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Harm of tube bundle vibration: 1. Vibration of the heat exchanger tube bundle can lead to collisions between the edge tubes and the shell, or between adjacent heat exchange tubes, resulting in wear at the areas where the tubes collide; thin sections of the tube walls may even crack as a result； 2. Due to the gap between the heat exchange tubes and the baffle plates, vibrations of the tube bundle generate high-intensity stresses similar to those produced by a saw, causing the heat exchange tubes to fail or break as a result of shear stress ； 3. Due to tube bundle vibration, the welds at the joints between the heat exchange tubes and the tube sheet are prone to fatigue failure, resulting in leakage at those joints ； Mechanisms of tube bundle vibration: The causes of tube bundle vibration mainly include four mechanisms, namely fluid elastic instability, vortex shedding, turbulent vibration, and acoustic resonance. The first three mechanisms can lead to tube bundle vibration, while acoustic resonance generates intense noise but generally does not cause tube bundle vibration. The locations most prone to damage due to fluid-induced vibration: 1. The unsupported middle span with the largest distance between two baffle plates in the tube bundle ； 2. Tubes around the bundle in the arc-shaped baffle opening area ； 3. The U-shaped bend of the U-tube bundle ； 4. Pipe below the shell-side inlet port ； 5. Tubes in the bypass flow around the tube bundle and in the flow channels of the partition plates in the tube side ； If vibration occurs during the design of the heat exchanger, the anti-vibration measures that can be taken include: 1. Reducing the flow velocity. Specific measures: ① Increasing the tube center distance ； ② Change the arrangement angle of the tube bundle ； ③ Install anti-impact baffles or guide cylinders ； 2. Changing the natural vibration frequency of the tube. Specific measures: ① Reduce the unsupported span of the baffle; the unsupported span is an important factor affecting fluid vibration. The shorter the unsupported span, the less likely the tube is to vibrate. Under the same shell-side flow rate and pressure drop, using multiple arc-shaped baffles can significantly reduce the unsupported span compared to conventional single-arc-shaped baffles ； ② Increase the diameter and wall thickness of the heat exchange tubes to raise their moment of inertia ； ③ By changing the material of the heat exchange tubes and increasing their elastic modulus, ferritic and austenitic stainless steels possess a higher elastic modulus than aluminum, brass, and similar materials ； ④ For U-tube heat exchangers, slats or rods are inserted into the gaps between the heat exchange tubes, and support plates are placed near the straight tube sections ； ⑤ No pipes are placed at the gaps in the baffle plates; NTIW-type baffle plates are used ； 3. Install sound-dampening baffles: Longitudinal baffles or perforated plates parallel to the tube axis can be placed in the shell side ； 4. Suppressing periodic vortices: Specific measures: ① Wrapping metal wire around the circumference of the heat exchange tubes, or installing metal strips along the axial direction, can alter the flow field and suppress or reduce periodic vortices ； ② Use baffle rods in place of traditional baffle plates ； 5. Others: ① Removing the heat exchange tubes along the cut line of the baffle can eliminate potential vibration ； ② Reducing the gap between the heat exchange tubes and the baffle plates and increasing the thickness of the baffle plates can effectively reduce the shear force acting at the junctions between the heat exchange tubes and the holes in the baffle plates ； ③The axial compressive load generated on the heat exchange tubes due to pressure and temperature can have a potentially adverse effect on vibration, especially in single-pass fixed-plate heat exchangers with hot fluid flowing in the tube side and in all multi-pass fixed-plate heat exchangers; in such cases, the use of expansion joints can effectively reduce the compressive stress on the heat exchange tubes ； ④ Avoid baffle notches that are too large or too small, as they can lead to uneven flow velocity distribution and localized high flow speeds, thereby inducing vibrations ； ⑤ Maintain a uniform baffle spacing ； ⑥Solid pipes are used in place of the original branch pipes to provide support and reduce vibrations ； ⑦If changing the shape of the housing is allowed, the E type can be changed to X or J type ；