How the engine in submarines work?

Question

How the engine in submarines work?

Answer 1

While the answer given is mostly correct, only one thing is incorrect.

Nuclear powered submarines are very quiet, and are not as noisy as their predecessors.

Answer 2

In "conventional" subs, they work on battery power when submerged and diesel on the surface. The diesel charges the battery when its on top. Nuclear subs make steam that drives a turbine.

Answer 3

Depends on what kind of sub's your talking about.  I'll guess your talking about Military.

Their are 2 types, Diesel and Nuclear.  

The Diesel Subs ***No longer used by the United States.*** Use a diesel engine for running on the surface and charging battery packs.  Then they go to battery's underwater ***No place for exhause when underwater.***  Their benefits are they're quieter then nuclear.  But they can't stay underwater to long, and they're speed underwater is slow.

The Nuclear boys use Reactors to superheat water withing the reactor which is converted to steam which runs a turbine that powers the sub.  The benefit of this is they can remain underwater pretty much indefendentley.  The reactor also removes carbon dioxide and puts out clean oxygen, so even the crew can breath without worrying about exhailing.  They're not as quiet as Diesel's, but unlimited range and high speed make then the standard in the sub world.

Update. - Diesel Sub's when on the surface running with their engines are not quiet at all.  But when running on batteries underwater they are/were quieter then the last generation of Nuclear Subs.  The new class of Nuclear Boys are quieter and much more stealthy then the older L.A. Class of attack subs.  So drunkmunkey25' is right, I wasn't thinking about the new generations of submarines.

The folowing is a Copy/Paste from Wikipedia.org, who's link is posted in the "Know you source?"

While the greater endurance and performance from nuclear reactors mean that nuclear submarines are better for long distance missions or the protection of a carrier battle-force, conventional diesel-electric submarines have continued to be produced by both nuclear and non-nuclear powers, as they can be made stealthier, except when required to run the diesel engine to recharge the ship's battery. Technological advances in sound dampening, noise isolation and cancellation have substantially eroded this advantage. Though far less capable regarding speed and weapons payload, conventional submarines are also cheaper to build. The introduction of air-independent propulsion boats led to increased sales numbers of such types of submarines.

Answer 4

When you talk submarine propulsion, the issue of noise tends to come up.  Since most submarine technology centers around military use, staying unobserved is critical to a submarines 'success'.  A military submarine that can be detected is the equivalent of a half sunk surface ship.  

The first answer is very good.  The two traditional alternatives are diesel/battery and nuclear.  Diesel/battery runs on diesel on the surface and runs for short periods on stored battery energy.  Nuclear can run as long as they have food, oxygen, and water for the crew.  

Compared to running on batteries, a nuclear power plant is RELATIVELY noisy.  The boiling water in a nuclear power plant does make noise on certain frequencies.  Of course, nuclear engines are much quieter than when a diesel electric recharges.  

There are other options propulsion options which have come up recently in AIP (Air Independant Propulsion).  Closed circuit diesels, diesel engines adapted to run with captive gasses, have pretty much reached the limit of usefullness due to the inherent noise when running an internal combustion engine.  Submarines running Sterling engines have shown to be feasible, but also have noise problems.  The most promising non-nuclear alternative uses PEM (hydrogen) fuel cells to run electric motors.  Once a method of storing hydrogen cheaply and reliably becomes available, this technology will take off.  Combined with sonic "shielding" and magnetically neutral materials, these submarines are a viable alternative to nuclear submarines albeit only for short periods of time being submerged.  

Propulsion is only a part of the energy equation for submarines.  The air scrubbers, which are required to keep the crew breathing, need power too.  In a nuclear submarine, this is not a problem since there is more than enough power.  With AIP (Air Independent Propulsion) submarines, powering the airhandling equipment is what limits the time they can be submerged.

Answer 5

Normal, on surface: Battery power when submerged!