title: Experimental Approach to Visualize Flow in a Stacked Hollow Fiber Bundle of an Artificial Lung With Particle Image Velocimetry.
abstract: Flow distribution is key in artificial lungs, as it directly influences gas exchange performance as well as clot forming and blood damaging potential. The current state of computational fluid dynamics (CFD) in artificial lungs can only give insight on a macroscopic level due to model simplification applied to the fiber bundle. Based on our recent work on wound fiber bundles, we applied particle image velocimetry (PIV) to the model of an artificial lung prototype intended for neonatal use to visualize flow distribution in a stacked fiber bundle configuration to (i) evaluate the feasibility of PIV for artificial lungs, (ii) validate CFD in the fiber bundle of artificial lungs, and (iii) give a suggestion how to incorporate microscopic aspects into mainly macroscopic CFD studies. To this end, we built a fully transparent model of an artificial lung prototype. To increase spatial resolution, we scaled up the model by a factor of 5.8 compared with the original size. Similitude theory was applied to ensure comparability of the flow distribution between the device of original size and the scaled-up model. We focused our flow investigation on an area (20 × 70 × 43 mm) in a corner of the model with a Stereo-PIV setup. PIV data was compared to CFD data of the original sized artificial lung. From experimental PIV data, we were able to show local flow acceleration and declaration in the fiber bundle and meandering flow around individual fibers, which is not possible using state-of-the-art macroscopic CFD simulations. Our findings are applicable to clinically used artificial lungs with a similar stacked fiber arrangement (e.g., Novalung iLa and Maquet QUADROX-I). With respect to some limitations, we found PIV to be a feasible experimental flow visualization technique to investigate blood-sided flow in the stacked fiber arrangement of artificial lungs.
authors.affiliation: Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Kaesler
authors.affiliation: Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Schlanstein
authors.affiliation: Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Hesselmann
authors.affiliation: Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Büsen
authors.affiliation: Institute of Aerodynamics, RWTH Aachen University, Aachen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Klaas
authors.affiliation: Institute of Aerodynamics, RWTH Aachen University, Aachen, Germany.
authors.forename: Dorothee
authors.initials: D
authors.lastname: Roggenkamp
authors.affiliation: Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Schmitz-Rode
authors.affiliation: Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Steinseifer
authors.affiliation: Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany.
authors.forename: Jutta
authors.initials: J
authors.lastname: Arens
mesh_terms: D001783:Blood Flow Velocity; D003198:Computer Simulation; D004867:Equipment Design; D006439:Hemodynamics; D006801:Humans; D057446:Hydrodynamics; D008168:Lung / Q000098:blood supply*; D008955:Models, Cardiovascular; D010107:Oxygenators, Membrane; D012212:Rheology / Q000379:methods*; D012122:Ventilators, Mechanical
keywords: -Artificial lung; -Computational fluid dynamics; -Experimental flow visualization; -Hollow fiber membrane; -Oxygenator; -Porous media; -Stacked fiber configuration; Particle image velocimetry