HI 9.6.6, E.2 Flow Straightening Devices

[hondashadow1100vt]

I am looking for any/all information and/or data on flow straightening devices for pump inlet piping flow conditioning.

HI 9.6.6, E.2 (informative, not part of the standard) indicates that in some instances where the required pump inlet straight length of piping cannot be achieved, flow straightening (e.g. vanes) devices may be a consideration with mutual consent of the pump supplier and installer, or with applicable and acceptable flow analysis tools.

Thank you for any input/feedback that you may be able to offer!

(Note: I originally posted this under the Pipelines, Piping and Fluid Mechanics engineering Forum however I now see that the pump forum seems more appropriate for this subject matter)

 

[LittleInch]

Try looking up ISO 5167 or google "ISO flow straightener" of flow conditioner


I've installed insert flanges like this on the pump inlet flange.

If it's good enepough for a metering system its good enough for pumps.

You also see sometime guided vane elbows.

https://empoweringpumps.com/metraflex-suction-diffuser-vanes-pump-applications/

Your post is rather vague. Can you elaborate on your issue or question?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[hondashadow1100vt]

LittleInch:

Thank you for the suggestions. Your suggestions have led to the following information/insights as this subject pertains to pump inlet conditions:

Non-uniform flow may exhibit:
- swirl
- assymmetry
- etc.

non-uniformity of the velocity exiting the elbow can cause local acceleration at the impeller vanes, resulting in low-pressure areas and cavitation.” Suction Diffuser Vanes for Pump Applications (August 29, 2017, Empowering Pumps & Equipment), (

https://empoweringpumps.com/metraflex-suction-diffuser-vanes-pump-applications/)

Poorly developed flow may result in:
- Cavitation
- excessive vibration
- poor pump performance
- bearing failure
- seal failure
- Impeller failure
- Impeller imbalance
- noise
- high maintenance costs
- high power consumption
- Increased head
- Decreased flow

Information from the flow metering industry:
- Recommended straight pipe diameters for flow measurement: 25 to 40 x D (upstream) (or as high as 95D); 4 to 5 x D (downstream) (or as high as 7D)
- Other piping standards are closer to 5xD upstream (or less)
- LxD may be shortened via use of flow conditioners
- often insufficient physical space to achieve recommended LxD

Types of flow conditioners:
- folded vane
- twisted vane (imparts rotation on flow)
- tube
- Zanker
- fin
- disturbance plate (Sprenkle)
- Vortab (swirl reduction via generation of small counter vortices)
- devices should only be installed in extreme cases after all options have been considered

One might consider quantifying the inferred effects of flow conditioners via before and after vibration monitoring.

 

[nondimensional]

Type of flow conditioning depends on the media you are pumping. What is your pump capacity, type and media?

I have seen & used baskets on clean media pumps, single vanes on large sewage pumps, and diffusers on small end suction units.

 

[hondashadow1100vt]

nondimensional:

The media is raw water. (also interested in wastewater).
Pump capacity is 4 MGD. (Also interested in other capacities, generally speaking)

Interesting point about the single vane for larger sewage pumps.

Thank you!