锅炉换热器管壁声共振的模态分析

利用Helmholtz积分方程，研究了锅炉换热器一维管阵列壁面的声共振问题，给出了管壁振动与声波频率、管间距和管壁内、外流体载荷等参数之间关系的数学模型，数值计算了换热器管阵列在声波作用下激发管壁振动的模态共振频率分布特征及其速度振幅分布图案。结果表明多管之间多极子声散射的相互作用将对管壁运动的幅值产生影响，但对共振频率影响较小。管壁共振频率主要受到管外介质耦合质量的影响，因此置于水中的换热器(核电机组)管壁共振频率低于空气中换热器管壁(火电机组)的共振频率。

A MODAL ANALYSIS OF ACOUSTIC RESONANCE FOR CYLINDRICAL SHELLS OF HEAT-EXCHANGER IN BOILERS

In this paper, by using Helmholtz Integral Equation (HIE), a method to solve the resonance problem of sound waves scattered by one-dimension tube arrays in a boiler is presented. A mathematic model of tube wall vibration caused by sound wave has been given out. The model takes into account the sound frequencies, tube space, and inner/outer fluid loading. The resonance frequencies of the tube walls on multiple scattering are calculated at different modes. The patterns of radial tube wall motion depending on the mode number, the reduced frequency (ka) and the tube space (d/a) are shown. The tubes are set in boilers, there is water inside, and water or air is outside. The numerical results show that the interaction among the tubes due to the multiple scattering will drastically change the amplitude of the tube wall motion, but scarcely change the tube resonance frequency. The wall resonance frequency is mainly dependent on the coupling mass of the fluid medium out of the tubes, and therefore, the resonance frequency of the heat-exchanger tubes in water is lower than that in air.