Laminar flow and heat transfer in a quasi-counter flow parallel-plate membrane channel (QCPMC)

A parallel-plate membrane contactor with side inlets and side outlets has been designed and used for air humidity control. The contactor is comprised of a series of quasi-counter flow parallel-plate membrane channels (QCPMC). The laminar flow and heat transfer in the QCPMC are investigated based on a unit cell including one membrane and half of the channel. The equations governing the momentum and heat transports are established together with a uniform wall temperature boundary condition and numerically solved by a finite volume difference approach. The mean product of friction factor and Reynolds number (fRe) and Nusselt number (Num) are then obtained and numerically validated by those taken from other well-known publications. Influences of the Reynolds numbers (Re), entrance ratios (xin/x0), aspect ratios (x0/H), and various fluids with different Prandtl numbers (Pr) on the (fRe)m and Num are obtained and analyzed. It can be found that a distinct vortex is generated for the water stream flowing through the QCPMC when the Re is greater than 100. Further, for the same x0/H, the Num of the LiCl stream is the largest, and next the water stream, the least the air stream.