transients pressures with compressible gases

[CRG]

What is the best source (books, papers, etc.) for information on transient pressures for compressible single phase fluids in pipelines? I have worked with transients in pipelines with non-compressible fluids and I am trying to get a handle on the pressure gradients that would be generated with sudden valve closures (instantaneous to 8 seconds) for gas transmission piping. No specific project at this time; however, I need to increase my understanding for future natural gas & steam piping projects. I need some good night time reading???

Thanks for any information you might be able to provide.

 

[davefitz]

this is a "waterhammer" question. It relates to the pressure surge caused by the change in momentum of a leg of fluid decelerated due to a sudden closure of a valve, usually a check valve. I think the pressure is proportional to the mass of fluid in the fluid leg times the rate of cahnge of velocity per unit time. It can be dampened by the use of compressible bladders or slowing the speed of closure of the actuator.

try a google search on waterhammer.

 

[CRG]

Let me define my question further. When I said incompressible I was referring to liquids such as jet fuel, water, etc. The bulk modulus for these varies with temperature; however, when calculating transients for these fluids, it is assumed the there is an insignificant temperature change as the pressure wave travels through the fluid. With compressible fluids (gases) I am not sure how to get a handle on the bulk modulus. The gas will heat as it is compressed by the wave propagation. Perhaps, I need to go back to the fundamentals of thermodynamics to understand how to model this. Or, if there is a good reference for transients in gas pipelines, I could study that. As such, I am still looking for advice.

Thanks

 

[dbevil]

I researched this at length many years ago and the conclusion then was that the increase in pressure due to a sudden stoppage of gas was so small that it was not really within the accuracy of the hydraulic gradient calculation to begin with. At extremely high pressures and low temperatures, it may be more significant but the delta-p would still be small compared to the pressure.