INVESTIGATION OF FLOW BEHAVIOR AND GAS TRANSFER PERFORMANCE OF AN OXYGENATOR WITH COMPUTATIONAL FLUID DYNAMICS(CFD)

Abstract

It is difficult to predict the performance of oxygenators in theoretically because of the complication of blood flow behavior in the woven hollow fibers and nonlinear blood-gas reaction. We have been trying to calculate blood-gas transfer numerically with CFD. In this study, we analyzed O2 and GO2 concentration in a computational model. In this model, we used the Reynolds number(Re) between 0.4 and 3.9 Reactions of O2 and CO2 with blood were modeled as functions of mass concentration. Numerical analysis was executed with these reaction models as source terms in mass transfer equation. A micro passage model was made of staggered four cylindrical hollow fibers which had 165 μm inner diameter, 225 μm outer diameter and 4.75 mm length in a rectangular parallelepiped. A small oxygenator model consisted of a hundred of micro passage models and its membrane area was 6.7 cm2. In a result of a micro passage model, a laminar blood flow along hollow fibers was shown and there was no obvious eddy under Re=3.9. A state of effective mass transfer without film resistance could be observed in a low Re blood flow. In a result of a small oxygenator model, O2 and CO2 transfer rates were 24.6 mL/min and 3.8 mL/min, respectively. The use of our proposed numerical analysis methods could bring a result of states of O2 and CO2 concentration in a micro passage and a result of O2 and CO2 transfer rate.