Estimation of momentum flow

The viscosity of a pure monatomic gas of molecular weight M may be expressed in terms of the Lennard-Jones parameters by 

The following semiempirical relation also predicts the viscosity of a gas mixture within an average deviation of —2%  

Here n is the number of chemical species in a mixture, the mole fraction of species i, p., the viscosity of species i at the system temperature and pressure, and A /, the molecular weight of species i. Mainly, the dependence of viscosities on composition is nonlinear for mixtures of gases. Many additional empirical equations are available for estimating viscosities of gases and gas mixtures at low and high densities (Reid et al., 1987) as well as for liquids, suspensions, and emulsions (Bird et al., 2002). 

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Example 2.1 Estimation of momentum flow Estimate the steady-state momentum flow, ryx, inlbf/ft2 when the lower plate velocity in Figure 2.3 is 0.5 ft/s in the positive x-direction. The plate separation is y = 0.001 ft, and the fluid viscosity is 1.46 X 10-5 lbf s/ft2. 

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