Reynolds Number (Turbulent Flow)
Reynolds Number (Turbulent Flow)
(OP)
Hi,
I am working out Reynolds number to get a turbulent flow for flushing out our system.
I have found various website’s which state different answers when turbulence is achieve turbulent flow (Re> 4000, 3000 and 2320).
Just wondering which is correct? I initially thought it was more than 4000.
Many Thanks,
D.
I am working out Reynolds number to get a turbulent flow for flushing out our system.
I have found various website’s which state different answers when turbulence is achieve turbulent flow (Re> 4000, 3000 and 2320).
Just wondering which is correct? I initially thought it was more than 4000.
Many Thanks,
D.





RE: Reynolds Number (Turbulent Flow)
Good luck,
Latexman
RE: Reynolds Number (Turbulent Flow)
Good luck,
Latexman
RE: Reynolds Number (Turbulent Flow)
RE: Reynolds Number (Turbulent Flow)
David Simpson, PE
MuleShoe Engineering
"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
RE: Reynolds Number (Turbulent Flow)
Said what above I’m with both Latexman and zdas04 in considering Re = 10,000 as a valid threshold for turbulence.
RE: Reynolds Number (Turbulent Flow)
If there are flat plates involved, turbulent Rn can be over a million.
"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek
RE: Reynolds Number (Turbulent Flow)
RE: Reynolds Number (Turbulent Flow)
David Simpson, PE
MuleShoe Engineering
"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
RE: Reynolds Number (Turbulent Flow)
Solve(64/Re=Solve(1/(f^0.5)=-2/ln(10)*ln(k/(3.7*d)+2.51/(Re*f^0.5)),f),Re)
RE: Reynolds Number (Turbulent Flow)
At some point, the friction factors computed one way versus the other will diverge, with Re on the abscissa, presumably somewhere to the right of where they are closely equal.
RE: Reynolds Number (Turbulent Flow)
For instrument tubing you need to go to the equations for capillary flow and they are pretty messy. I did some work a few years ago (1998 actually) to try to determine how much gas was vented to atmosphere with pneumatic valves operated on natural gas. Part of that work was to try to asses flow rates in small tubing. I evaluated this by timing the shut time on fail-closed pneumatic devices. With no exhaust tubing I was able to calculate close time to within miliseconds. When we added 3 ft of exhaust tubing I was able to develop an empirical relationship that matched closing time pretty well--it was nowhere close at 3.5 ft of tubing or 2.5 ft of tubing. I finally gave up and wrote my paper assuming local exhaust, a little bit sleazy but the paper was accepted by SPE and no one ever asked "what happens to these numbers if there is exhaust tubing" so I never had to admit I didn't have a clue.
David Simpson, PE
MuleShoe Engineering
"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.