Pipeline Pressure Calculation - Help please

[rainmaster00]

Was just looking for some help on how to calculate the pressure in a pipeline at a particular location. Consider the attached image for example. How would I calculate the pressure at the green arrow?? Any help would be appreciated. Thanks

 

[bimr]

The pressure is equal to the pressure at the pipeline entrance plus 10 m static fluid head minus the frictional loss through the pipeline. The pressure will dissipate as it enters a tank that is open to the atmosphere.

 

[rainmaster00]

Thanks for getting back to me. Is there any way I could calculate the pressure at that point if I knew the point was located say 5 metres from the tank inlet?

 

[katmar]

It all depends on whether you know what the flow rate is. If you know the flow rate and if the tank on the right side of your sketch is open to the atmosphere then it does not matter too much what happens upstream (i.e. on the left side of the sketch) and it is easier to work from the known pressure on the right hand side (i.e. atmospheric) and work towards the green arrow. The pressure at the green arrow will be the 2m of water column plus the losses between the green arrow and the tank itself.

If you don't know what the flow rate is then you need all the details regarding the supply pressure, pipe length and diameters etc so that you can first calculate the flow rate. If you have all these details and you have worked out the flow rate then you could work from the left as described by bimr, or you could work from the right. Basically, you need to work from a point of known pressure and calculate all the losses from the known point to the green arrow.

Katmar Software - AioFlo Pipe Hydraulics

http://katmarsoftware.com

"An undefined problem has an infinite number of solutions"

 

[BigInch]

One thing you might be interested in is the maximum pressure at that point, which could reach around 10 bars, if a tank valve was closed.

Independent events are seldomly independent.

 

[LittleInch]

Katmar is completely correct. The thing missing from your sketch is the pressure in the air space above the liquid. If this is greater that atmospheric then you need to add this to the static head of 2m. If the total pressure at the pipe into the tank is more than the equivalent of 10m of your fluid (if it's water this is close to 1barg), then flow could be out of the tank not into it and therefore the pressure at your point will be the static head plus gas pressure minus friction losses from the tank to your point.

Note all these assume the pipe is fully liquid. If the pipe entered into the gas void at the top, then all bets are off unless the flow is such that the pipe remains fluid filled.

Confused you?

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[BigInch]

Thanks for catching my decimal point error little guy.

Independent events are seldomly independent.