空间弯管管束固有频率及附加质量系数计算

在工程设计过程中，合理确定中间热交换器内空间弯管的固有频率和附加质量系数，对于该设备的安全稳定运行至关重要。本文旨在通过有限元方法计算中间换热器同心圆排布的管束在空气和液钠环境中的固有频率及附加质量系数。将管束分为3个典型区域，选取6个位置建立换热管和流体域的三维模型，计算换热管的固有频率和附加质量系数。结果表明，换热管在空气中的固有频率受空间弯管的弯曲半径影响较小，附加质量系数受空间弯管的弯曲半径和所处区域位置影响较大，近似三角形排布区域的管束固有频率最低，该区域内层换热管的附加质量系数最大。 

Calculation of Natural Frequency and Added Mass Coefficient of Spatial Bend Tube Bundle

It is a crucial step for the safe and stable operation of the intermediate heat exchanger to determine the reasonable values of natural frequencies and added mass coefficients of the spatial bend tubes?during the engineering design process. This work aims to?calculate the natural frequencies and added mass coefficients?of the concentric spatial bend tubes of the intermediate heat exchanger in air and liquid sodium by finite element method. The concentric tube bundle was divided into three typical areas. For these typical areas, three-dimensional models of heat exchanger tubes and fluid fields were built to calculate the natural frequencies and added mass coefficients at six places. The results show that the natural frequency of the heat transfer tubes in the air is less affected by the bending radius of the spatial bend tube, while the added mass coefficient is greatly affected by the bending radius of the spatial bend tube and the place in which it is located. The tubes located in the approximate triangular arrangement place have the lowest natural frequency and the highest added mass coefficient.