Blake Number

Written by Jerry Ratzlaff on . Posted in Dimensionless Numbers

Blake number, abbreviated as Bl, a dimensionless number, is proportional to inertial force and viscous force and is used in momentum transfer and flow through beds of solids.


Blake Number formula

\(\large{ B =  \frac{ v \; \rho \; d_h }{ \mu \; \left( 1\;-\; \epsilon \right) }  }\)
Symbol English Metric
\(\large{ Bl }\) = Blake number \(\large{dimensionless}\)
\(\large{ \rho }\)   (Greek symbol rho) = density of fluid \(\large{\frac{lbm}{ft^3}}\) \(\large{\frac{kg}{m^3}}\)
\(\large{ \mu }\)  (Greek symbol mu) = dynamic viscosity of fluid \(\large{\frac{lbf-sec}{ft^2}}\) \(\large{ Pa-s }\)
\(\large{ d_h }\) = hydraulic diameter \(\large{ ft }\) \(\large{ m }\)
\(\large{ v }\) = velocity of fluid \(\large{\frac{ft}{sec}}\) \(\large{\frac{m}{s}}\)
\(\large{ \epsilon }\)   (Greek symbol epsilon) = void fraction \(\large{dimensionless}\)


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Tags: Force Equations