Acoustic radiation and cold point defect in boiler tube arrays based on phononic crystals theory

The structure of heat exchangers is similar to two-dimensional phononic crystals in boilers. In this study, with the given tube array parameters of the heat exchanger, we investigate the effects of sound source location and different frequencies on acoustic radiation. Based on phononic crystals theory, the Plane Wave Expansion method is used to calculate the band gap structure, and the Finite Element method is used to study the acoustic insertion loss and radiation characteristics. In the simulations, constant boundary conditions are imposed on the boundary between the air and steel boards, the radiation boundary conditions are applied to all boundaries of the air domain cell, and the free triangular is used in the simulated domain. When there is tube leakage, a cold point defect exists in the tube arrays. We also study the sound transmission characteristics of the cold point defect at a different location. This study can provide an innovative concept and method for leakage location and sonic soot cleaning in boiler tube arrays.