Hi all,

We know that the hydraulic transient in a piping system causes an unbalanced peer pressure curves which generates the reaction force.

My question is whether this force caused by unbalanced pressure also acts on tees, reducers and blind flanges?

Thanks in advance.

Hi all,

Could anyone help me?

If you can get tee intersection point and another elbow pressure vs time data from SPS or Impulse hydraulic transient software pakage, you can calculation unbalance in tee intersection with other elbow.

but reducer and blind flanges normally not consider pressure unbalance force, the pressure thrust force had been taken by Bondorn effect in CII.

Limin

Limin, thanks for the answer.

The suction passage pump operates a hydraulic transient 7kgf / cm2.

I wonder if the transient thrust force acts on the tee due to change of direction as shown in the attached figure.

This force impacts the design of the anchor block? or it can be neglected?

Thanks in advance.

What is Bondorn effect ?

Pressure thrust is nothing to do with 'bourdon effect'.

I think the reason your not getting any responses is that we don't understand what you're asking.

You state that the suction side is operating at 7 kg//cm2 but then talk about unbalanced pressure thrust? Are you taking about the difference between the inlet/outlet pressures on your pump? If so, there is no unbalanced pressure thrust. The pump will resolve the pressures internally so that each side is balanced.

In the picture you show above, you have an anchor directly inline with the pump. Assuming that your pump is anchored and that you have temperature on the pipe, you will get extremely high loads due to restrained thermal growth.

Hi Hag,
Hydraulic transient must be caused by someting that disturb fluid steady state, such as, pump trip, valve closing,...
your are taking 7kg/cm2, is it a steady pressure? if it is transient surge pressure, it must be a time history file that is pressure vs time at a specified location, and you have to have points at each end of header, and tee, and 45degree elbow, those number normally calculated from hydraulic transient software such as, SPS, Impulse, ...

and then you can calculated unbalance force,
otherwise, how is your 7kg/cm2?
as Dan descripted your anchor,
and You also did not consider your pump thermal grow between your suction and discharge also pump elevation.

Regards,
Limin

Hi all,

The value (7KGF/CM2) was calculated by the software impulse being caused by the pump shutdown.
For the steady state the anchor block is fairly small with axial load of approximately 7ton.
For transient event condition the thrust force generated by the dP is 7kgf/cm2 in bends and tee, generates higher loads in anchor block, about 50ton. The piping have 30in of diameter.
This reasoning is correct?
There is a factor to be applied in 45 grados elbows for calculed unbalanced thrust force?