The wall effect in capillary instruments: an improved analysis suitable for application to blood and other particulate suspensions

Article type: Research Article

Authors: Thomas, H.W.^{; *}

Affiliations: Physics Department, St. Mary’s Hospital Medical School, London, W.2, England

Note: [*] Present address: Physics Department, National Institute for Research in Dairying, Shinfield, Reading, Berks.

Abstract: The case of the flow of a particulate suspension through a capillary tube is considered, and an improved analysis in terms of a simple model, consisting of a clear annulus of the suspending phase surrounding a core of the suspension, is presented. The approximations of previous authors have been avoided. The thickness of the “effective” annulus is demonstrated, under readily realizable experimental conditions, to be the same irrespective of whether calculations are based on measurements of flow or of changes in the mean concentration within the tube. The method of analysis has been applied to the published results of previous authors, and the essential features of the wall effect have been deduced in the case of suspensions of mammalian red cells, and of rigid spheres. The need for further experimental data is indicated.

DOI: 10.3233/BIR-1962-1106

Journal: Biorheology, vol. 1, no. 1, pp. 41-56, 1962