NUMERICAL SIMULATION OF THE FLOW AND HEAT TRANSFER IN FINNED TUBE HEAT EXCHANGER

U radu je opisan cijevni orebreni izmjenjivač topline. Na osnovu poznatih ulaznih podataka i geometrije izmjenjivača i rebara napravljen je 3D model koji je zatim variran s obzirom na geometriju rebara i Reynoldsove brojeve. Za CFD simulaciju korišten je ANSYS Workbench programski paket. Na osnovu dobivenih rezultata temperature izlaznog zraka pokazano je koja geometrija rebra najviše doprinosi izmjeni topline. Dobiveni rezultati su uspoređeni s korelacijama za pad tlaka i koeficijente prijelaza topline. Uspoređen je laminarni model strujanja s k – ε modelom strujanja na istoj mreži te je prikazana točka odvajanja strujanja .Circular finned tube heat exchanger was described in this work. Based on the known input data and the geometry of the exchanger and the fins, a 3D model was created, which was then varied with respect to the geometry of the fins and the Reynolds numbers. For the CFD simulation, the ANSYS Workbench software package was used. On the basis of the obtained results of the output air temperature, it was shown which fin geometry contributes most to heat exchange. The obtained results were compared with the correlations for pressure drop and heat transfer coefficients. Laminar flow model was compared with k – ε turbulence model and the point of flow separation is shown