Study on mixing characteristics in bottom-blowing stirred reactor using image analysis

doi:10.16085/j.issn.1000-6613.2017-0071

Abstract

Abstract: The oxygen-enriched bottom-blowing smelting process is taken as research object. In order to measure and compare the local mixing characteristics in the bottom-blowing stirred reactor,the grayscale intensity was obtained based on field images of bubble perturbation. According to the actual size of bottom-blowing copper melting furnace,the test platform for water model of gas blowing was built. By watching high-speed videos of experimental process at different design parameters,the field RGB images of water model above the nozzles were captured and saved. Only the area undisturbed by apparatus was extracted as the study area. Finally,the grayscale intensity average and standard deviation of green component can be obtained. It was found that the green component of bubble RGB images extracted the contour features of actual bubble images more than other grayed images at our experimental conditions. The horizontal profiles of green component present obvious single apex and double peak,corresponding to the operating conditions of single-line nozzle and double-line nozzles,respectively. These results proved the validity of grayscale intensity for characterizing the mixing process. The mean and standard deviation time series of grayscale intensity in study area were calculated. Results showed that most times series follow Gaussian distributions statistically at the dynamic equilibrium stage of the bath. This work provides some academic bases and references on pushing the research about adopting image analysis techniques to investigate flow and mixing in the bottom-blowing stirred reactors.

Key words: gas-liquid flow, distributions, stirred vessel, mixing, imaging

摘要： 以富氧底吹熔池熔炼过程为研究对象，基于气泡扰动形成流场图像测算灰度级强度，测算与比较底吹搅拌反应器内的局部混合特性。参照某企业底吹炼铜炉实际尺寸，搭建气体喷吹水模型试验平台；利用高速摄像机拍摄不同设计参数下的试验过程，捕获并存储水模型中喷口上方流场的彩色图像；截取未受装置干扰的研究区域，测算其绿色成分的灰度级强度均值与标准差。研究发现：气泡扰动流场RGB图像的绿色成分在本试验条件下对于真实图像气泡轮廓特征提取更为准确；绿色成分图像的水平剖线针对单排喷口与双排喷口分别呈现单峰与双峰，验证了以灰度级强度表征混合特性的准确性；测算研究区域的灰度级强度均值时间序列和标准差时间序列，最终发现：在熔池动态平衡阶段，大部分时间序列在统计学意义上服从正态分布。本研究为推进图像分析技术在底吹搅拌反应器流动与混合特性研究方面提供了参考依据。

关键词: 气液两相流, 分布, 搅拌容器, 混合, 成像

CLC Number:

TF811

XIAO Qingtai, WANG Shibo, LI Peng, GAO Qin, XU Jianxin, WANG Hua. Study on mixing characteristics in bottom-blowing stirred reactor using image analysis[J]. Chemical Industry and Engineering Progress, 2017, 36(09): 3195-3202.

肖清泰, 王仕博, 李鹏, 高勤, 徐建新, 王华. 基于图像分析的底吹搅拌反应器混合特性[J]. 化工进展, 2017, 36(09): 3195-3202.

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