high viscosity flow with low Reynolds' number
high viscosity flow with low Reynolds' number
(OP)
How can I adequately calculate pressure drop in a line if viscosity is ~3000cP and Reynolds' number is under 10? When I look at a Moody plot, it doesn't seem to be anywhere near the plotted curves?
Using the common relation of 64/Re=f doesn't seem to be giving reasonable results either.
Based on previous jobs, this should not result in very high pressures, or much pumping power.
I don't expect that pressure drop on the discharge side of my metering pumps will be a problem, but the NPSHa could be.
Using the common relation of 64/Re=f doesn't seem to be giving reasonable results either.
Based on previous jobs, this should not result in very high pressures, or much pumping power.
I don't expect that pressure drop on the discharge side of my metering pumps will be a problem, but the NPSHa could be.





RE: high viscosity flow with low Reynolds' number
Good luck,
Latexman
RE: high viscosity flow with low Reynolds' number
If you combine this with the Darcy-Weisbach equation you in fact get Poiseuille's Law.
Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com
RE: high viscosity flow with low Reynolds' number
"If everything seems under control, you're just not moving fast enough."
- Mario Andretti- When asked about transient hydraulics
http://virtualpipeline.spaces.msn.com
RE: high viscosity flow with low Reynolds' number
Thanks for the suggestions. I'll have to re-check my numbers, again.
RE: high viscosity flow with low Reynolds' number
RE: high viscosity flow with low Reynolds' number
RE: high viscosity flow with low Reynolds' number
When I asked if they have any quantitative characterization for that behavior; they said it's not typically necessary in normal use.
Unless I find some good and easy to use info quickly, I'm going to have to guess on pipe & valve sizing based on past projects. I don't think my boss is going to pay, or wait, for lab testing and another round of calcs.
Thank you all for your help.
RE: high viscosity flow with low Reynolds' number
"If everything seems under control, you're just not moving fast enough."
- Mario Andretti- When asked about transient hydraulics
http://virtualpipeline.spaces.msn.com
RE: high viscosity flow with low Reynolds' number
Conversely, if the pipes i not heated and poorly insulated then the effective pipe diameter can become very much smaller than you think. Chocolate lines are a classic example, the chocolate cools at the pipe wall, its viscosity increases, it slows down and it cools some more. Most of the lfow takes place in the very centre of the pipe line at far higher flow velocities than you'd expect based on pipe size.
JMW
www.ViscoAnalyser.com