An energy distribution theory was presented based on regular evolvement of energy fraction of acous-tic signals with fluidization velocity. Wavelet packet analysis was used in processing the acoustic sig-nals originat...An energy distribution theory was presented based on regular evolvement of energy fraction of acous-tic signals with fluidization velocity. Wavelet packet analysis was used in processing the acoustic sig-nals originated from particle impact on the wall of a fluidized bed. A new criterion of judging incipient fluidization(Umf) velocity and minimum turbulent velocity(Umt) was proposed according to the energy distribution theory. Experiments were performed with five groups of high density polyethylene(PE) particles and one bimodal PE to acquire incipient fluidization velocity and minimum turbulent velocity by using the criterion. The feasibility of this method in obtaining characteristic fluidization parameters was further verified by comparing it to results from the pressure drop method and the empirical value from industry.展开更多
在115 mm×1 000 mm 有机玻璃制成的圆柱型流化床中,对生物质焦、煤焦、煤灰及其混合颗粒的流化特性进行了实验研究。实验结果表明,单一生物质焦颗粒不能正常流化,煤焦和煤灰颗粒可以很好地流化。当煤焦和生物质焦混合颗粒中生物质...在115 mm×1 000 mm 有机玻璃制成的圆柱型流化床中,对生物质焦、煤焦、煤灰及其混合颗粒的流化特性进行了实验研究。实验结果表明,单一生物质焦颗粒不能正常流化,煤焦和煤灰颗粒可以很好地流化。当煤焦和生物质焦混合颗粒中生物质焦颗粒的质量百分比小于33%时,两者混合颗粒可以达到较好的流化状态,煤焦和生物质焦双组分混合颗粒的最小流化速度随生物质焦质量百分比的增加而减小。生物质焦和煤焦的混合体系中添加煤灰,流化质量可进一步提高,生物质焦、煤焦和煤灰三组分混合颗粒的最小流化速度随着煤灰质量百分比的增加而增大。双组分和三组分混合颗粒的最小流化速度和经验公式预测结果具有良好的一致性。展开更多
为数众多的计算颗粒最小流态化速度vmf的公式大体上分为3类:第1类以Ergun公式为基础,引入经验系数加以修正;第2类以某种流体力学关系为基础;第3类属于纯经验公式。这3种类型中,以第1类公式有较大范围之Ar适应性,比较适用。提出一种属于E...为数众多的计算颗粒最小流态化速度vmf的公式大体上分为3类:第1类以Ergun公式为基础,引入经验系数加以修正;第2类以某种流体力学关系为基础;第3类属于纯经验公式。这3种类型中,以第1类公式有较大范围之Ar适应性,比较适用。提出一种属于Ergun型的计算公式,从目前掌握的实验数据看来,比工程界广泛应用的Wen and Yu式用于计算液-固流态化系统有更高的精确性,最大偏差小于7.63%,均方差为5.27%,而且对球形与非球形颗粒都适用。展开更多
基金Supported by the National Natural Science Foundation of China (Grant No. 204090205)
文摘An energy distribution theory was presented based on regular evolvement of energy fraction of acous-tic signals with fluidization velocity. Wavelet packet analysis was used in processing the acoustic sig-nals originated from particle impact on the wall of a fluidized bed. A new criterion of judging incipient fluidization(Umf) velocity and minimum turbulent velocity(Umt) was proposed according to the energy distribution theory. Experiments were performed with five groups of high density polyethylene(PE) particles and one bimodal PE to acquire incipient fluidization velocity and minimum turbulent velocity by using the criterion. The feasibility of this method in obtaining characteristic fluidization parameters was further verified by comparing it to results from the pressure drop method and the empirical value from industry.
文摘在115 mm×1 000 mm 有机玻璃制成的圆柱型流化床中,对生物质焦、煤焦、煤灰及其混合颗粒的流化特性进行了实验研究。实验结果表明,单一生物质焦颗粒不能正常流化,煤焦和煤灰颗粒可以很好地流化。当煤焦和生物质焦混合颗粒中生物质焦颗粒的质量百分比小于33%时,两者混合颗粒可以达到较好的流化状态,煤焦和生物质焦双组分混合颗粒的最小流化速度随生物质焦质量百分比的增加而减小。生物质焦和煤焦的混合体系中添加煤灰,流化质量可进一步提高,生物质焦、煤焦和煤灰三组分混合颗粒的最小流化速度随着煤灰质量百分比的增加而增大。双组分和三组分混合颗粒的最小流化速度和经验公式预测结果具有良好的一致性。
文摘为数众多的计算颗粒最小流态化速度vmf的公式大体上分为3类:第1类以Ergun公式为基础,引入经验系数加以修正;第2类以某种流体力学关系为基础;第3类属于纯经验公式。这3种类型中,以第1类公式有较大范围之Ar适应性,比较适用。提出一种属于Ergun型的计算公式,从目前掌握的实验数据看来,比工程界广泛应用的Wen and Yu式用于计算液-固流态化系统有更高的精确性,最大偏差小于7.63%,均方差为5.27%,而且对球形与非球形颗粒都适用。
