抗振条-传热管大间隙多跨直管束流致振动试验研究

针对抗振条-传热管大间隙的4跨传热管直管束开展了流致振动试验研究。传热管束转角正三角形排列，3处抗振条将直管束分为4跨，中间其中1跨的局部区域受到横向流体的冲刷。试验测试获得了管间流速在3.3～14.7 m/s区间内传热管振动位移和振动频率响应特性。结果表明，随着管间流速逐渐增大，传热管在来流方向和升力方向的振动频率依次增大，传热管的振动模态从抗振条1处有效支撑、2处未有效支撑的状态，转换为3处抗振条均有效支撑的状态。试验观测到传热管流弹失稳，其临界流速为14.5 m/s，与5种经验关系式预测结果的对比表明，Chen关系式能较好地预测流弹失稳的发生，预测结果较保守，与试验值间的相对偏差为21.4%。

Experimental Investigation of Flow Induced Vibration of Multi-span Straight Tube Bundle with Large Gap AVB Support

Flow induced vibration of a four-span tube bundle with large gap anti-vibration bars (AVB) supports was experimentally studied. The tube bundle was arranged in rotated triangular pattern. Three AVB supports divided the straight tube bundle into four spans. Only part of one of the middle span tubes was subjected to cross flow. The response characteristics of the displacement and frequency of the heat transfer tube with the pitch velocity in the test increased from 3.3 m/s to 14.7 m/s were obtained. The results show that the vibration frequency increases with the pitch velocity in streamwise direction and transverse direction in proper order. The vibration mode of the tube changes from the state of one effective AVB support and two ineffective AVB supports to the state of three effective AVB supports. The fluidelastic instability (FEI) critical velocity for the tube tested is 14.5 m/s. Five empirical correlations were used to predict the FEI critical velocity, and the predicted results were compared with the experimental results. It is found that the Chen correlation is best. The predicted FEI critical velocity by Chen correlation is conservative, and the relative deviation from the experimental value is 21.4%.