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allthesamepieman t1_j29fe4i wrote

Reply to comment by dittybopper_05H in Just back from witnessing a test firing of a rocket motor that my neighbor built by goatharper

An engine is a specific type of motor but not all motors are engines. Engines are thermal devices -- they convert heat energy into motion. You could build a steam engine that doesn't require air but it would still be an engine because it uses the heat expansion of water to create a motive force.

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dittybopper_05H t1_j29l3z9 wrote

>You could build a steam engine that doesn't require air but it would still be an engine because it uses the heat expansion of water to create a motive force.

We have them today. It's called a "nuclear power plant". No one I know calls it a "nuclear engine", or a "nuclear motor", for that matter. Even when they are used for propulsive power (like for submarines and aircraft carriers).

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allthesamepieman t1_j29m4ji wrote

That's because the nuclear part only generates the heat, it doesn't provide the motive force. A steam turbine is the motor but we don't call a steam turbine an engine either even though we could. Nuclear power is used to generate electricity which in turn powers electric motors. That's why we don't call them nuclear motors or engines. We do have some nuclear detonation propulsion engines though but they have a whole host of other problems.

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dittybopper_05H t1_j2ags41 wrote

>Nuclear power is used to generate electricity which in turn powers electric motors.

Not always. Often, a PWR (pressurized water reactor) is used with a closed loop of superheated water that turns water into steam in a heat exchanger in order to directly drive propulsive turbines which are geared directly to the screws.

For example, the USS Tullibee was the first US submarine to use turbo-electric drive like you're thinking of, all of the other nuclear submarines before it used direct drive.

And almost all of the submarines afterwards. The Los Angeles class, for example, has the turbines connected physically to the screw, as does the current Virginia class subs (connected physically to the pumpjet).

In fact, I don't think the US has any nuclear powered ships that use turbo-electric propulsion. I know the Royal Navy does, though.

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allthesamepieman t1_j2avlhx wrote

Very cool, I didn't know that. So do we call those steam engines or nuclear motors?

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Yippeethemagician t1_j29md3i wrote

And the amazing thing is since we're just boiling water to create steam, there are so many better options besides nuclear.

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how_tall_is_imhotep t1_j2aj0du wrote

There is no connection whatsoever between the two parts of that sentence. There are reasonable arguments against nuclear power, but “it just boils water” isn’t one of them.

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Yippeethemagician t1_j2brv7a wrote

Yes it is. Because alot of people incorrectly believe that there is something magical about nuclear power. It just boils water. That waste stays for a long time, in the thousands of years. They aren't able to deal with it now, and I don't see anyone being able to deal with it later. Hangout at a nuke plant sometime. Be amazed and horrified with how much the Simpsons got right.

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how_tall_is_imhotep t1_j2bu1di wrote

I’m not at all surprised that you get all of your knowledge of nuclear power from the Simpsons. That explains why you think that nuclear plants boiling water is some kind of secret that no one knows about (on the Simpsons, the cooling towers emit some kind of noxious smoke).

But no, real nuke plants are not like that. Please don’t talk as if you’ve been to one.

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Yippeethemagician t1_j2bua8m wrote

It's not a well known secret, but enough people are surprised to find this out. And yeah, it's just not something that can be "greenwashed"

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dittybopper_05H t1_j2af5l2 wrote

That depends on the application. For some applications, nuclear reactors are the best option.

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Yippeethemagician t1_j2bs4n0 wrote

In absolutely limited applications. Just making them to make power for residential consumption? It's a bad idea. The waste is out there, and it's real.

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Chiknlitesnchrome t1_j29oxij wrote

What is water made of

H2O

O-oxygen

Steam engines need air

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allthesamepieman t1_j29pqzj wrote

Just because an element is part of a molecule doesn't make it a part of something else. Air is mostly nitrogen, not oxygen. You can't breathe pure water vapor, it's not air. Internal combustion engines cannot burn water vapor. If you can figure out how to burn water you'll be a billionaire and save the planet.

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