Mass transfer coefficients in commercial modules, including blood oxygenators, agree with literature correlations at high flows but are smaller at low flows. The smaller values at low flows probably result from channelling in the hollow fiber bundle. For the special case of flow within the fibers, the slight polydispersity of the hollow fibers causing this channelling can be used to predict deviation from the Lévêque limit. These deviations can not be predicted from extensions to the Lévêque analysis, or the analysis by Graetz. For the special case of flow outside the fibers, the mass transfer coefficients in commercial modules of various geometries are surprisingly similar, and fall below those of carefully handmade modules. These results can be used to develop still better membrane module designs.
Bibliographical noteFunding Information:
Voorhees (Cobe Cardiovascular, Inc. ) James McCabe (Bard), Ron Leonard (Sarnes 3M), and Jean Pierson (Medtronic) provided the modules used in this work. We benefitted from discussions with Ravi Prasad (Hoechst-Ce-lanese) , Marc Voorhees (Cobe Cardiovascular, Inc. ) and Wallace Jansen (Minntec ) . The work was largely supported by Hoechst-Celanese. Other support came from the National Science Foundation (grant CTS 89-12634), from General Mills, and from the Center for Interfacial Engineering.
- blood oxygenators
- mass transfer
- membrane modules