Calculating the full volume of oil that enters an accumulator

[Claus.A]

Hi

I have been searching the literature for a formula, that gives me the full volume that enters an accumulator from standstill..
All the literature I have found, is the good old ΔV (working volume) based off accumulator size, P0, P1, P2 and an exponent.

This gives me the working volume between P1 and P2, but I also need to know how much oil enters between P0 and P1

Is there something painfully obvious that I am overlooking and can I get some help with this ?

Thank you in advance.

 

[hydtools]

Calculate the delta volume necessary to compress the accumulator gas from its precharge pressure to PO.

Ted

 

[Claus.A]

You mean to P1?

 

[hydtools]

Yes, P1. Assuming the empty precharge pressure is P0. Should have asked for OP definitions of P0, P1, and P2. In any case the change in volume from accumulator pressure P0 to P1 would be the volume of oil entering the accumulator from P0 to P1.
Fast or slow, adiabatic or isothermal, respectively.
Ted

 

[PNachtwey]

I have written articles about this for Hydraulics and Pneumatics.
Wow! a lot of people have copied. It was so long ago.
Accumulators: The unsung heroes of hydraulic motion control

https://www.hydraulicspneumatics.co...ors/Article/False/43954/TechZone-Accumulators

Peter Nachtwey
Delta Computer Systems

http://www.deltamotion.com

http://forum.deltamotion.com/

 

[Claus.A]

sooo


V*(1-(P2/P0)) wouldn't be unreasonable if the conditions are isotherm? (V being the accumulator volume)

and V*(1-(P2/P0)^(1/k)) for adiabatic conditions (k being the exponent, which I forget the English word for)?

PNachtwey: I do remember seeing the article years back.

Thanks for the replies so far!

 

[PNachtwey]

I use isothermal for operational conditions because there is little time for heat to be exchanged.
However, when charging I use adiabatic calculations because the accumulator is usually charge at ambient temperature then heated up to about 110-130 degrees F when running.


Peter Nachtwey
Delta Computer Systems

http://www.deltamotion.com

http://forum.deltamotion.com/

 

[hydtools]

Peter, that seems backwards. Use adiabatic when little or no heat is transferred, gas temperature varies during compression and expansion cycling.

Ted