en>Tbhotch: Reverted edits by 69.146.143.26 (talk) to last revision by Dougher (HG)

2013-09-28T23:58:33Z

Reverted edits by 69.146.143.26 (talk) to last revision by Dougher (HG)

← Older revision		Revision as of 01:58, 29 September 2013
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	~~I am Humberto from Bretforton doing my final year engineering~~ in ~~Creative Writing~~. ~~I did my schooling~~, ~~secured 89%~~ and ~~hope~~ to ~~find someone~~ with ~~same interests~~ in ~~Lapidary~~.<br><br>~~Here~~ is ~~my site;~~ [http://www.~~wikipedia~~.~~org~~/ ~~cafe~~]		The '''Moody chart''' or '''Moody diagram''' is a graph in [[dimensionless numbers\|non-dimensional]] form that relates the [[Darcy-Weisbach friction factor]], [[Reynolds number]] and [[relative roughness]] for fully developed [[pipe flow\|flow]] in a circular pipe. It can be used for working out pressure drop or flow rate down such a pipe.

			==Description==
			This dimensionless chart is used to work out pressure drop, <math>\Delta P</math> (Pa) (or head loss, <math>h_{\mathrm{f}}</math> (m)) and flow rate through pipes. Head loss can be calculated using the [[Darcy–Weisbach equation]]:

			:<math>{h_{\mathrm{f}}=f\frac{l}{d}\frac{V^2}{2\,g}};</math>

			( not to be confused with the [[Fanning equation]] and the [[Fanning friction factor]]:

			:<math>{h_{\mathrm{f}}=4f\frac{l}{d}\frac{V^2}{2\,g}},</math>

			which uses a friction-factor equal to one fourth the Darcy-Weisbach friction factor).

			Pressure drop can then be evaluated as:

			:<math>\Delta P = \rho\,g\,h_{\mathrm{f}}</math> or directly from <math>\Delta P =f \frac{\rho V^2}{2}\frac{l}{d}, </math>

			where <math>\rho </math> is the density of the fluid, <math>V</math> is the average velocity in the pipe, <math>f</math> is the friction factor from the Moody chart, <math>l</math> is the length of the pipe and <math>d</math> is the pipe diameter.

			The basic chart plots Darcy–Weisbach [[friction factor]] against [[Reynolds number]] for a variety of relative roughnesses and flow regimes. The relative roughness being the ratio of the mean height of roughness of the pipe to the pipe diameter or <math>\epsilon \over d</math> .

			[[Image:Moody diagram.jpg\|thumbnail\|330px\|Moody diagram showing the Darcy-Weisbach friction factor plotted against Reynolds number for various roughnesses]]

			The Moody chart can be divided into two regimes of flow: [[laminar flow\|laminar]] and [[turbulent flow\|turbulent]]. For the laminar flow regime, the Darcy–Weisbach [[friction factor]] was determined analytically by [[Poiseuille]] and <math>\frac{64}{Re}</math> is used. In this regime roughness has no discernible effect. For the turbulent flow regime, the relationship between the friction factor and the Reynolds number is more complex and is governed by the [[Colebrook equation]] which is implicit in <math>f</math>:

			:<math>{1 \over \sqrt{\mathit{f}}}= -2.0 \log_{10} \left(\frac{\frac{\epsilon}{d}}{3.7} + {\frac{2.51}{Re \sqrt{\mathit{f} } } } \right) , \text{turbulent flow}.</math>

			In 1944, [[Lewis Ferry Moody]] plotted the Darcy–Weisbach friction factor into what is now known as the Moody chart.<ref>{{citation \| first=L. F. \| last=Moody \| title=Friction factors for pipe flow \| journal=Transactions of the ASME \| volume=66 \| issue=8 \| pages=671–684 \| year=1944 }} [http://www.chem.mtu.edu/~fmorriso/cm310/MoodyLFpaper1944.pdf paper on mtu.edu]</ref>

			The [[Fanning friction factor]] is 1/4 the Darcy–Weisbach one and the equation for pressure drop has a compensating factor of four.

			==References ==
			<references/>

			[[Category:Fluid dynamics]]
			[[Category:Hydraulics]]
			[[Category:Piping]]

en>AvicAWB: clean up, removed orphan tag using AWB

2011-09-08T05:26:50Z

clean up, removed orphan tag using AWB

New page

I am Humberto from Bretforton doing my final year engineering in Creative Writing. I did my schooling, secured 89% and hope to find someone with same interests in Lapidary.<br><br>Here is my site; [http://www.wikipedia.org/ cafe]

Absolute molar mass - Revision history

en>Tbhotch: Reverted edits by 69.146.143.26 (talk) to last revision by Dougher (HG)

en>AvicAWB: clean up, removed orphan tag using AWB