# Thread: Boiling Water Displacement Level?

1. Hello all.

I hope someone is kind enough to answer this question for me.

How do you measure the displacement of boiling water?

An example:
I have a container that is 5 inches high, 11 inches in circumference, and 3.5 inches in diameter. At what height of liquid H20 in the container may I safely bring the water to a boil and avoid the spilling of the liquid from the top of the container?

Additionally, if anyone knows a formula to repeat this calculation with containers of various sizes that would also be greatly appreciated.

Regards,

Daniel

2.

3. You can measure the volume increase of the water on going from room temperature to boiling point from the density of water at room temperature and 100 C. You can calculate the volume of steam produced from the latent heat of vaporisation, the energy input and for how long the energy input is on for. However, the main safety aspect will be due to splashing of boiling water from the bubbles breaking at the surface, there is no way I know of to calculate the amount of boiling water that will be splashed up from the surface or the height it will be splashed up to so I don't think you can calculate it exactly, it is chaotic and unpredictable (and will be different every time) you'll have to go with trial and error (stand back and be careful!).

I suppose if I put a good cover on it that will prevent water from escaping.

5. Careful though, if you use a cover that does not allow the boiled off water vapour to escape the pressure will build up and injury will be very likely!

6. The problem of "shrink and swell" is well known to those who design boiler level controls. I don't know how to calculate it though. I think it would be a fairly complicated function of the power level, the surface area of the heaters, and so forth.

Dynamic Shrink/Swell and Boiler Level Control - Practical Process Control by Control Guru

7. why turn something so simple Into a complicated mess, as stated mainly depends on how vigorsily its boiling.

8. Originally Posted by fizzlooney
as stated mainly depends on how vigorsily its boiling.
How do you measure how vigorously the water is boiling?

And how does that measurement help you "measure the displacement of boiling water"?

9. Originally Posted by Danieltravieso
Hello all.

I hope someone is kind enough to answer this question for me.

How do you measure the displacement of boiling water?

An example:
I have a container that is 5 inches high, 11 inches in circumference, and 3.5 inches in diameter. At what height of liquid H20 in the container may I safely bring the water to a boil and avoid the spilling of the liquid from the top of the container?

Additionally, if anyone knows a formula to repeat this calculation with containers of various sizes that would also be greatly appreciated.

Regards,

Daniel
The easiest way is probably weighing it liquid as it boils. If for example, it was a pot in a kitchen burner you could suspend the pot a grill being held on weights, or one weight and a pivot point on the other side.

10. Hello Daniel,

The easiest way

Hx = H/(1+delta T * beta)=5"/(1+80*0.00078) = 4.7"

delta T = 100 - 20 = 80

beta = 0.00078 - cubic temperature coefficient by 100 C degree

dagg11

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