Dear all
How to calculate the preset gas pressure in hydropneumatic tank in case I use with bladder instead of using without bladder for the following data
Pressure head from initial condition = 42.87 m
Initial volume of gas = 2.5 m3
Total volume of tank = 7 m3
Gas law exponent = 1.4.
Regards.
Sayed Elhagar
Hello Sayed,
The gas preset pressure is a user-defined value which is typically some percentage of the pipeline pressure. If you do not know the value you need to use (either from regulations, tank manufacturer data, or engineering judgment), you can calculate this based on an assumed initial bladder size (gas volume).
The following link has the steps that you can take to calculate this: Entering Hydropneumatic tank gas preset pressure based on assumed initial bladder volume.
Regards,Scott
Hi Scott,
Thanks for the information you provided, but the calculations is based on gas law exponent =1.0
How this calculation will be different when I use gas law exponent =1.4 as I mentioned in my question
Regards
For this particular calculation, you would use 1.0 for the gas law exponent, because HAMMER uses the isothemal gas law for this calculation. An exponent of 1.4 will apply during the transient simulation, which is assumed to be adiabatic. See the following article for an explanation:
Use of the Gas Law Exponent During Initial Conditions vs. Transient simulation
K = PVK = (42.86+10.33)*(2.5)K = 132.975
P = K/VP = (132.975 / 7)-10.33P = 8.67 m
Regards,
Jesse DringoliTechnical Support Manager, OpenFlowsBentley Communities Site AdministratorBentley Systems, Inc.