Corrections to Rotational Flow

As discussed in Section 7.4 and using the principle of superposition, the flow components were separated into rotational flow and pressure flows. The equation for the total flow and the components are as follows  

To obtain the correction factors, the rotational flow rate must be calculated using the generalized Newtonian method and the three-dimensional numerical method 

The rotational flow rates were calculated by setting the pressure gradient (dP/dz) to zero. The ratio of the rotational flow rate calculated using the numerical method to that of the generalized Newtonian method is defined as as follows  

Since the generalized Newtonian method was based on a constant viscosity for the entire channel, any factor that would cause the viscosity to vary in the channel may cause F to be different from 1. The factors known to cause the viscosity to 

correction factors as a function oiH/Wior single-flighted, square-pitched screw geometries are shown in Fig. 7.25. For these cases, only the channel depth was varied. 

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