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过程工程学报 ›› 2020, Vol. 20 ›› Issue (7): 798-806.DOI: 10.12034/j.issn.1009-606X.219320

• 流动与传递 • 上一篇    下一篇

喷嘴射流在气固提升管内的扩散和混合行为

闫子涵, 许 峻, 范怡平, 卢春喜*   

  1. 中国石油大学(北京)重质油国家重点实验室,北京 102249
  • 收稿日期:2019-10-17 修回日期:2019-12-03 出版日期:2020-07-22 发布日期:2020-07-21
  • 通讯作者: 闫子涵
  • 基金资助:
    博士后创新人才支持计划;中国石油大学(北京)科研基金资助

Diffusion and mixing behaviors of nozzle jet in the gas-solid riser

Zihan YAN, Jun XU, Yiping FAN, Chunxi LU*   

  1. State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China
  • Received:2019-10-17 Revised:2019-12-03 Online:2020-07-22 Published:2020-07-21
  • Contact: Zi-Han YAN

摘要: 为获得不同形式射流在提升管内的扩散特征和气固混合行为,利用气体示踪技术,在大型提升管冷模实验装置中考察向上和向下倾斜两种射流的影响。通过引入射流特征浓度获得射流相在提升管内的分布特征,通过计算停留时间方差获得提升管内射流的局部停留时间分布特征,根据停留时间方差与操作条件及轴向高度的拟合结果计算射流影响区高度。结果表明,斜向下的射流进入提升管后沿径向分布更均匀,且可使混合流体在较短的距离内实现由近似“全混流”到近似“平推流”的过渡,与斜向上的射流相比,向下倾斜的射流可缩短射流混合区高度约50%。

关键词: 提升管, 射流, 停留时间

Abstract: The gas tracer technology was employed in this research to investigate the jet diffusion and its mixing with particles in the gas?solid riser. Studies were finished in a large scale cold model riser. In order to investigate the influence of different types of jets, both upward and downward injections were used during experiments. By introducing the jet characteristic concentration, the radial distributions of jet after injecting into the riser were obtained. Results showed that the distribution of jet concentration was more uniform for the case of downward injection. By detecting the tracer gas at various axial and radial points, the local residence time distributions of feed jet were obtained. On this basis, the dimensionless variance was calculated and comparison between upward and downward injections was made. It showed that the values of variance and their fluctuations were large at most axial cross sections when the jet was upward, indicating some serious local backing-mixing of feed jet. If the direction of injection changed to downward, the calculated value of variance was large under the feed nozzles, while the value of variance was small and its radial distribution was uniform at the locations above nozzles. This result meant that the jet-solid mixing flow can change into the likely plug flow from a likely full mixed flow easily and quickly under the influence of downward injection. Based on experimental results, the residence time variance was fitted with operating conditions and axial height. Empirical formulas for the cases of both upward and downward injections were obtained. Finally, comparing fitted results with the variance value in the riser full mixing zone, the influence height of jet in the riser was calculated. Results showed that the influence height of feed jet can be shortened by 50% if the downward injection was chosen.

Key words: Riser, Jet, Residence time