NPSH calculation program who can share? 5

[TPP393]

Dear all experts,

I need a simple calculation software for double check the NPSH when sizing punp, please share this if someone has this.

Thank you.

TPP393

 

[Homayun]

you don't need a special software for that! All you need to know is:
A: Drum pressure
B: Vapor pressure (usually the same as the drum pressure if at equilibrium)
C: friction losses in suciton line
: static height between your drum bottom tangent line and pump datum.

That's it..

 

[Artisi]

NPSH for suction lift

NPSH = Ha -Hvpa - Hst - Hfs

NPSH for flooded suction

NPSH = Ha -Hvpa +Hst -Hfs

NPSHr comes from the pump data

 

[nickelkid]

http://www.pumpcalcs.com/calculators/view/66/

 

[formz]

TPP93,

When you talk in NPSH you have always to talk about NPSH required and NPSH available.

- The NPSH required is given by the pump manufacturers and is determined by lowering the NPSH available to a certain pump until the pump head decreases 3%;
- The NPSH available is easily calculated as our colleagues explained above.

For avoiding cavitation and for having a long life in your pump, always keep NPSHa>NPSHr.

Regards,
formz

 

[rmw]

I concur with Formz, but I would like to change the ">" in his last statement and insert the words "well above".

rmw

 

[rmw]

And, I gave a start to RCHandy for the link; I have already used it.

rmw

 

[athomas236]

See ANSI/HI 9.6.1, good advice even though withdrawn.

athomas236

 

[roadwhore75]

Here's a program I wrote almost 10 years ago to help project engineers size pumps. I've used this successfully to size about 50 pumps.

I suggest you make an extra copy in case you scramble something.

The instructions are simple. The yellow cells are entries. There are sheets attached for physical properties and calculating K for the fittings. The program estimates motor efficiencies using information I collected from Pacific Gas and Electric. Hydraulic efficiency is either an entry or can be estimated using equations from Chemical Engineering Progess (CEP) and the Hydraulic Institute. You will see that it presents the information in a single cut sheet. Sheets are available for the two types of pumping configurations: suction lift and suction head. For the later, there is a static head to compensate for the losses to the pump eye. Choose the sheet based on configuration.

This program will work for slurries, laminar flow, etc., assuming the fluid will flow.

There are a few assumptions about the Ks for various fittings but these are unavoidable.


Use at your own risk.

Dirk Willard

 

[Artisi]

Dirk

Looks to be a very comprehensive and useful programme, however, I feel you should clarify / expand re slurry pumping - it is possibly ok for chemical slurries but don't see it working for mineral slurries which can become very complex as far as friction losses and pump de-rating requirements.