Computational modeling of turbulent heat transfer in plate fin and tube heat exchangers

ABSTRACT PhD THESIS COMPUTATIONAL MODELING OF TURBULENT HEAT TRANSFER IN PLATE FIN AND TUBE HEAT EXCHANGERS Azize AKKOCA DEPARTMENT OF MECHANICAL ENGINEERING INSTITUTE OF NATURAL AND APPLIED SCIENCES UNIVERSITY OF ÇUKUROVA Supervisor : Prof. Dr. Beşir ŞAHİN Year: 2004, Pages: 230 Jury : Prof. Dr. Beşir ŞAHÎN : Prof. Dr. Hüseyin YAPICI : Prof. Dr. Orhan BÜYÜKALACA : Assist. Prof. Dr. Hüseyin AKILLI : Assist. Prof. Dr. Mustafa TUTAR Knowledge of thermo-hydraulic fundamentals for plate fin and tube heat exchangers is necessary to successfully carry out thermal design such as heat transfer and pressure drop data. In order to provide an optimum solution of these type of heat exchangers, Computational Fluid Dynamics (CFD) and Computational Heat Transfer (CHT) techniques are applied by employing both laminar and turbulence models. In the first part of the study, the present finite volume based laminar modeling technique is tested and validated against experimental results in terms of heat transfer and pressure drop performance of the heat exchanger under laminar flow conditions. In the second part, in order to investigate the effect of turbulence on the present flow, turbulence model simulations are carried out using both time averaged and space filtered Navier Stokes Equations based turbulence models and the best turbulence model was chosen as Large Eddy Simulation (LES) in comparison with the experimental data on the basis of the fluid flow and heat transfer calculations. In the last part of the study, in order to consider time and s pace variations of turbulence effects, a dynamic LES method based on Yoshizawa is adapted for the present calculations to improve the capability of the model. The validation of the present numerical model is tested against the experimental data selected from the literature and finally it is verified by using Particle Image Velocimetry (PIV) technique. Keywords: Computational Fluid Dynamics (CFD), Computational Heat Transfer (CHT), Plate Fin and Tube Heat Exchanger, Large Eddy Simulation (LES), Particle Image Velocimetry (PIV)