Pressure waves in 32" Pipeline

[PipelineDeptTME]

Hello everybody,

I am doing dynamic stress analysis of 32" Diesel pipeline. Due to the closure of a ball valve, a fluid hammer travelling backwards is generated. The pipe has many vertical loops and horizontal direction changes. Now, my question is: what happen to the pressure wave when it hits such vertical and horizontal direction changes (imagine elbows)? I'm quite sure there will be a new wave travelling on the opposite direction, towards the ball valve. But what about the original one? Will continue its travel even going upwards or left or right? And if yes, will it be mitigated somehow?


Thank you

 

[LittleInch]

The pressure wave continues through bends and sections, gradually being attenuated by pipe friction and a small effect by the back wave coming from any valve, elbow or bend. I assume you're using a dynamic flow analysis programme to applause the pressure wave propagation. Translating rapid fluid pressure rise into mechanical force is not straightforward and it would be interesting to know how you're doing it.

My motto: Learn something new every day

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

 

[BigInch]

Significant reflections (NOT SMALL, unless you regard 50% as small), other than those caused by completely closed valves or dead ends, are generated by reductions in the cross-sectional area of flow, the reflected pressure, and pressure passing through being directly related to the change in cross-sectional area of flow. That applies to partially closed valves equally as it does to reducers, or "expanders". While there may be some, I don't believe that pressure transients caused by "non-reducing" bends will be significant.

Independent events are seldomly independent.

 

[LittleInch]

I meant an open reduceded bore valve - sorry for misunderstanding...

Just think of a wave going along an open square channel - it will continue round a smooth bend with a bit of back wash, but not much. Only when it hits a solid object or reduction in channel width will it refect a significant "wave" backwards.

My motto: Learn something new every day

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