how to calculate the force created by liquid thermal expansion

[MrMax99]

Can anyone tell me how to calculate the force created by liquid thermal expansion? (equations would be nice )

 

[dcasto]

why not think about it and we'll give you clues.

Things expand when they get warm. We use the term Thermal expansion. research this for liquids, you might even peek at gases too.

So with that, you'll need to understand compressibility, can you say compressibility. We use bulk modulus sometimes to mean compressibility of liquids. look it up.

Now, mass balance. If we put a fixed mass in the container, it must always be there right? But when we heat it up, the mass expands, so same mas larger volume, what happens, I'll give you this equation

density = Mass/volume

so we can compress the liquid by adding pressure. see whats next.....

 

[Unotec]

One more hint, depending on the liquid, it might be considered incompressible

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[dcasto]

undet unotec's scerio, then the forces are infinite, a warm breath on the pipe and it'll blow up!

 

[Unotec]

Only if there is no room to expand, as in my gaden hose's pipe this last winter. If the vessel where the liquid is contained does not expand at the same rate and has a moving part, like a piston, it might move it. Unless the restriction to move is greater than the strength of the vessel walls.

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[MrMax99]

I think my question was misunderstood. If I have a liquid (lets say mercury) in a 1x1x2 container filled up half way and I put something on top of the mercury as the temperature rises a given amount, with how much force will the mercury push this object and how high?

 

[mbeychok]

MrMax99;

Is the container open at the top? Or is it a closed container with vapor space filled with air or some other gas?

Milton Beychok
(Visit me at www.air-dispersion.com)
.

 

[MrMax99]

It is open at the top.

| |
|_____| (this line can slide up)
|.........|
|.........| (the ... is liquid)
-----------

 

[JoeTank]

The pressure exerted on the piston (plus any added weight) will never be more than the weight of the piston divided by the area. It's simple statics. The force exteded on the pistion = piston weight plus any weight added to the piston. I am assuming zero resistance to piston movement due to a sealing mechanism.

Joe Tank

 

[Unotec]

Fe de erratas on my last post... water expands when it FREEZES!! But well, the effect is similar.
MrMax99, if you read Joe's and Dcasto's comments you have your answer. Both for actual and potential forces. You should be able to deduce anything else you might need from here.

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>