Abstract:

A new method was proposed in a cold riser experimental apparatus with height of about 18 m and inner diameter of 100 mm according to the result measured by PV-6D optical fiber to calculate the local particle flux and velocity based on all the sampling time. The new method was compared with the method used in the referring paper. The results showed that the values of local particle flux and velocity calculated by the two methods had a great discrepancy. The maximum, minimum and mean relative errors between the cross-sectional mean particle flux and the measured value calculated by this paper and the referring paper were 606.9%, 241.3%; 221.4%, 89.5% and 388.9%, 145.6%, respectively. Thus, the value of particle flux measured by this paper was relatively low. The cross-sectional mean particle velocity calculated by the referring paper was higher than the operating gas velocity, and the gas-solid slip velocity and slip coefficient respectively varied from -1.6 to -4.7 m·s^-1 and 0.56 to 0.90, respectively, and thus there was a great difference to the actual gas-solid flow in riser. The cross-sectional mean particle velocity calculated by this paper was lower than the operating gas velocity. The gas-solid slip velocity and slip coefficient varied from 0.6 to 9.6 m·s^-1 and 1.11 to 2.14, respectively. There were some problems when using the reflecting optical fiber to measure the particle concentration and it was the main reason that resulted in the higher particle flux, slip velocity and slip coefficient measured by this paper. Furthermore, two fitting functions were come up with to calculate the particle circulation in the riser according to the measuring result by the optical fiber, substituting for the recent volumetric method.

Key words: riser, particle flux, particle velocity, optical fiber probe, volumetric method

摘要：

在一套高约18 m、内径φ100 mm的提升管冷态实验装置上，根据PV-6D光纤探头的测量结果，提出了一种基于整个采样时间计算提升管颗粒局部流率和速度的改进方法，并与文献方法进行了对比。结果表明，两种方法计算的颗粒局部流率和速度相差较大，本文和文献两种方法计算的截面平均颗粒流率与实测值间的最大、最小和平均相对偏差分别为606.9%、241.3%，221.4%、89.5%和388.9%、145.6%，本文方法测量的颗粒流率偏差相对较小。文献方法计算的截面平均颗粒速度均大于操作气速，其气固间滑落速度和滑落系数分别在-1.6～-4.7 m·s^-1及0.56～0.90间变化，与提升管内的气固实际流动存在很大差别；本方法计算的截面平均颗粒速度均小于操作气速，其气固间滑落速度和滑落系数分别在0.6～9.6 m·s^-1及1.11～2.14间变化。反射型光纤探头在测量颗粒浓度时存在的一些问题是导致本文方法测量的颗粒流率、滑落速度和滑落系数偏大的主要原因。此外，根据光纤测量结果，提出了两个计算提升管颗粒循环强度的关系式，可以替代现有的容积法测量。

关键词: 提升管, 颗粒流率, 颗粒速度, 光纤探头, 容积法