How to calculate the leak rate based on pressure drop

[blinkz303]

TL;DR

I am currently working on a project trying to calculate leak rates from pressurised vessels filled with water.

I am currently working on a project trying to calculate leak rate and fluid loss from pressurised vessels filled with water over a time period of 30 minutes. So far I have used the Boyles Law which assumes that PV/T = constant which gets us P1 * V1 = P2 * V2 and PdV+VdP = 0 I formed this over to PdV=VdP. and divided by the change in time to get dV/dt = - VdP/Pdt

Could anyone help me and tell me if I am on the right track here or have I overlooked something.

 

[Chestermiller]

Is it liquid water or water vapor or are both present in the vessel. You need to establish the pressure drop vs flow rate relationship for the valve.

 

[blinkz303]

To clarify further: I am an intern at a company and I have been tasked with finding a method to calculate the leak rate and amount of fluid lost through possible cracks in a vessel. It can be assumed that the vessel is completely filled with water. I know the volume of the vessel and can figure out the hydrostatic pressure at the bottom of the vessel based on the volume. I have tried calculating the volume loss by calculating the change in the height of the water WH=P/rho*g
P being Pressure, rho being the density of water, g being the acceleration due to gravity.
I know the volume of water per meter of height and can therefore calculate the amount of water lost.
Would this be a viable method? I realized I am running into way to many problems using Boyle's law.

 

[Chestermiller]

To clarify further: I am an intern at a company and I have been tasked with finding a method to calculate the leak rate and amount of fluid lost through possible cracks in a vessel. It can be assumed that the vessel is completely filled with water. I know the volume of the vessel and can figure out the hydrostatic pressure at the bottom of the vessel based on the volume. I have tried calculating the volume loss by calculating the change in the height of the water WH=P/rho*g
P being Pressure, rho being the density of water, g being the acceleration due to gravity.
I know the volume of water per meter of height and can therefore calculate the amount of water lost.
Would this be a viable method? I realized I am running into way to many problems using Boyle's law.

Is there head space above the liquid water in the vessel? If so, what is in the head space, pure water vapor? Are the cracks exclusively on the bottom of the vessel, or are there cracks along the sides as well? how thick is the wall, and what are the approximate lengths of the cracks. Do you have any idea what the size of the crack openings are?

 

[Lnewqban]

I am currently working on a project trying to calculate leak rate and fluid loss from pressurised vessels filled with water over a time period of 30 minutes.

Welcome!

Please, see:
https://nts.com/ntsblog/pressure-ve...ion, or pressure,has been altered or repaired.

https://en.wikipedia.org/wiki/Hydrostatic_test