Blood viscosity dependence of tube diameter and hematocrit

This is a brief quotation of results reported in the following valuable article:

A.R. Pries, D. Neuhaus and P. Gaehtgens: “Blood viscosity in tube flow: dependence on diameter and hematocrit” in American Journal of Physiology - Heart and Circulatory Physiology, Vol. 263, Issue 6, 1992, pp H1770-H1778.

The relative viscosity of blood (relative to water) at body temperature in dependence of the tube diameter D in μm is:

       η_{rel 0.45} = 220 e^–1.3D + 3.2 – 2.44 e^{–0.06D0.645}.

The dependence of the hematocrit is as follows:

in which for hollow fiber dimensions actual for the use in dialyzers C ≈ 0.8 and H_ctD is the overall hematocrit of the blood flowing through the dialyzer (not the specific hematocrit inside the hollow fiber).

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