CT在气固两相流研究中的应用
文献类型：学位论文
| 作者 | 孟凡勇 |
| 学位类别 | 博士 |
| 答辩日期 | 2009-09-28 |
| 授予单位 | 中国科学院过程工程研究所 |
| 授予地点 | 过程工程研究所 |
| 导师 | 李静海 |
| 关键词 | 气固两相流 CT 团聚物 虚拟研究 GPU集群 CUDA CFB |
| 其他题名 | Application of CT to Gas-Solid Two-Phase Flow |
| 学位专业 | 化学工程 |
| 中文摘要 | 气固两相流广泛存在于过程工业中，流动结构的变化对其行为有着重要的影响。CT（Computed Tomography，计算机层析成像）作为一种无损断层测量手段，对于研究两相流动态结构有重要意义，从而引起了两相流研究领域的极大兴趣。本文对CT这项非插入、无干扰的测量手段进行了系统的研究，对其应用于两相流研究中遇到的数据截断、投影中心校正、射线硬化、CT标定、运动伪影、探测器异常等一系列问题给出了相应的解决方案，并使用定制开发的第三代等距扇束CT（IPE-CT）在ETH-IPE CFB半工业反应器上进行了实验验证，为CT应用于两相流动态结构测量提供了坚实基础。 由于气固两相流系统的内在复杂性，CT对此类系统测量时，无法产生精确可重复的流场供实验参数优化，本文针对这一难题，将计算流体力学（Computational Fluid Dynamics，CFD）的三维计算与CT扫描模拟相结合，提出了虚拟研究的方法：以ETH-IPE CFB的全尺寸三维模拟结果做为CT模拟扫描的对象，模拟IPE-CT的测量过程，对计算得到的流场进行断层扫描，从而使得CT应用于气固两相流研究时定量的实验参数优化成为可能。本文使用此方法对滤片法降低射线硬化进行了定量的研究，确定了适用于ETH-IPE CFB 反应器的滤片参数；采用虚拟研究的方法，本文还对不同的CT标定方法进行了定量的比较研究。 团聚物是气固两相流研究的一个热点，它的生灭演化对系统的性能产生着重要影响。本文提出了一种基于X射线的近壁处团聚物测量方法，该方法可非插入无干扰的对团聚物的空隙率、尺寸、速度、加速度等性质进行同时测量，为深入理解团聚物这种介尺度结构提供了新的测量手段。 为实现高速CT在线监测两相流这一目标，本文对断层图像重建的软、硬件加速进行了研究，并采用CUDA、MPI与OpenGL混合编程，首次实现了基于GPU集群的断层图像重建加速，达到了准实时的图像重建。 |
| 英文摘要 | The gas-solid two-phase flow exists widely in process industries, and the variation of flow structures has great effects on its behaviour. Computed tomography (CT), as a non-destructive measurement technique, has aroused great interests in the multiphase research field. In this thesis, a systematic study was performed for the application of CT to gas-solid two-phase flow. Several problems, such as truncation, beam hardening, calibration, motion artifact and detector malfunctioning, which were encounted while introducing CT into the multiphase research, were tackled with solution schemes and further validated using the in-house-developed IPE-CT on the semi-industrial scale reactor, namely ETH-IPE CFB. Due to the inherent complexity in gas-solid two-phase flow, it is almost impossible to provide a precisely repeatable flow field for the calibration and optimization of CT. In order to settle this problem, a virtual experimentation technique combining computational fluid dynamics (CFD) and CT simulation was presented. Taking ETH-IPE CFB as the prototype, a 3D full-sized computatioin was performed and thereby generated flow field was used as the scanning phantom for CT simulation. By this means, the quantitative study of beam hardening correction, CT calibration and parameter optimization was realized. Cluster is one of critical issues in the gas-solid two-phase flow. Its formation, dissolution and evolution have significant effects on the two-phase flow behaviour. An X-ray based technique for the measurement of clusters in the near wall region was proposed in this study. By analyzing the one dimensional projection data, the information of voidage, size, velocity and acceleration of the cluster can be obtained simultaneously. To realize the on-line monitering of CFB reactor, the speed-up of reconstruction, via both software and hardware means, was studied in the last part of this thesis. Quasi-real time reconstruction based on a GPU cluster was realized, which makes possible for the on-line monitoring of reactor by high-speed CT. |
| 语种 | 中文 |
| 公开日期 | 2013-09-13 |
| 页码 | 280 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1095]  |
| 专题 | 过程工程研究所_研究所（批量导入） |
| 推荐引用方式 GB/T 7714 | 孟凡勇. CT在气固两相流研究中的应用[D]. 过程工程研究所. 中国科学院过程工程研究所. 2009. |
入库方式： OAI收割
来源：过程工程研究所
浏览0
下载0
收藏0
其他版本
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。