Department of Chemical Engineering, Oregon State University, 103 Gleeson Hall, Corvallis, OR 97331, USA.
Biomed Microdevices. 2012 Jun;14(3):595-602. doi: 10.1007/s10544-012-9638-7.
Two flat-plate microchannel hemodialyzers were constructed consisting of two identical laminae separated by a 20[μm] thick ultrafiltration membrane (Gambro AN69). Each lamina contains a parallel array of microchannels 100[μm] deep, 200[μm] wide, and 5.6[cm] or 9.9[cm] in length respectively. Urea was removed from the aqueous stream containing 1.0[g] urea per liter de-ionized water in the blood side, by countercurrent contact with pure de-ionized water in the dialysate side of the flat-plate hemodialyzer. In all cases volumetric flow rate of water in the dialysate side was equal or less than the volumetric flow rate in the blood side, which is in large contrast to commercial applications of hollow-fiber hemodialyzers where dialysate flow is severalfold larger than blood flow rate. A three-dimensional finite volume mass transport model, built entirely from the first principles with no adjustable parameters, was written in FORTRAN. The results of the mathematical model excellently predict experimental results. The fractional removals of urea predicted by the model are within 2.7%-11% of experimentally obtained values for different blood and dialysate velocities/flow rates in microchannels, and for different transmembrane pressures. The overall mass transfer coefficient was calculated using the urea outlet concentrations obtained at various average velocities (1.0-5.0[cm/s]) in the blood and dialysate, and two nominal transmembrane pressures (∆P(tm) = 0 and 10,000.[Pa]). Overall mass transfer coefficients obtained experimentally ranged from 0.068 to 0.14 [cm/min]. The numerical model predicted an average overall mass transfer coefficient of 0.08 [cm/min]. This value is 60% higher than those found in commercial dialyzers (~0.05[cm/min]).
构建了两个平板微通道血液透析器，由两个相同的薄片组成，薄片之间夹着一层 20μm 厚的超滤膜（Gambro AN69）。每个薄片包含一个平行排列的微通道阵列，深度为 100μm，宽度为 200μm，长度分别为 5.6cm 或 9.9cm。在血液侧，含有 1.0g 尿素/升去离子水的水溶液中，通过与平板血液透析器透析侧的纯去离子水逆流接触，从水中去除尿素。在所有情况下，透析侧水的体积流速均等于或小于血液侧的体积流速，这与中空纤维血液透析器的商业应用形成了鲜明对比，在中空纤维血液透析器中，透析液的流速是血流速度的数倍。完全从第一性原理构建的、没有可调参数的三维有限体积传质模型，用 FORTRAN 编写。数学模型的结果非常好地预测了实验结果。对于不同的血液和透析液流速/流量以及不同的跨膜压力，模型预测的尿素去除分数在实验获得值的 2.7%-11%范围内。使用在血液和透析液中的不同平均速度（1.0-5.0cm/s）获得的尿素出口浓度以及两个标称跨膜压力（∆P(tm)=0 和 10,000.[Pa]）计算总体传质系数。通过实验获得的总传质系数范围为 0.068 至 0.14 [cm/min]。数值模型预测的平均总传质系数为 0.08 [cm/min]。这个值比商业透析器（~0.05[cm/min]）高 60%。
