Shear stress in plate heat exchanger 2

[NICKT16]

How to calculate shear stress in plate heat exchnager ? Any once can help me ?

Thanks


Nick

 

[metengr]

NICKT16;

Your question is vague. What exactly are you asking? Also, add more detail or background information to your question for better responses.

 

[NICKT16]

Sorry about that. Let me explain you.

We want to purchase plate and frame heat exchanger for our application. I understand that wall shear stress is important to keep the plate heat exchanger from plugging. We would like to specify the shear stress value in our specification.

Hope this information will help.

 

[jte]

I understand that wall shear stress is important to keep the plate heat exchanger from plugging.

Huh? Are you sure you aren't referring to shear in the fluid near the wall? Maybe I'm a bit slow (laminar thinking...), but I don't understand how the state of stress in the steel can have an impact on fluid flow behavior.

jt

 

[monaco8774]

If you are talking about shear rates to prevent formation of sludge/ wax or non newtonian behaviour at the wall try using

shear proportional to 8V/D

V = velocity
For D use equivalent diameter = 4 x surface area over wetted perimiter

Howvere your best off just communicating the fluid properties to the vendor and letting them deal with it.

 

[Latexman]

If you Google "shear stress" AND "parallel plates" you get over 42,000 hits.

What value of shear stress or shear rate keeps the plates clean?

If your fluid is fibrous, the number of points of contact between the two plates gets important too. They can cause the heat exchanger to act as a filter. This is NOT good!

Good luck,
Latexman