An elliptical hollow fiber membrane bundle (EHFMB), which is installed in a shell to form a counter flow tube-and-shell heat exchanger like hollow fiber membrane contactor, is commonly used for air humidity control. EHFMB is usually randomly packed in practical applications because of the randomness in the assembly process. The longitudinal transport phenomena between a randomly distributed elliptical hollow fiber membrane bundle (REHFMB) are studied. To disclose the effects of the random distributions on the transport phenomena, a unit cell containing 20 fibers based on Voronoi tessellation technology and the air flowing axially between the REHFMB is selected as the calculating domains. The governing equations governing the fluid flow and heat transfer between the REHFMB are established and numerically solved. The friction factor and Nusselt number in the unit cell under various fiber distributions, packing fractions (phi), rotation angles (beta) and semiaxis ratios (b/a) are then obtained, analyzed, and experimentally validated. It can be found that the elliptical semiaxis ratios, the random distribution in positions, and rotation angles all have effects on the axial transport phenomena between the REHFMB. Further, the random distribution in positions is the dominant factor. (C) 2014 Published by Elsevier B.V.