Abstract:

In the riser large-scale cold mode experiments, the pressure pulsations in the jet influence zone are collected. To make a comparison, effects of upward and downward jets are investigated. The pressure pulsation distribution and gas-solid interaction pattern in the jet influence zone are obtained. On this basis, the connection between pressure pulsation characteristics and jet velocity in the influence zone is established by using wavelet analysis. The results show that the downward inclined jet makes the overall value of the pressure pulsation standard deviation increase by 30% in the riser comparing with the upward inclined jet. At the same time, by introducing the downward inclined jet, the axial and radial variation gradients are reduced, so that the intensity of gas-solid mixing process increases. In wavelet analysis, as the jet velocity increases, the wavelet energy value at each scale in the region near the nozzle inlet decreases by 25% when the jet inclines upward. While in the downward inclined jet influence zone, the wavelet energy value increases by 29%, of which ED4 and EA8 accounted for the largest energy. Generally, it is found that the downward inclined jet can effectively increase the intensity of high-frequency pressure pulsation in the jet influence zone, which is conducive to improving the gas-solid contact effect.

Key words: riser, jet, jet influence zone, multiphase flow, pressure pulsation, wavelet analysis, distributions

摘要：

在提升管大型冷模实验装置中，采集了两种射流形式（射流向上倾斜和射流向下倾斜）提升管射流影响区内的压力动态数据，获得了压力脉动强度的轴、径向分布，并结合压力脉动信号的小波分解分析了不同射流形式对提升管内气固间作用规律的影响，建立了射流影响区内压力脉动特性与射流速度的联系。结果表明，与向上倾斜射流相比，向下倾斜射流使得提升管内压力脉动标准偏差整体数值增大约30%，而轴向、径向变化梯度均有所减小，气固混合过程的强度增大。小波分析结果表明，随着射流速度的增大，射流向上倾斜时，射流喷嘴入口截面附近区域小波能量整体数值将降低约25%，而在射流向下倾斜的射流影响区内小波能量整体数值将增大29%左右，其中ED4、EA8能量占比最大；向下倾斜的射流能有效增加射流影响区内高频压力脉动强度，有利于提高气固接触效果。

关键词: 提升管, 射流, 射流影响区, 多相流, 压力脉动, 小波分析, 分布