ON IDENTIFICATION OF FLOW REGIMES IN A POLYSPHERICAL MEDIUM WITH THE USE OF VELOCITY DEPENDENCES FOR THE LOSSES OF HEAD

It is shown that the ″universal″ expressions usually obtainable for the coeffi cient of hydraulic resistance Δp of a bed of granulated (granular) medium and for the magnitude of this resistance in a wide range of Reynolds numbers do not allow one to identify fl ow regimes and critical (transitional) values of Re = [Re] of the changes of regimes. With the use of substantiated approaches to the generalization of data on Δp in a bed of spheres, ″piecewise-linear″ (in logarithmic coordinates) dependences of Δp on Re and the values of [Re] = 60–80 have been obtained. Expressions
are given for Δp that are valid for laminar (Δp ~ Re) and postlaminar (Δp ~ Re1.75) regimes of fl ow. The question as to the role of porosity of the medium in the form of an alternatively considered strong power function (Δp ~ 1/ω4.2) is discussed as the one deserving attention
It is shown that the ″universal″ expressions usually obtainable for the coeffi cient of hydraulic resistance Δp of a bed of granulated (granular) medium and for the magnitude of this resistance in a wide range of Reynolds numbers do not allow one to identify fl ow regimes and critical (transitional) values of Re = [Re] of the changes of regimes. With the use of substantiated approaches to the generalization of data on Δp in a bed of spheres, ″piecewise-linear″ (in logarithmic coordinates) dependences of Δp on Re and the values of [Re] = 60–80 have been obtained. Expressions
are given for Δp that are valid for laminar (Δp ~ Re) and postlaminar (Δp ~ Re1.75) regimes of fl ow. The question as to the role of porosity of the medium in the form of an alternatively considered strong power function (Δp ~ 1/ω4.2) is discussed as the one deserving attention
Author:  D. A. Sandulyak, A. A. Sandulyak, V. A. Ershova, UDC 532.546; 532.685 A. V. Sandulyak, M. A. Kononov, and M. N. Polismakova
Keywords:  polyspherical medium (fi lling), porosity, speed of fi ltration, diameter of spheres, pressure drop, Reynolds number
Page:  181