Transitional region between viscous and molecular flow

9 Transitional region between viscous and molecular flow 

Integrating between r = 0 and r = R, as in the derivation of equation (1.2), and neglecting the term in X, gives the volume flowrate as  

Making the same substitutions used in deriving equation (1.10) gives  

Lea and Nurse [36] arrived at the same equation by assuming a slip velocity at the capillary walls. Carman [7] added an extra term to 

PolseuiUe s equation, which included a coefficient of external friction, to take account of slip to derive a similar expression. 

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