Mathematical modelling of the operation of cross-flow finned-tube heat exchangers / Anna Korzeń ; Politechnika Krakowska im. Tadeusza Kościuszki. – Kraków : Wydaw. PK, 2015. – 99 s. : il. (w tym ... więcej

Mathematical modelling of the operation of cross-flow finned-tube heat exchangers / Anna Korzeń ; Politechnika Krakowska im. Tadeusza Kościuszki. – Kraków : Wydaw. PK, 2015. – 99 s. : il. (w tym kolor.). – (Monografia / Politechnika Krakowska im. Tadeusza Kościuszki. Mechanika, ISSN 0860-097X). – Bibliogr. 40 poz., Streszcz., Abstr. – Tyt. streszcz.: Modelowanie matematyczne pracy krzyżowo-prądowych wymienników ciepła z rur ożebrowanych. – Seria gł.: Monografia / Politechnika Krakowska im. Tadeusza Kościuszki, ISSN 0860-097X ; 506

The objective of this work is modelling the steady- and unsteady-state operation of cross-flow heat exchangers made of finned tubes. A heat exchanger can be made of tubes with individual or continuous ... więcej

The objective of this work is modelling the steady- and unsteady-state operation of cross-flow heat exchangers made of finned tubes. A heat exchanger can be made of tubes with individual or continuous fins called lamellae. In contrast to previous studies, the unsteady-state temperature field distribution in the fin was taken into account. Fins may have a complex shape. A general method for the determination of the fins temperature field and efficiency in the unsteady state was developed. A new formula for the weighted average heat transfer coefficient that takes into account the heat transfer through the fins and surfaces of the tubes between them, as well as the heat accumulation inside the fins, was derived. A heat exchanger may have any number of passes and rows. Temperature-dependent changes in the physical properties of fluids can easily be taken into account. This is especially important for heat exchangers with large fluid temperature differences between the outlet and inlet. A mathematical model of a two-pass car radiator with two tube rows was constructed. Correlations for heat transfer coefficients were determined based on experimental tests performed for the analysed exchanger. Simulations were performed of the exchanger unsteady-state operation at time-dependent changes in the water volume flow and changes in the air flow velocity. The calculation results were compared with those obtained from experimental testing and a good agreement was found between them.