Relationship between Reynolds number and plug flow
Relationship between Reynolds number and plug flow
(OP)
I have a situation where I have a 3" pipe and want to reach a certain residence time in the pipe. The fluid is nylon at approximately 300 poise. I've done an experiment and found that I get channeling. My pipe length is 36" and flow is about 16 lb/hr. I can get 40 minutes RT when filling an empty pipe, but doing a tracer study, I found that it is only 20 minutes, which suggests channeling. I am wondering if there is too small of a Reynolds number to achieve true plug flow. Is there some correlation there? What are the "rules of thumb" for PFR's?
The pipe is vertical and filling from the bottom. Should I try using a static mixer?
The pipe is vertical and filling from the bottom. Should I try using a static mixer?





RE: Relationship between Reynolds number and plug flow
Plug flow doesn't happen until you have not just turbulent flow, but fully developed turbulent flow (Re > 10,000). Doubtful that you're going to get Reynolds numbers that high with a viscosity of 30,000 cP at anything approximating a reasonable pressure drop.
You NEED static mixers, and even single tube static mixers may not be enough.
RE: Relationship between Reynolds number and plug flow
RE: Relationship between Reynolds number and plug flow
Thanks for the insight. I doubt I can realistically get the Reynold's number over 1 with nylon and my equipment.