Simplified calculation method for hydrodynamic noise of multi-tube heat exchanger based on acoustic cavity model

Abstract

Because of the complex structure of the heat exchanger, its hydrodynamic noise simulation is difficult and the problem of low computational efficiency can not be solved well. An acoustically simplified calculation method for a large shell and tube heat exchanger with 2000 heat transfer tubes is proposed for a multi-tube number heat exchanger. The heat exchanger tubes are equated to different numbers of heat exchanger tubes according to their through-flow areas of 2000 heat exchanger tubes. Based on the LMS Virtual.Lab acoustic finite element module, acoustic cavity model calculations and analysis are performed for heat exchangers with different numbers of heat transfer tubes. From the acoustic cavity model laws of heat exchangers with 20, 100, 500 and 1000 tubes, it can be found that the distribution of vibration patterns and the intrinsic frequencies of heat exchangers with different tube numbers are similar. Therefore, the calculation model of 20 heat exchanger tubes is selected for noise calculation based on the fluid calculation software ANSYS-CFX and the acoustic calculation software ACTRAN. Based on the results of the noise calculation and the comparison verification of the experimental data, it is concluded that the heat exchanger models with similar acoustic cavity model have similar sound pressure levels. In addition, the sound transmission loss law and the contribution of the acoustic cavity model of the shell and tube heat exchanger are analyzed. Therefore, the effectiveness of the simplified calculation method of multi-tube number heat exchanger proposed is verified. The proposed simplified calculation method can be used to reduce the calculation difficulty and improve the calculation efficiency of complex heat exchangers.