A cross flow hollow fiber membrane bundle is used for liquid desiccant air dehumidification. The turbulent fluid flow and conjugate heat and mass transfer across the bundle considering interactions between neighboring fibers are investigated. In the bundle, the process air flows across the fiber bundle and salt solution flows inside the fibers packed in the shell. Heat and moisture are exchanged through the membranes. Two structured arrangements: in-line and staggered, are considered. Due to the periodicity of the fluid flow and heat and mass transfer across the bundle, two representative periodic unit cells which include 2-3 neighboring fibers simultaneously, are selected as the calculation domains. Turbulence in the shell side is considered. The governing equations for fluid flow and heat and mass transfer in tube side, membrane side, and shell side are coupled together and solved numerically with a self-built code. The fundamental data of friction factor, Nusselt and Sherwood numbers on both the tube and the shell sides are then obtained and experimentally validated. (C) 2013 Elsevier Ltd. All rights reserved.