发表机构
Delft University of Technology（代尔夫特理工大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
提出一种60 GHz调频连续波雷达的随机多普勒测量框架，实现鼓泡流化床内距离分辨的双向颗粒运动观测，并通过统计谱分析提取速度与谱宽信息。
AI 中文摘要
本文解决了在光学不透明、致密鼓泡流化床内部观测颗粒运动的问题。差压测量能够识别整体流化状态，但无法揭示颗粒在何处运动或其速度如何随高度变化。在设施上方安装了一台商用60 GHz调频连续波雷达，以在无需光学窗口或侵入式探头的情况下获得深度分辨测量。每个测量的深度单元包含约600微米砂粒的集合，处于瑞利-米散射过渡区。颗粒位移、单元交换以及阴影变化会改变回波的相位和幅度。因此，它们的相干和是一个随机复信号，其协方差和多普勒谱描述了集合运动。一种统计谱分析在距离和时间上提取总功率、平均视线径向速度和多普勒谱宽。八分钟的测量揭示了一个可探测的扩展层以及朝向和远离雷达的交替运动。在充分发展的流化过程中，正负平均区域共存，并交换它们对颗粒功率的贡献。大多数可探测谱包含一个主多普勒瓣；少数子集支持两个可区分的瓣，包括一个负平均速度和一个正平均速度的情况。5秒总功率趋势与实测压降的相关系数为0.734，而局部拟合谱宽趋势的相关系数较弱，为0.152。这项工作开发了一种距离分辨的统计多普勒测量方法，能够揭示双向颗粒运动，并确定何时多个局部速度贡献是可区分的。
英文摘要
The problem of observing particle motion inside an optically opaque, dense bubbling fluidized bed is addressed. Differential-pressure measurements identify the bulk fluidization state but do not reveal where particles move or how their velocities vary with height. A commercial 60 GHz frequency-modulated continuous-wave radar is mounted above the facility to obtain depth-resolved measurements without optical access or an intrusive probe. Each measured depth cell contains an ensemble of 600 micrometre sand grains in the Rayleigh-Mie scattering transition region. Particle displacement, cell exchange, and changes in shadowing alter echo phases and amplitudes. Their coherent sum is therefore a stochastic complex signal, whose covariance and Doppler spectrum describe ensemble motion. A statistical spectral analysis retrieves total power, mean line-of-sight radial velocity, and Doppler spectral width over range and time. Eight-minute measurements reveal an expanding radar-detectable layer and alternating motion towards and away from the radar. Positive- and negative-mean regions coexist during developed fluidization and exchange their contribution to particle power. Most detectable spectra contain one dominant Doppler lobe; a small subset supports two distinguishable lobes, including cases with one negative and one positive mean velocity. The 5-s total-power trend has a correlation of 0.734 with measured pressure drop, whereas the local fitted spectral-width trend has a weaker correlation of 0.152. This work develops a range-resolved statistical Doppler measurement that reveals bidirectional particle motion and determines when multiple local velocity contributions are distinguishable.
Comments24 pages, 9 figures. Submitted to IEEE Transactions on Instrumentation & Measurement
