Effect of Fin Geometry on Flow-Induced Vibration Response of a Finned Tube in a Tube Bundle

An experimental study is carried out on a parallel triangular finned tube array with P/Deff ratio 1.62 to examine the effect of fin geometry on flow-induced vibration response. Fins on a tube increase the heat transfer rate but these also affect the fluid dynamics around the tube. The flow pattern across the finned tubes is complex as compared to bare tube arrays. There are numerous parameters that affect the finned tube vibration subjected to air cross-flow in a tube array. In the current study, some of these parameters i.e. fin thickness and fin density are focused and their effects on flow-induced vibration response are analyzed in different rows of fin tube array. The current experimentation is performed in a subsonic wind tunnel using a single flexible Aluminum finned tube in a rigid array. Seven tubes with similar specifications but distinct fin thickness and fin density are used for the testing purpose. Their amplitude response suggests that the flow-induced vibration behavior is greatly affected by changing the finned tube parameters. It has also been observed during spectral analysis that the Strouhal number is independent of fin geometry since it remained constant in different rows of the array for finned tubes under study. It suggests that the vortex shedding has also contributed towards the finned tube vibration predominantly in the first, second and the fourth row of tube array.