Obtaining Closure for Heat Exchanger Modeling Based on Volume Averaging Theory (VAT)

Volume Averaging Theory (VAT) has been used to rigorously cast the point-wise conservation of energy, momentum and mass equations into a form that represents the thermal and hydraulic properties of heat exchanger channel morphology. At the lower level, the media is described by a representative elementary volume (REV). Closure terms in the VAT equations are related to a local friction factor and a heat transfer coefficient of the REV. The terms in the closure expressions are complex and are evaluated using scaling suggested by VAT from either experimental data or the output of a CFD code. The VAT equations for a finned tube heat exchanger are given and that the key parameters can be obtained by suitable scaling is demonstrated.