 2-bit compressed TIFF and usually you'll get a file that's both smaller than the equivalent JPEG, and much easier to read. It also prints much better. However, in this case, I can read those pages perfectly well. I'm going to take a close look this weekend. Thanks again. Thank you for the advice, don't worry I shan't get in a tiff about it. :-) Mike in BC Ugh... Well, it's strictly in the interest of better computing for all. d8-) -- Ed Huntress |
#33
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de Laval turbine
Thank you for the advice, don't worry I shan't get in a tiff about it. :-) Mike in BC Ugh... Well, it's strictly in the interest of better computing for all. d8-) Perhaps I should have put ("English humour") rather than a smiley face - I really do appreciate your telling me about the TIFF file compression. Or was your "Ugh" at the low level of my pun? Apologies offered. Mike |
#34
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de Laval turbine
"Michael Gray" wrote in message news:rtYwl.18934$PH1.16185@edtnps82... Thank you for the advice, don't worry I shan't get in a tiff about it. :-) Mike in BC Ugh... Well, it's strictly in the interest of better computing for all. d8-) Perhaps I should have put ("English humour") rather than a smiley face - I really do appreciate your telling me about the TIFF file compression. Or was your "Ugh" at the low level of my pun? Yes. g Apologies offered. Mike I'll get over it. Anyway, I'm looking forward to reading what you provided and learning more about these things. I saw a de Laval cream separator on my family's farm in New Hampshire over 50 years ago, and maybe I got fascinated by the name. But I'm impressed with the sophistication of de Laval's (and others') engineering on steam turbines in the late 19th century. They were really pushing the envelope. -- Ed Huntress |
#35
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de Laval turbine
Anyway, I'm looking forward to reading what you provided and learning more about these things. I saw a de Laval cream separator on my family's farm in New Hampshire over 50 years ago, and maybe I got fascinated by the name. But I'm impressed with the sophistication of de Laval's (and others') engineering on steam turbines in the late 19th century. They were really pushing the envelope. Ed, further to our correspondence, I've uploaded a spreadsheet listing of Model Engineer references to model steam turbines to: http://www.box.net/shared/mx1qds1uhc Now THAT should keep you busy for the weekend. Hope you have access to a library with old MEs. Mike in BC P.S. Why don't the present publishers, who seem to have a predilection for digital whatevers, put out a complete issue on CD as National Geographic have done? Any one who'd go for this at say about $100 or so for the first hundred years email: Sirs, it would be of great help to those of us who constantly have to reference back copies of Model Engineer, but who don't have ready access to those back copies, if you would consider issuing a set of CDs similar in nature to those issued by the National Geographic magazine i.e. 100 years of back issues for a little over $100. I am quite sure that I am not the only person who would welcome such an offer. There would still be a demand for "hardcopy" back issues for those who prefer them, but a fully searchable CD would be of inestimable value to the rest of us. yours sincerely, Michael Gray |
#36
Posted to rec.crafts.metalworking
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de Laval turbine
"Michael Gray" wrote in message news:1W9xl.18988$PH1.17553@edtnps82... Anyway, I'm looking forward to reading what you provided and learning more about these things. I saw a de Laval cream separator on my family's farm in New Hampshire over 50 years ago, and maybe I got fascinated by the name. But I'm impressed with the sophistication of de Laval's (and others') engineering on steam turbines in the late 19th century. They were really pushing the envelope. Ed, further to our correspondence, I've uploaded a spreadsheet listing of Model Engineer references to model steam turbines to: http://www.box.net/shared/mx1qds1uhc Now THAT should keep you busy for the weekend. Hope you have access to a library with old MEs. Mike, I don't think I responded to this old message, but thanks. There's half of my remaining lifetime of spare-time hobby study. g I'll work on that one for a while. -- Ed Huntress Mike in BC P.S. Why don't the present publishers, who seem to have a predilection for digital whatevers, put out a complete issue on CD as National Geographic have done? Any one who'd go for this at say about $100 or so for the first hundred years email: Sirs, it would be of great help to those of us who constantly have to reference back copies of Model Engineer, but who don't have ready access to those back copies, if you would consider issuing a set of CDs similar in nature to those issued by the National Geographic magazine i.e. 100 years of back issues for a little over $100. I am quite sure that I am not the only person who would welcome such an offer. There would still be a demand for "hardcopy" back issues for those who prefer them, but a fully searchable CD would be of inestimable value to the rest of us. yours sincerely, Michael Gray |
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