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ASAIO CARDIAC ABSTRACT

THREE DIMENSIONAL (3D) OXYGEN (O2) TRANSFER MODELLING OF AN INTRAVENOUS HOLLOW FIBER GAS TRANSFER DEVICE (IH-FGTD) USING COMPUTATIONAL FLUID DYNAMICS (CFD)

Mallabiabarrena, I; Taub, S; Jegger, D; von Segesser, L K

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In this work we report on recent efforts in our laboratory to couple experimental and computational approaches to analyze the gas transfer performance of an IHFGTD. We describe a 3D computational approach to characterize blood motion and O25 transfer in a simplified IHFCTD. Modelling each hollow fiber (HF) of the device by a 3D numerical model is an enormous task. We propose a simplified computational model to analyze blood flow and O2 transfer between HF and blood. This is based on a reduced number of crimped HF (N = 20) regularly distributed. Experimental approach using a saline solution is also carried out to calculate gas transfer performance (VO,) of our prototypes for several inlet conditions. Then, we compute the mass transfer coefficient (VO2) with blood taking the equation K1=αReβSc1/3 and using the procedure proposed by Mockros. These results are derived using 3 IHFCTD protatypes placed in an in-vitro set up. Their gas exchange area is 0.5 m2. Navier-Stokes equations for blood flow and advection-diffusion for O2 transfer are solved using a CFD code (Fluent, Lebanon, NH). Appropriate boundary conditions (BC) are set for blood motion and O2 transfer in blood. The fluid is set as steady, laminar, incompressible and it is assumed to be Newtonian. Inlet condition is set for different blood flow rates (1 ≥Qb≥3 1/min). Robin BC for O2 transfer is set using experimentally deduced mass transfer coefficients (3.1≥K1≥6.8*10−5 m/s). CFD techniques offers a detailed understanding of blood mechanics and O2 transfer for medical devices.

Copyright © 2004 by the American Society for Artificial Internal Organs