Numerical investigation on the heat transfer enhancement mechanism of planar elastic tube bundle by flow-induced vibration

This work numerically investigated the heat transfer enhancement mechanism of planar elastic tube bundle by flow-induced vibration based on a two-way fluid structure interaction model. The unsteady, three-dimensional incompressible Navier-Stokes equation was solved with finite volume approach and the dynamic equilibrium equation of tube bundle was solved with finite element method combined with dynamic mesh scheme. Then the heat transfer performance was studied according to the field synergy principle. Synergy angle and Nusselt number were studied qualitatively and quantitatively from overall and local perspectives. Results show that improvement of field synergy and oscillating relative velocity are two crucial factors for heat transfer enhancement. Among which, the improvement of field synergy plays a dominated role on heat transfer enhancement. At the water velocity 0.15 m/s, the overall average Nusselt number is increased by 6.5%, and the overall average field synergy is improved by 6.01% with the tube vibration within the sub-millimeter level. In view of the shell-side geometry and vertical arrangement of tube bundle, the flow-induced vibration is conducive to the heat transfer enhancement of top tube bundle. The maximum heat transfer augmentation of 11.43% occurs around the fifth row tube bundle, and the maximum improvement of field synergy is 10.9% around the third row tube bundle.