Erosion by what media?
Clean water? then it is zero until you get to sonic velocities.

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Plymouth Tube

Hi,

By D2O (heavy water). I want to calculate the erosion on a stainless steel nozzle after 35 years of operation. The velocity of the fluid is 10 m/s.

I need to know which formula or theory should apply for this kind of steel (AISI 304)

Can you help me?

Best regards!

an orifice or a smooth nozzle? If it is an orifice you will probably have some cavitation damage. If it is a nozzle then these are fairly low flow velocities and I don't see why there would be any erosion.
Talk with your flow nozzle supplier. I have heard them say that they have tested many old nozzles and find them to still be in specification.

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Plymouth Tube

Hi,

Yes, it is a Nozzle (not an orifice) attached to a pipeline. The client requested to us to consider the posibility of erosion. I´m quite sure that no erosion could happen there. However, I have to present something (docs, calcs, code, etc) to support my theory of no erosion.

I´m thinking that If I can calculate the erosion velocity rate for AISI 304 will be good enough.

I have the expresion to calculate the erosion rate according Bitter. But the unit of it is mg/g and in not time dependence.

Any idea?

API RP 14E, Equation 2.14 might help you out as a starting point.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.

In clean services free of solids, very high velocities do not result in erosion even over comparatively long design service lifetimes. Take for instance the plugs and seats of control valves. Velocities in these can be 10x the velocity in piping constantly, i.e. on the order of 100 ft/s, and significant erosion in clean services is not observed.

If there is particulate matter present, that makes all the difference. Erosion-corrosion, i.e. erosion of the passive film leading to corrosive attack, is another matter entirely.

I believe that there was a paper at this years EPRI Heat Rate conf where a nozzle producer talked about testing flow nozzles that were decades old and they still met original calibrations.
I'll look for it.

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Plymouth Tube

EdStainless, thanks a lot!

Hi EdStainless,

Could you find the paper ?

Best regards!

regrettably those comments are not in the printed paper.
Sorry

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Plymouth Tube

If the nozzle is a solid piece. Like a Venturi meter then you can do ultrasonic testing to see the thinning, if there is any.
You might be able to x-ray the nozzle to confirm you don't have problems either.
Just a thought.

Regards

StoneCold