In takeing the risk that I will give Ross Roland ideas has anyone ever heard about or considered putting a turbo charger on a steam locomotive. Exhaust steam from the pistons would turn the turbo wich would blow air onto the fire.

Oh, Boy!...

That 'waste energy' from the exhaust is already being used for that purpose. A proper exhaust nozzle and stack setup, with the smokebox properly sealed, will pull a vacuum through the flues and tubes, and will pull combustion air up through the grates and firebed.

It has been like that for, what, almost two hundred years? No need to re-invent the wheel; all this would do is add complexity, while the present system works well. Now, there are overfire jets, applied above the fire, on some of the most modern steam, but they were for another purpose: smoke abatement.

Steamships have been built with forced draft, using a steam turbine, electric motor, or sometimes even a diesel to power a blower, but that requires a sealed fireroom, which becomes under pressure. This would be pretty hard to do on a steam locomotive.

Another downside to this 'turbocharging' scheme has to do with cinders and fly ash. Just what do you think cinders, from a coal burner at least, will do to the blades on the hot side of the turbo? The Union Pacific tried burning pulverized coal as an experiment on a gas turbine-electric. It's biggest claim to fame was it's habit of throwing loose eroded away turbine blades through the turbine casing and sides of the carbody.

Time to leave well enough alone...

I wish we had a laugh button. Ha ! Ha !

That turbo might not do too great with an oil burner, either, once you sand out the tubes....

Jos Koopmans has written the definitive book abut the design of highly efficient exhaust systems, which combined with using the steam not necessary for drafting for feedwater heating and steam jacketing on cylinders, would provide a lot more reliable efficiency than a turbocharger.

Well, it wouldn't exactly be a turbocharger, but I think that maybe you could gain something by using some kind of blower to feed more air to an oil fire. I say this because I've worked on several oil burners that breathed fire out the dampers and firedoor when they were working hard. I suppose you could force air into these openings so that the last bit of unburned gases wouldn't have to go looking for it. (And you could still sand the tubes through the usual peep hole.)

What I don't know is, if this would save more energy than it uses. I WILL say is that the harder you work an oil burner, the faster it'll make steam, until something let's go...

The relatively few condensing steam locomotives which were built essentially worked this way- steam exhausted from the cylinders turned a turbine which powered an exhaust blower which drew air through the fire and then combustion gases through the boiler and out the stack.

The best known examples are the 25C 4-8-4's of the South African Railways.

In the case of the 25C's, it took a lot of R&D to make exhaust blowers that would survive in the harsh smokebox environment as the blades are subjected to a constant stream of very abrasive cinders.

Hello,

As an addendum to Hugh's comments, there are a few YouTube videos of Class 25Cs in operation. The one particular video of a 25C traveling upgrade has it producing a volcanic eruption of black smoke. You wonder if the exhaust turbine for the draft fan was at a fixed proportion or could have throttled or boosted steam flow to lean out the cumbustion. Obviously the fan speed tracked the exhaust rate but maybe they were over firing.

Regardless it was an interesting design. With (90) 25Cs built it was certainly more than an experiment and certainly the SAR fielded the concept in mass. Their complexity doomed them as (87) were converted to non-condensing. It's good that (2) survived with the condensing gear.

Cheers!

Randy

The French Velox boiler locomotive was converted from a 4-6-0 in 1937 is sort of what you are talking about. It has a steam generator type boiler in which the combustion chamber is under 35 psi air pressure supplied by a compressor that is powered by a gas turbine using the combustion exhaust from the steam generator and a steam turbine fed live steam from the generator. The rest of the steam generator output goes to the 4 cylinder compound locomotive.
http://www.douglas-self.com/MUSEUM/LOCO ... /velox.htm

Some of the early B&O geared locomotives had turbans to increase draft. See: http://www.douglas-self.com/MUSEUM/LOCO ... k/jack.htm . The Tom Thumb lost the race with a horse because the draft turban failed.

Keep in mind that a 'turbocharger' is not any kind of draft device. The Velox locomotive mentioned (or any other design using a positive-pressure firebox) comes closer to the idea. But in an external-combustion cycle, where the pressure of the combustion gas does not have a physical proportional concordance with the developed cylinder horsepower, we have to look elsewhere.

One interesting idea was Sharpe's idea of turborecompression, using the energy in a large volume of exhaust steam to recompress IP steam in a compound-engine configuration. There were earlier approaches; Gotaverken in Sweden had a famous one. These have much more use on ships, where there is plenty of space for the piping and auxiliaries and other paraphernalia to make the trick work. And for each of these things with even a shred of thermodynamic validity, there are plenty of cranks who have not a clue how steam works but design fancy ways to 'go turbo'.