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Experimental investigation of the internal tube flow effect on the vibration response of tubes in a shell and tube heat exchanger

In shell and tube heat exchangers, tube bundles often fail due to flow-induced vibrations. In the current study, the vibration response of tubes, placed in the first and third rows of the tube bundle, has been examined having a normal triangular arrangement with a pitch-to-diameter (P/D) ratio of 1.44. Each tube was tested at three different internal flow velocities of 0.85, 0.9, and 1 m/s and five shell-side velocities ranging from 0.9 to 1.3 m/s with an increment of 0.1 m/s. This is the first experiment of its kind that offers insight into the vibration behavior of the glass tubes of a shell and tube heat exchanger. Experimental analysis shows that tubes with internal flow vibrate with higher amplitudes than tubes without internal flow. Furthermore, the vibration amplitude of the tube tends to rise with increasing internal tube velocity, even for the same shell-side velocity. For the current range of shell- and tube-side velocities, with the internal flow from the tube, the hydrodynamic mass of the tube increases significantly with enhanced damping and contributes toward the stability of the tubes in cross-flow, the stability threshold is delayed and higher shell-side velocities are allowed to enhance the heat transfer rate.