0
TECHNICAL PAPERS: Fluids/Heat/Transport

Flow Mixing Enhancement from Balloon Pulsations in an Intravenous Oxygenator

[+] Author and Article Information
Amador M. Guzmán

 Departamento de Ingeniería MecánicaUniversidad de Santiago de ChileAlameda 3363, Estación Central Santiago, Chileag3w@andrew.cmu.edu

Rodrigo A. Escobar, Cristina H. Amon

Institute for Complex Engineered Systems, Departments of Mechanical Engineering and Biomedical Engineering, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, PA 15213

J Biomech Eng 127(3), 400-415 (Mar 02, 2004) (16 pages) doi:10.1115/1.1894260 History: Received July 15, 2002; Revised March 02, 2004

Computational investigations of flow mixing and oxygen transfer characteristics in an intravenous membrane oxygenator (IMO) are performed by direct numerical simulations of the conservation of mass, momentum, and species equations. Three-dimensional computational models are developed to investigate flow-mixing and oxygen-transfer characteristics for stationary and pulsating balloons, using the spectral element method. For a stationary balloon, the effect of the fiber placement within the fiber bundle and the number of fiber rings is investigated. In a pulsating balloon, the flow mixing characteristics are determined and the oxygen transfer rate is evaluated. For a stationary balloon, numerical simulations show two well-defined flow patterns that depend on the region of the IMO device. Successive increases of the Reynolds number raise the longitudinal velocity without creating secondary flow. This characteristic is not affected by staggered or non-staggered fiber placement within the fiber bundle. For a pulsating balloon, the flow mixing is enhanced by generating a three-dimensional time-dependent flow characterized by oscillatory radial, pulsatile longitudinal, and both oscillatory and random tangential velocities. This three-dimensional flow increases the flow mixing due to an active time-dependent secondary flow, particularly around the fibers. Analytical models show the fiber bundle placement effect on the pressure gradient and flow pattern. The oxygen transport from the fiber surface to the mean flow is due to a dominant radial diffusion mechanism, for the stationary balloon. The oxygen transfer rate reaches an asymptotic behavior at relatively low Reynolds numbers. For a pulsating balloon, the time-dependent oxygen-concentration field resembles the oscillatory and wavy nature of the time-dependent flow. Sherwood number evaluations demonstrate that balloon pulsations enhance the oxygen transfer rate, even for smaller flow rates.

Copyright © 2005 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Intravenous membrane oxygenator (IMO) and its main components within the vena cava

Grahic Jump Location
Figure 2

Schematic of the physical IMO device and close up of the IMO device midsection

Grahic Jump Location
Figure 3

First computational model: (a) schematic of the physical domain; and (b) computational domains with one, two and three fibers

Grahic Jump Location
Figure 4

Second computational model: (a) schematic of the physical domain; and (b) computational domain

Grahic Jump Location
Figure 5

Schematic representation of the computational domain of the first model with representations of type of boundary, cross sections, and typical points

Grahic Jump Location
Figure 6

Three-dimensional spectral element discretization and computational mesh: (a) first model with one fiber; and (b) second model with three fibers

Grahic Jump Location
Figure 7

Schematic representation of the computational domain of the first model with two different fiber configurations: (a) non-staggered; and (b) staggered

Grahic Jump Location
Figure 8

Numerical pressure gradient for a stationary balloon: (a) pressure gradient with the first model with one, two, and three fibers for non-staggered and staggered configurations; (b) pressure gradient with the first model as a function of the number of fibers; and (c) pressure gradient for the second model with three fibers

Grahic Jump Location
Figure 9

Pressure gradients with first model with one fiber for stationary and pulsating balloons

Grahic Jump Location
Figure 10

Schematic representation of the analytical model for pressure gradients for a stationary balloon: (a) concentric cylinders; (b) de-phased cylinders; and (c) “resting”

Grahic Jump Location
Figure 11

Analytical pressure gradients versus volumetric flow rate for a stationary balloon

Grahic Jump Location
Figure 12

Flow characteristics for first model with one fiber for a stationary balloon: (a) temporal evolution of the longitudinal velocity; (b) streamlines for a laminar Reynolds number of Re=455; (c) velocity vector representations for three planes perpendicular to the longitudinal direction; and (d) longitudinal velocity profiles at the tangential planes of Fig. 5

Grahic Jump Location
Figure 13

Velocity vectors for a stationary balloon for the first model with one, two, and three fibers, for non-staggered and staggered fibers placement

Grahic Jump Location
Figure 14

Longitudinal velocity profiles for the first model with two and three fibers for a stationary balloon in non-staggered and staggered configurations

Grahic Jump Location
Figure 15

Flow characteristics for a pulsating balloon with the first model 1 with one fiber: (a) temporal evolution of the three velocity components in a characteristics point of Fig. 5; (b) four instantaneous representations of the velocity field in one time period of balloon pulsations; and (c) pulsatile longitudinal velocity profiles for one time period

Grahic Jump Location
Figure 16

Flow characteristics for a stationary balloon with the second model with three fibers

Grahic Jump Location
Figure 17

Oxygen concentration field with the first model with one fiber for a stationary balloon: (a) iso-oxygen concentration curves; and (b) oxygen concentration profile at the A-A section of Fig. 5

Grahic Jump Location
Figure 18

Oxygen concentration field with model 1 with one fiber with balloon pulsations: (a) instantaneous three-dimensional representation and a close up of the side view of the oxygen concentration field in a smaller section of the computational domain; and (b) sequence of eight instantaneous representations of the oxygen concentration field of a cross section perpendicular to the longitudinal direction in one time period

Grahic Jump Location
Figure 19

Time average and space-averaged Sherwood number as a function of Reynolds number for a stationary and pulsating balloons with the first model with one fiber

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In