介绍了以最低子系统的固有频率作为U形换热管系统固有频率的2种计算方法和1种直接计算U形管全系统固有频率的方法,分析了跨数和端跨长度对U形换热管系统频率常数的影响.结果表明,对称支承条件下一定参数范围内跨数对频率常数的影响较大.提出了采用直接计算U形管全系统固有频率、利用跨数为3和7的U形管最低固有频率为基准作出的频率常数图以及U形管的支承方式、跨数、端跨长度等参数确定U形管最低固有频率的方法.采用此法的计算结果与实验值的误差为1.74％～4.29％,与有限元软件的计算结果相比误差为1.27％～6.26％.%Two calculation methods using the lowest subsystem frequency are introduced as the natural frequency of U-tube system, and a direct method for calculating the frequency of total U-tube system is given. The influence of span number and end span length to the U-tube system frequency were analyzed. The result showed that the span number has a considerable influence on frequency for symmetrical U-tube of certain parameter. Therefore a direct calculation method was given, using the frequency constant map based on three-span U-tube and seven-span U-tube. The frequency constant was determined according to support style, span number, end span length. The error for experiment data adopting this method was 1. 74% ~4. 29% and was 1. 27% ~ 6. 26% for the data from finite element method.
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