斜底环形水箱一阶晃动模态参数的试验和理论识别

EXPERIMENTAL AND THEORETICAL IDENTIFICATIONS OF THE FIRST SLOSHING MODAL PARAMETERS FOR THE ANNULAR TANKS WITH INCLINED BOTTOM

三代核电工程中的安全壳顶端的冷却水箱是紧急情况下的重要冷却设施,其动力特性与抗震性能备受关注,关于这类特殊的斜底环形水箱,目前尚未见液体晃动模态参数的试验识別研究。通过制作平底、35°斜底、45°斜底和60°斜底四个环形水箱,采用人工激励的方法激出水箱内液体的一阶晃动,分别测量了不同水深下液体自由表面的波高衰减历程,从而确定了一阶晃动频率和阻尼比系数;建立了相应的ANSYS有限元模型,计算对应工况的一阶晃动频率与振型,测得的晃动频率与数值计算结果吻合良好,表明试验与理论识别方法合理有效。

In the Gen-III nuclear engineering, the cooling water tank on the top of the containment is an important cooling facility in case of an emergency. The dynamic characteristics and seismic behavior of the tank have attracted much attention. For the annular tank with an inclined bottom, the experimental identification for modal parameters of sloshing fluid has not been found in the public literature. In the paper, four annular tanks with different bottom slopes, which are flat bottom, 35 degree, 45 degree and 60 degree bottom annular tanks, respectively, were constructed for experiment. The first sloshing modes in annular tanks with different water depths are artificially excited , and the decay curves of wave height on liquid free surface were measured by using the laser displacement sensor. Thus the first sloshing frequencies and the damping ratios were obtained. The corresponding (ANSYS) finite element models were constructed and the first sloshing modes were calculated, respectively. The measured frequencies agreed well with the calculated results. It was indicated that the present theoretical and experimental identification methods were valid.