To study axial/radial profiles of particle velocity in the affected region of an integrated riser outlet, a cold model was developed for the integrated riser reactor combining the gas-solid distributor with the fluidi...To study axial/radial profiles of particle velocity in the affected region of an integrated riser outlet, a cold model was developed for the integrated riser reactor combining the gas-solid distributor with the fluidized bed. Constraints, related to the gas-solid distributor and the upper fluidized bed, imposed on the particle flow in the riser outlet region, were investigated experimentally. The experimental results showed that with increasing superficial gas velocity, these constraints have strong influences on particle flow behavior, the particle circulation flux in the riser, and the height of the static bed material of the upper fluidized bed. When the constraints have greater prominence, the axial profile of the cross-sectionally averaged particle velocity in the outlet region initially increases and then decreases, the rate of decrease being proportional to the constraint strength. Along the radial direction of the outlet section, the region where the local particle velocity profile tends to decrease appears near the dimensionless radius r/R = 0.30 initially and then, with increasing constraint strength, gradually extends to the whole section from the inner wall. Based on the experimental data, an empirical model describing the constraint strength was established. The average relative error of the model is within 7.69%.展开更多
针对当前资产定位系统定位精度、建设成本和部署灵活性难以有效平衡的问题,基于BLE Mesh采用多维标度分析(MultiDimensional Scaling-Map,MDS-MAP)定位算法设计了一种资产定位系统。系统首先对原始接收信号强度(Received Signal Strengt...针对当前资产定位系统定位精度、建设成本和部署灵活性难以有效平衡的问题,基于BLE Mesh采用多维标度分析(MultiDimensional Scaling-Map,MDS-MAP)定位算法设计了一种资产定位系统。系统首先对原始接收信号强度(Received Signal Strength Indicator,RSSI)进行高斯-卡尔曼融合滤波,提高了RSSI值的准确性;然后利用生存时间(Time To Live,TTL)对中继节点进行约束,提高了数据传输的有效性;最后利用半径弥补法与Bellman-Ford融合迭代方案对生成的距离矩阵进行修正,减小了测距误差。实验结果表明,所设计的系统可有效完成蓝牙标签信息更新以及位置展示,平均定位精度达到了0.94 m。本系统具有成本低、工程实施方便的优点,有一定的应用价值和发展前景。展开更多
基金support from the National Natural Science Foundation of China(Grant nos.21106028 and 20976190)the Hebei Province Natural Science Foundation of China(Grant no.B2013202125)
文摘To study axial/radial profiles of particle velocity in the affected region of an integrated riser outlet, a cold model was developed for the integrated riser reactor combining the gas-solid distributor with the fluidized bed. Constraints, related to the gas-solid distributor and the upper fluidized bed, imposed on the particle flow in the riser outlet region, were investigated experimentally. The experimental results showed that with increasing superficial gas velocity, these constraints have strong influences on particle flow behavior, the particle circulation flux in the riser, and the height of the static bed material of the upper fluidized bed. When the constraints have greater prominence, the axial profile of the cross-sectionally averaged particle velocity in the outlet region initially increases and then decreases, the rate of decrease being proportional to the constraint strength. Along the radial direction of the outlet section, the region where the local particle velocity profile tends to decrease appears near the dimensionless radius r/R = 0.30 initially and then, with increasing constraint strength, gradually extends to the whole section from the inner wall. Based on the experimental data, an empirical model describing the constraint strength was established. The average relative error of the model is within 7.69%.
文摘针对当前资产定位系统定位精度、建设成本和部署灵活性难以有效平衡的问题,基于BLE Mesh采用多维标度分析(MultiDimensional Scaling-Map,MDS-MAP)定位算法设计了一种资产定位系统。系统首先对原始接收信号强度(Received Signal Strength Indicator,RSSI)进行高斯-卡尔曼融合滤波,提高了RSSI值的准确性;然后利用生存时间(Time To Live,TTL)对中继节点进行约束,提高了数据传输的有效性;最后利用半径弥补法与Bellman-Ford融合迭代方案对生成的距离矩阵进行修正,减小了测距误差。实验结果表明,所设计的系统可有效完成蓝牙标签信息更新以及位置展示,平均定位精度达到了0.94 m。本系统具有成本低、工程实施方便的优点,有一定的应用价值和发展前景。
