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Blood‐gas transfer in an axial flow annular exchanger
Author(s) -
Chang HsinKang,
Mockros Lyle F.
Publication year - 1971
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690170229
Subject(s) - laminar flow , chemistry , dimensionless quantity , mechanics , volumetric flow rate , radius , thermodynamics , materials science , physics , computer security , computer science
The rates of hemoglobin saturation and carbon dioxide reduction in blood flowing in an annular‐shaped membrane exchanger were studied theoretically by considering two limiting cases: the fluid‐limited case and the wall‐limited case. The blood is assumed to flow axially with a fully developed laminar profile. In the fluid‐limited analysis the membrane wall is assumed to be infinitely permeable, so the efficiency of the oxygenator depends solely on the rate of gas transport within the blood. In the wall‐limited case the blood is assumed to have infinite transport ability, thus the efficiency of the oxygenator is limited by the diffusion rate through the wall. For realistic radii ratio, the oxygenator is fluid limited, thus suggesting the need for enhanced blood mixing. In the fluid‐limited case the rate of gas transport depends on the radii ratio and a dimensionless length, which is independent of the cylinder sizes. If P O 2 = 715 mm. Hg and P CO 2 = 0 mm. Hg are maintained at both walls, oxygenation is the slower process. For the same flow rate the length required for complete hemoglobin saturation in the annulus with an inner to outer radius ratio of 0.95 is 1/65 of that required in a circular tube.