基于HHT法的流化床内二元颗粒混合状态转变特性研究

在冷态流化床试验装置上,基于Hilbert-Huang变换法,研究流化床内载氧体与污泥二元颗粒混合状态的转变特性,获得相应的完全混合临界速度。实验结果表明:二元颗粒床层压降随风速增大分为完全分离、过渡混合与完全混合3个阶段。完全分离阶段高频段能量最大,约占70%。过渡混合阶段,随风速增大中频段能量逐渐增大到70%,而高频段能量迅速降低到约20%。完全混合阶段高、中、低3个频段能量均不随风速增大而变化。随着污泥加料量的增加,完全混合临界速度由0.57m/s增大到0.65m/s。与常规压降分析法相比,HHT法易于确定完全混合临界速度,具有使用数据量少,分析速度快的优点。

Study on Mixing Transition Characteristics of Binary Particles in a Fluidized Bed Based on Hht Method

The mixing transition characteristics of oxygen carrier and dried sludge binary particles were studied in a cold fluidized bed based on the Hilbert-Huang transform method, and the transition velocity of complete mixing state was obtained. Experimental results showed that the pressure drop of binary particles includes complete separation stage, transitional mixing stage, and complete mixing stage. In the complete separation stage, the spectral energy of high-frequency band is the largest, accounting for about 70%. In the transitional mixing stage, the spectral energy of middle-frequency band gradually increases to 70% with increase of wind velocity, while the spectral energy of high-frequency band rapidly decreases to about 20%. The spectral energies of high, medium and low frequency change little at higher wind velocities. With increase of sludge feeding amount, the transition velocity of complete mixing state increases from 0.57 m/s to 0.65 m/s. Compared with the conventional pressure drop analysis method, HHT method is easy to determine the transition velocity of complete mixing state. It also has the virtues of small data bulk and fast analysis processing.