Vibration Characteristics of Multiple Conical Spiral Tube Bundles in Heat Exchangers

Elastic tube bundles are universally used in heat transfer enhancement via the flow-induced vibration in heat exchangers, and the study of the tube vibration characteristic is essential. The natural vibration of multiple conical spiral tube bundles was discussed in this paper based on numerical simulation. The substructures of ten conical spiral tubes, the inlet and the outlet branch were set up individually. Then the mass matrix and the stiffness matrix of these substructures were calculated. The general matrices were obtained and the vibration equation of the overall structure was founded. The results show that the natural frequencies of the multiple conical spiral tube bundles are smaller than the traditional planar elastic tube bundles and each natural vibration mode has a frequency band, which contains several natural frequencies.