Characteristics of vibration displacement signals of graphite tube in fluidized bed evaporator

doi:10.11949/j.issn.0438-1157.20151541

Abstract

Abstract:

The characteristics of vibration displacement signals of graphite tube in vapor-liquid-solid (V-L-S) external circulating fluidized bed evaporator were investigated by means of accelerometers and a system of measurement and analysis of dynamic vibration signals using signal analysis tools of the standard deviation, power spectrum and wavelet transformation. Main results were as follows. The original and global vibration displacement signal with multi-scale behavior can be decomposed into low and middle vibration displacement signal (LFS/MFS) and high frequency vibration displacement signal (HFS). The standard deviation of the original signal (under V-L-S boiling flow) and its LFS/MFS by wavelet transformation increased at first and then a stable trend with increasing steam pressure, and its HFS by wavelet transformation showed a slight increasing trend. The addition of solid particles can weaken the vibration intensity of LFS/MFS and enhance the vibration intensity of HFS. The standard deviation of HFS represented an apparent increasing trend with the solid holdup. The standard deviation of three vibration signals (original, LFS/MFS, HFS) indicated a weak enhancement with solid particle diameter. The vibration behavior of graphite tube at different axial positions was also investigated. Two correlations of vibration intensity for vapor-liquid and V-L-S boiling flows were provided.

Key words: vapor-liquid-solid flow, graphite tube, evaporation, vibration displacement signal, multi-scale, safety

摘要：

借助振动传感器和静动态信号测试分析系统,采用标准偏差、功率谱和小波分解等方法,对汽液固三相外部自然循环流动沸腾流化床蒸发器中石墨管的振动位移行为进行了研究。结果表明:具有多尺度特性的原始完整的振动位移信号可以分解为低中频信号和高频振动信号;原始信号和低中频振动位移信号的标准偏差随加热蒸汽压力的增加先增加而后趋于稳定,高频振动信号则缓慢增加;在汽液两相系统中,颗粒的加入和流化抑制了石墨管的低中频振动行为,增强了高频振动行为;高频信号的标准偏差随固含率增加而显著增加;振动行为随粒径增大有所增强;研究了石墨管不同轴向位置处的振动规律;根据实验数据拟合得到了两相及三相条件下,石墨管振动强度的关联式。

关键词: 汽液固三相流, 石墨管, 蒸发, 振动位移, 多尺度, 安全

CLC Number:

AN Min, LIU Mingyan, XU Xiaoping. Characteristics of vibration displacement signals of graphite tube in fluidized bed evaporator[J]. CIESC Journal, 2016, 67(2): 530-539.

安敏, 刘明言, 徐晓萍. 流化床蒸发器中石墨管振动位移特性[J]. 化工学报, 2016, 67(2): 530-539.

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