【摘要】 利用电容层析成像示踪大颗粒在床内运动轨迹,通过正交实验法研究非均匀布风流化床内球形重质大颗粒粒径、密度、流化风速对其在床内停留时间分布(residence time distribution,RTD)的影响规律。实验及显著性分析结果表明大颗粒停留时间随密度、粒径增大而增大,随流化风速增大而减小;大颗粒密度是影响其停留时间的主要因素,流化风速次之。由回归分析建立了大颗粒平均停留时间(mean residence time,MRT)和实验变量的无量纲经验关系式,将其用于预测一定工况下大颗粒MRT时误差不超过20%。最后采用Shapiro-Wilk正态性检验方法对RTD曲线进行检验,结果表明大颗粒在床内的停留时间很接近正态分布。更多还原

【Abstract】 A series of orthogonal experiments were conducted to study the influence of the superficial velocity and the size and density of the sphericallarge objects on their residence time distribution(RTD) in a cold lab-scale fluidized bed with uneven distribution of air. The RTDs were determined by electrical capacitance tomography(ECT) tracing technique.Significance analysis demonstrates that the object density is the dominant factor influencing the residence time, followed by the superficial velocity. Increasing fluidization velocity, object size or decreasing object density reduces the residence time.A dimensionless empirical relationship between the mean residence time(MRT) and the three influencing factors was established through regression analysis, and its prediction error was within 20%. Finally, ShapiroWilknormality test method was used to test the RTD and the analysis result shows that all of the RTD curves are near the normal distribution.更多还原