CAJ | 학술논문

对快速流化床内轴向动态压力进行了测量，分别通过标准偏差、功率谱以及多尺度小波分析研究了流化床内的动态特性。研究结果表明：压力脉动的强度沿轴向由下至上逐渐衰减，且在循环速率较高时，底部压力脉动标准偏差与顶部之间存在着明显的转折；压力信号的主频随着颗粒质量流率的增加，其所对应的峰值（即脉动强度）有所增加，而主频的频率逐渐降低。通过压力脉动的小波多尺度分析表明：流化床内压力脉动中，小尺度信号主要体现在由于气体与颗粒的湍动、颗粒碰撞、颗粒团聚物的形成与破裂等高频部分的信号；中尺度信号主要捕获来自于不稳定进料所引起的较大的压力脉动；大尺度信号与床层的宏观稳定性相关。研究结果表明，通过对动态信号的微观分析可以深入认识气固两相流的瞬态参数特性以及气固间的相互作用机制。
대쾌속류화상내축향동태압력진행료측량，분별통과표준편차、공솔보이급다척도소파분석연구료류화상내적동태특성。연구결과표명：압력맥동적강도연축향유하지상축점쇠감，차재순배속솔교고시，저부압력맥동표준편차여정부지간존재착명현적전절；압력신호적주빈수착과립질량류솔적증가，기소대응적봉치（즉맥동강도）유소증가，이주빈적빈솔축점강저。통과압력맥동적소파다척도분석표명：류화상내압력맥동중，소척도신호주요체현재유우기체여과립적단동、과립팽당、과립단취물적형성여파렬등고빈부분적신호；중척도신호주요포획래자우불은정진료소인기적교대적압력맥동；대척도신호여상층적굉관은정성상관。연구결과표명，통과대동태신호적미관분석가이심입인식기고량상류적순태삼수특성이급기고간적상호작용궤제。
Pressure fluctuations along the vertical direction of the gas-solid fluidized bed in the different conditions have been measured. Standard deviation analysis of pressure fluctuations revealed that the intensity of the pressure fluctuations decreased along the column upwards, and there’s an obvious turning point of the standard deviations curve between the bottom and upper area. The measurement was also extensively analyzed by using power spectral density and wavelet decomposition in addition to the standard deviation analysis. The dominant frequency of the pressure signal went up as the particle mass flux increased, and its corresponding power peak (fluctuation intensity) was also increased. With decoupling of the pressure signal based on multi-resolution analysis of wavelet transform, the pressure signal was separated into three scale sub-signals. It was found that the meso-scale sub-signal mainly captured the large fluctuations caused by clusters passing by, the micro-scale captured the small fluctuations interweaving in the dominant fluctuations which is probably produced by the particle-turbulence interaction, formation and breakup of the clusters, gas turbulence, or the slight oscillations of fast fluidized bed. And macro-scale signals with low frequency and amplitude of demonstrate macro-stability of the fluidizing system was a macroscopic overall unit. Therefore, with the microscope analysis on the dynamic pressure, instantaneous parameters characteristics of gas-solid flow and interaction between gas and solids in the fluidized bed could be well investigated.