Characterization of Microchannel Hemodialyzers Using Residence Time Distribution Analysis

Abstract

Microchannel-based hemodialysis has a potential to improve survival rates and quality of life for end-stage renal disease patients compared to conventional hemodialysis technology. Characterization of hydrodynamic behavior in microchannel geometries is necessary for improving flow uniformity, a critical challenge in realizing a commercial device. A test loop was developed for measuring the impulse response of a tracer dye injected into a dialyzer test article for the purpose of developing residence time distributions (RTD) to characterize lamina design. RTD variance tended to lower for designs that are more dominated, volume-wise, by the microchannel array versus the headers. RTD results also emphasize how defect issues can significantly impact a microchannel device via discrepancies between conceptual and operational devices. A multisegmented CFD model, developed for pairing with the impulse response test loop and dialyzer, showed good agreement between visual observation of the tracer in simulations and experiments, and the shape and peak of the output profiles.

Characterization of an enzymatic packed-bed microreactor: Experiments and modeling

“…The mean residence time (τ), variance (σ 2 ) and skewness (s) of the distribution C glu (t) were calculated from the pulse-response measurements as stated in the literature [27]. The starting assumptions involved the closed vessel boundary conditions (the fluid enters and leaves the reactor only once and there is no recirculation), steady state flow, homogeneous system, an inert tracer which does not disturb the flow, and isothermal conditions [28].…”