Reynolds number is an important parameter for characterizing the flow characteristics of fluids in pipes.Based on the complex rheological model of Carreau-Extended(referred to as Carreau-E)non-Newtonian fluid containing yield stress,time constant and power law index and the force balance equation,the generalized Reynolds number expression of laminar flow in a fully developed Carreau-E fluid in a circular pipe was derived.It was further extended to Carreau,Herschel-Bulkley,Power-law and Bingham,four common non-Newtonian fluids and Newtonian fluids.Through a comparative study,it is found that the experi-mental values of Darcy friction factors for different types of fluids flowing through pipes are in good agreement with the predicted values,and the relative errors are basically within±10%.This study can provide a basis for determining the flow patterns of pipe flows for different non-Newtonian or Newtonian fluids.
维普
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