Non-Newtonian Capillary Flow

The non-Newtonian flow of liquids is too complex to be treated here at length, and we shall restrict ourselves to consideration of some cases specifically significant for lubrication science and technology. Curves such as B and C in Fig. 4-2 can be fitted to the de Waele-Ostwald power law 

When n = 1, Eqn 4-14 reduces to the Hagen-Poiseuille equation with c. 

Velocity distributions within a capillary column of liquid as computed by Metzner [5] for various values of n are shown in Fig. 4-5a. For 

A technique for the use of the power law model starts by putting Eqn 4-14 into logarithmic form  

If the plot of log Q, against log (tiP/2l) is a straight line, its slope is n. It then is possible to compute the value of c from either Eqn 4-15 or Eqn 4-14. 

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