5 replies to this topic

[panoska]

Hello everyone,

 

I am interested in the case of liquid movement scenario. By liquid movement, I mean the continuous flow out of thank, which causes vacuum. Hence in breathing of air is required. 

 

 

I found somewhere that the equation to calculate the amount of in-breathing equivalent air flow is:

 

Vair = Vliquid,outlet * sqrt(ρair / ρnormal)

 

where 

Vair is the normal volumetric flowrate of air equivalent for in breathing in Nm3/h

Vliquid, outlet is the volumetric flowrate of the liquid from the tank in m3/h

ρair is the density of air at the temperature of air in kg/m3

ρnormal is the density at normal conditions in kg/m3

 

My question is how to derive the above equation?

 

 

(I looked in API 2000, but the formula to calculate the air equivalent is much more complicated.)

 

 

 

 

 

[breizh]

Hi,

For low pressure tank API 2000 is the reference. 

I found "somewhere" is not the appropriate language for an engineer. What the issue with "complicated" formula?

Consider the annexes in the document attached and forget about shortcut.

Use the search engine in this forum:

Relieving Flow Rate In Terms Of Air Equivalent - Relief Devices Forum - Cheresources.com Community

 

You may also want googling Graham's law.

 

Breizh.

Attached Files

•  API 2000 7th EditionBallot 2013 edition.pdf   4.94MB   7 downloads

[panoska]

Thanks Breizh,I will check the graham law and the discussion in the forum.

I said "somewhere", because I could not find the source!

[SamThaGangsta]

Thanks Breizh,I will check the graham law and the discussion in the forum.

I said "somewhere", because I could not find the source!

How could you utilize the source if you don't have the source? I'm just yanking your chain, but seriously, whenever you use an equation or source in the course of your work you should have it noted or saved somewhere to refer to. Good luck on your problem, I would be interested to hear about what you find!

[panoska]

There is a plethora of sources in google. It can be that you remember WHAT you read, but you cannot remember WHERE you found it.

[Dacs]

Follow API 2000.