Basis of the design model

Because the non-Newtonian behaviour is being taken into account, the equations for momentum continuity and energy respectively, take the form  

It is important to note that the temperature dependency of the viscosity has a strong influence on the computational strategy and this has an important effect on how the equations should be solved [9]. 

The system is clearly highly non-linear and, in order to obtain a converged solution, it is necessary to solve the problem initially without considering the buoyancy effect, i.e. the term (PoOi T—Tq)) of equation (6.1) is neglected. This 

Power (n) Model Maximum temperature rc) Average temperature ( C) Maximum shear stress (m/s ) 

The temperature distribution is also affected by the height of the impeller above the base and results of this study suggest that it should be at the mid-height position and not the commonly used value of one third the height. 

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