An optimal design for hollow fiber heat exchanger: A combined numerical and experimental investigation

Abstract

Polymeric hollow-fiber heat exchangers are a sound alternative to metallic plate fin counterparts. Plastic heat exchangers weigh much less, have significantly larger surface area per unit volume, are corrosion/erosion resistant and electrically non-conductive, have a reduced ecological footprint, and are likely to be substantially cheaper.A good passive chilled beam type heat exchanger requires its heat transfer surfaces to be distributed in optimal positions so that the thermal performance is maximized. For that purpose, a Lattice-Boltzmann model was setup in the open-source code Palabos to calculate natural convection triggered around a chilled beam made of many parallel hollow fibers with cold water running inside. In the simulations, the horizontal and vertical pitches between fibers were varied to eventually find their dimensionless optima of 6.9 and 1.3, respectively, for the Rayleigh number of 2.3. The numerical results were validated in the experiment as well as in the well-established ANSYS FLUENT.