基于PIV技术高固厌氧消化气-液-固三相复杂流场可视化及流动控制机理研究

High solid anaerobic digestion (HSAD) had the advantages of small reactor, low heating energy and less digestate. However, its digestate was of high viscosity and poor flow property. Besides, huge dead zones existed in HSAD system and lead to HSAD’s poor performance. In the available literature, the visualization of anaerobic digestion still remained in the simulation via computer flow dynamics (CFD), which was complex, time costing and with limited precision. The flow control mechanism of HSAD still remained as a “black box”, available study usually focused on the effect of mixing on anaerobic digestion, the relationship between HSAD’s flow field and performance was not yet found. This study will investigate the visualization of HSAD which is “simple, fast, high precision” via particle image velocimetry. Besides, the reactor, impeller and rotating speed’s effects on HSAD’s flow field will also be revealed. The optimal flow field of HSAD will also be studied. Furthermore, this study will throw new insight into the flow control mechanism of HSAD. This application would help modify the HSAD’s reactor and benefit its control.

高含固率厌氧消化（简称高固厌氧消化）具有反应器体积小、运行能耗低、沼渣少的优点，但其物料粘度大、流动性能差，系统内存在大量死区，导致高固厌氧消化运行效果不理想。目前文献中，厌氧消化流场的可视化大多停留在计算流体动力学模拟的程度上，其计算过程复杂、耗时长、精度有限。此外，高固厌氧消化的流动控制机理尚处于黑箱状态，即研究重点为搅拌条件对厌氧消化运行效果的影响，未发现流场与高固厌氧消化运行效果及稳定性关系的相关研究。本研究拟基于粒子图像测序技术探索一种“简便、快速、高精度”高固厌氧消化气-液-固三相复杂流场的可视化，揭示高固厌氧消化流场对反应器构型、搅拌设备、搅拌速度等影响因素的响应机理，研究高固厌氧消化流场和运行效果及稳定性的关系，识别适合高固厌氧消化的流场，并揭示高固厌氧消化的流动控制机理。本申请的实施能够为多相高固厌氧消化反应器的优化以及运行调控打下基础。

针对高固厌氧消化物料粘度大、流动性能差，系统内存在大量死区，导致高固厌氧消化运行效果不理想等问题，本项目研究主要内容及成果如下：.（1）基于PIV技术构建了高固厌氧消化气-液-固三相复杂流场的可视化技术，揭示高固厌氧消化流场的流场特征，进而阐明了流场对高固厌氧消化运行效果、运行稳定性的作用规律。.（2）揭示了搅拌器构型、搅拌速度以及反应器构型对高固厌氧消化流场的作用机制，确定了最优高固厌氧消化系统，对不同因素对高固厌氧消化流场的控制机制的内在作用机理进行探索。.本项目的实施有助于调控并优化高固厌氧消化系统的水力学条件，为多相高固厌氧消化反应器的优化以及运行调控打下基础。