An optimal design for hollow fiber heat exchanger: A combined numerical and experimental investigation. (15th August 2021)

• Record Type: Journal Article
• Authors: Bohacek, Jan; Raudensky, Miroslav; Astrouski, Ilya; Karimi-Sibaki, Ebrahim
• Is Part Of: Energy. Volume 229(2021)
• Publication Date: 2021-08-15
• Subjects: Heat exchanger -- Chilled beam -- Natural convection -- Hollow fiber -- Optimization -- Computational fluid dynamics; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Energy consumption -- Periodicals; 333.7905
• DOI: 10.1016/j.energy.2021.120571
• Languages: English
• ISSNs: 0360-5442

Abstract

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. Highlights: A chilled beam cooling device made of thousands of polymeric hollow fibers. Configuration of water cooled fibers resembling inline tube banks placed in air. Optimization of inter-fiber pitches to attain maximal thermal performance. The horizontal pitch of substantially greater importance than the vertical pitch. Thermal Lattice Boltzmann simulation (D2Q9+D2Q5) verified with ANSYS FLUENT.