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对汽轮发电机组弹簧隔振基础进行模型试验的最根本理论是相似理论,最关键的技术是模态分析。本文利用相似理论与模态分析的传递函数矩阵方程,推导了强迫振动模型试验的相似准则方程,确定了r阶模态的决定性相似准则为r阶阻尼比Dr与r阶调谐比ηr,非决定性相似准则为振动线位移组合量。对百万千瓦级半速核电站汽轮发电机组弹簧隔振基础的强迫振动进行模型试验时,各阶模态的阻尼比与调谐比必须相等,但是模型与原型的各阶阻尼比是否能够做到相等,缺乏验证。而且目前阻尼比取值不太合理,模型试验没有给出有益的建议。振动系统包括汽轮发电机组、基础台座、弹簧隔振器与阻尼器等,模型试验在机器的激振频率、激振力强度与分布等方面难于满足相似理论。模型试验在满足弹簧隔振器的刚度、压缩量与系统频率要求时也有困难。
The most fundamental theory of the model test of the spring vibration isolation foundation of the steam turbine generator set is the similar theory. The most crucial technique is modal analysis. In this paper, we use the transfer matrix equation of similar theory and modal analysis to deduce the similarity criterion equation of forced vibration model test, and determine the decisive similarity criterion of r-order modal as r-th damping ratio Dr and r-order tuning ratio ηr, nondeterministic Similar criteria for the vibration line displacement combination. When the model test of forced vibration of the spring vibration isolation foundation of a 1 000MW half-speed nuclear power plant is carried out, the damping ratio and the tuning ratio of each mode must be equal, but whether the damping ratio of each order of the model and the prototype can be achieved Equal, lack of verification. At present, the damping ratio is not reasonable, and the model test does not give useful suggestions. The vibration system includes the turbine generator set, foundation pedestal, spring isolator and damper, etc. The model test is hard to meet the similar theory in terms of machine excitation frequency, intensity and distribution of exciting force. Model tests also have difficulties in meeting the stiffness, compression and system frequency requirements of spring isolators.