振荡流反应器注入分散特性的实验研究

【作者】 李安实；

【导师】 吴嘉；

【作者基本信息】 浙江大学 ， 化学工程， 2002， 硕士

【摘要】 本论文建立了振荡流场混合器(OFM)实验装置，并对OFM内的注入分散过程进行了研究。实验采用了染料作为示踪剂的流动显形技术，利用摄像机拍连续拍摄整个注入分散过程，然后使用计算机图像处理技术获得注入分散特性的定量描述。 文中首次提出用流场图象的象素点灰度值的方差和来表征浓度场的非均匀度，用该方差和随时间衰减的变化规律来表征流场的注入分散特性。本文主要对振荡雷诺数(Re_o)和斯特劳准数(St)对振荡流场中注入分散特性的影响做了比较深入的研究，并对净流雷诺数(Re_o)的影响做了初步的探讨。 通过观察实验现象与分析实验数据，我们发现振荡特性参数Re_o和St对注入分散特性的影响显著，当St较小时，非均匀度(方差和)随时间呈指数性衰减，衰减速率随Re_o增大而增大：St较大时，分散效果不良，在大Re_o值下仍不能良好分散。在振荡强度不是很大的情况下，净流量的引入对腔室内整体涡流的影响较大，St较大时，这种变化尤其明显。当Re_o＞＞Re_n时，振荡流场的注入分散特性随Re_n变化很小。 实验研究证明：OFM能够实现高效注入分散过程并且容易控制注入分散过程的时间特性，可以适应不同反应过程对注入区浓度场的要求。更多还原

【Abstract】 In this work an experimental setup of oscillatory flow mixer (OFM) was built up and the study on the injection dispersion in OFM was carried out.In the experiment, the flow visualization technique was used with a solution of blue dye as the tracer, the injection dispersion process was monitored with a digital video camera, and the recorded image was treated with computer image processing technique to obtain the quantitative description of injection dispersion performance.It is first time that the variance sum of gray scale values of pixels was used to characterize the inhomogeneous degree of concentration fields and that the attenuation rate was used to characterize the injection dispersion performance of flow field. The work focused on the influence of oscillatory Reynolds number(Re0) and Strouhal number(St) to the injection dispersion performance of OFM, and the effect of net flow Reynolds number(Ren) was explored preliminarily.The observation of experimental phenomena and analysis of experimental data showed that the oscillatory parameters Re0 and St have a strong influence to the injection dispersion performance of OFM. At small St, the inhomogeneous degree(the variance sum) attenuates exponentially with time increasing, and the rate of attenuation increases with Re0. At large St, the dispersion is poor even at very large Re0. Ren takes effect only at large St and small Re0. As Re0籖en. the changes little with Ren.The experimental study suggests that OFM should provide high-efficient injection dispersion performance and good controllability on the time character of dispersion process, and is able to satisfy the requirement of various reaction processes to the concentration distribution in the injection area.更多还原