Determine shaft dia of vertical submersible pump

[sonu49]

Hi,
I need to determine shaft dia of a vertical submersible pump which is supported by two bearings.

I just wonder only torque consideration is enough to determine the shaft dia
or do i need to consider bending moment too? If yes what would be the BM equation. If so where will be the maximum bending.

Thanks in Advance..

 

[desertfox]

sonu49

I would base it on torque.
What would be causing a bending moment in a vertical pump that you have provided zero information on.

desertfox

 

[Artisi]

you also need to consider critical speed based on diameter and bearing spacing.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[sonu49]

Thanks desertfox and Artisi for reply...

desertfox,
the impeller radial thrust at the end of shaft may cause bending (if i am not wrong)

i was provided with axial and radial thrust at impeller for calculation. in such case how to proceed for shaft dia. some guidence on calculation is more helpful.

thanks in advance.

 

[bimr]

Why do you want to be able to calculate the shaft diameter? Pump manufacturers select their shaft diameters for practicality and cost if manufacturing. There are considerations such as: inventory of parts for multiple pump uses of the same pump part, pump wear, pump durability, cost of manufacturing part from different metals, capability of manufacturing facilities, etc.

The way an engineer does it is to look through various pump manufacturer's catalogs and observe what the manufacturer's have selected for shaft diameters.

 

[desertfox]

Hi sonu49

This link might help:-

http://www.mcnallyinstitute.com/01-html/1-06.html

In future when you have other information relating to your question please provide it in your initial post as this saves valueable time later, ie one post instead of several giving the information we might need to help you.

Regards

desertfox

 

[Artisi]

This is sounding very much like a homework question.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[BigInch]

For ... desertfox.

From "BigInch's Extremely simple theory of everything."

 

[1gibson]

Size shaft for torque and design the bearings to address other issues (critical speeds, radial support.)

Unless you are done with the bearing design, with an unknown shaft size...