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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Numerical Modeling of Three Dimensional Heat Transfer and Fluid Flow Through Interrupted Plates Using Unit Cell Scale

Get access (open in a dialog) DOI: 10.1615/IHTC15.pmd.009025
pages 6947-6963

Resumo

Interrupted-plate heat exchangers are used as regenerators for absorbing and releasing thermal energy such as in a Compressed Air Energy Storage (CAES) system in which the exchanger absorbs energy to cool the air being compressed. The exchanger features layers of thin plates in stacked arrays. In a given layer, the plates are parallel to one another and parallel to the exchanger axis. Each successive layer is rotated to have its plates be perpendicular to the layer below but still parallel to the exchanger axis. As flow passes from one layer to the next, new thermal boundary layers develop, beneficial to effective heat transfer. The interrupted-plate heat exchanger, also seen as a porous medium, demonstrates strong anisotropic behavior when flow approaches the plates in a direction other than axially. Pressure drops and heat transfer coefficients are dependent upon the attack angle. Mathematical models for anisotropic pressure drop and heat transfer are proposed based on numerical calculations on a Representative Elementary Volume (REV) that represents a unit cell of the interrupted-plate medium. The anisotropic pressure drop is modeled by the traditionally used Darcy and inertial terms, with the addition of another term representing mixing effects. Heat transfer between the fluid and plates is formulated in terms of Nusselt number vs. Reynolds number and approach angle of the mean flow. These models can be used when solving, on the global scale, the volume-averaged Navier-Stokes equations for flow through the interrupted-plate array, by assuming that the porous medium region is a continuum. The global-scale analysis is used for the design and optimization of the medium.