Disjunctive sequence: Difference between revisions
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'''Atkinson friction factor''' is a measure of the resistance to airflow of a duct. It is widely used in the [[Underground mine ventilation|mine ventilation]] industry but is rarely referred to outside of it. | |||
Atkinson friction factor is represented by the symbol <math>k</math> and has the same units as air density (kilograms per cubic metre in [[SI|SI units]], pounds per cubic foot in [[Imperial unit]]s). It is related to the more widespread [[Fanning friction factor]] by | |||
<math> | |||
k = \frac{1}{2}\rho f, | |||
</math> | |||
in which <math>\rho</math> is the density of air in the shaft or roadway under consideration and <math>f</math> is Fanning friction factor (dimensionless). It is related to the [[Darcy friction factor]] by | |||
<math> | |||
k = \frac{1}{2}\rho \frac{\lambda}{4}, | |||
</math> | |||
in which <math>\lambda</math> is the Darcy friction factor (dimensionless). | |||
It was introduced by John J Atkinson in an early mathematical treatment of mine ventilation (1862) and has been known under his name ever since. | |||
==See also== | |||
* [[Atkinson resistance]] | |||
==References== | |||
* NCB Mining Dept., ''Ventilation in coal mines: a handbook for colliery ventilation officers,'' National Coal Board 1979. | |||
==Further reading== | |||
* [http://www.mvsengineering.com/admin/images/pdfs/Practical_Values_of_Friction_Factors.pdf 1999 paper giving the derivation of <math>k</math>] | |||
* Atkinson, J J, ''Gases met with in Coal Mines, and the general principles of Ventilation'' Transactions of the Manchester Geological Society, Vol. III, p.218, 1862 | |||
[[Category:Fluid dynamics]] | |||
[[Category:Mine ventilation]] | |||
Revision as of 18:31, 10 December 2013
Atkinson friction factor is a measure of the resistance to airflow of a duct. It is widely used in the mine ventilation industry but is rarely referred to outside of it.
Atkinson friction factor is represented by the symbol and has the same units as air density (kilograms per cubic metre in SI units, pounds per cubic foot in Imperial units). It is related to the more widespread Fanning friction factor by
in which is the density of air in the shaft or roadway under consideration and is Fanning friction factor (dimensionless). It is related to the Darcy friction factor by
in which is the Darcy friction factor (dimensionless).
It was introduced by John J Atkinson in an early mathematical treatment of mine ventilation (1862) and has been known under his name ever since.
See also
References
- NCB Mining Dept., Ventilation in coal mines: a handbook for colliery ventilation officers, National Coal Board 1979.
Further reading
- 1999 paper giving the derivation of
- Atkinson, J J, Gases met with in Coal Mines, and the general principles of Ventilation Transactions of the Manchester Geological Society, Vol. III, p.218, 1862