hemofiltration(HF) and hemodiafiltration(HDF) in hollow fiber modules have been established as a generalized duct convective mass transfer model
in which the dialysis-filtration number is taken as the model parameter. A numerical solution of the model is obtained by using the orthogonal collocation method. The influence of some variables on mass transfer characteristics is discussed. The results obtained by orthogonal collocation are compared with those obtained by the finite-difference method and exact analytical solution. With regard to computing-time
the orthogonal collocation has an advantage over the finite-difference method.