A Numerical and Experimental Study of Mass Transfer in the Artificial Kidney

Abstract

To develop a more efficient and optimal artificial kidney, many experimental approaches have been used to study mass transfer inside, outside, and cross hollow fiber membranes with different kinds of membranes, solutes, and flow rates as parameters. However, these experimental approaches are expensive and time consuming. Numerical calculation and computer simulation is an effective way to study mass transfer in the artificial kidney, which can save substantial time and reduce experimental cost. This paper presents a new model to simulate mass transfer in artificial kidney by coupling together shell-side, lumen-side, and transmembrane flows. Darcy's equations were employed to simulate shell-side flow, Navier-Stokes equations were employed to simulate lumen-side flow, and Kedem-Katchalsky equations were used to compute transmembrane flow. Numerical results agreed well with experimental results within 10% error. Numerical results showed the nonuniform distribution of flow and solute concentration in shell-side flow due to the entry/exit effect and Darcy permeability. In the shell side, the axial velocity in the periphery is higher than that in the center. This numerical model presented a clear insight view of mass transfer in an artificial kidney and may be used to help design an optimal artificial kidney and its operation conditions to improve hemodialysis.

Effect of distribution tabs on mass transfer of artificial kidney

“…To reduce the number of grid nodes and improve the speed of convergence, and referring to reports of the simulation and experiment in the literature (Doleček and Cakl, 1998;Liao, 2002;Yang and Cussler, 1986), 19 hollow fibers were used in the module. The inner diameter and the outer diameter of the hollow fiber are 0.0028 and 0.0030 m, respectively.…”

Double porous media model for mass transfer of hemodialyzers

“…Geometric parameters of the modules and transport parameters of membranes are shown in Table 2 and According to the literature [1,8,19], saline solution and water were substituted for blood and dialysate, respectively. The solution properties adopted water properties at 310.15K.…”

“…For dialyzer modules containing thousands of hollow fibers, porous media model based on volume averaged technique, can describe transport phenomena within the modules effectively [11,14,15]. In the literature the shell side was usually treated as porous media region, while the lumen side seldom [16][17][18][19]. Labecki et al [20] and Lemanski and Lipscomb [11] treated the lumen side as porous media region to predict the redistribution of protein in the shell side and the production of nitrogen from air, respectively.…”

Two‐Dimensional Mass‐Transfer Model of a Flat‐Plate Dialyzer with Ultrafiltration Operation

“…However, for the hollow fiber system with ultrafiltration, the velocity distribution is more complex. Therefore, Liao et al [37] assumed the shell side of the hollow fiber module as a porous medium to simplify the problem and developed a two-dimensional mathematical model to simulate the mass transport in a hollow fiber artificial kidney.…”