T型微通道反应器内气液两相流及气液固多相流模拟研究

微通道内流体流动及标量传递信息的获取一直是研究热点之一。基于CFD模拟技术,研究了微通道中气液两相及气液固三相的流动过程。开发了颗粒孔隙尺度网格处理方法,获得了微通道内气液两相流型随气液流速及气相入口尺寸的变化规律,初步分析了催化剂颗粒缝隙气泡的变形、破碎等情况,为微反应器的合理设计提供了指导。     

两种工艺下某天线微通道冷板特性的实验研究

目的研究不同工艺下微通道冷板的特性及成因。方法以实验研究为基础,对两种工艺方式(增材制造和真空钎焊)下的某天线微通道冷板进行流动和传热分析。另外,还使用CT技术对两种冷板的内部结构进行成像。结果获得了冷板特性数据和内部成像图片。结论分析表明,增材制造的微通道冷板具有良好的性能,具备工程应用的潜力。     

格子玻尔兹曼方法(LBM)及其在微通道绕流中的应用

介绍了格子玻尔兹曼方法基本理论与计算方法,并建立了D2Q9计算模型,对宏观尺度及微通道中的非稳态绕流进行了数值模拟,得到了绕流过程的速度分布和涡量分布等信息,对流场结构、固体阻力、尾涡脱落等变化规律进行了分析。结果表明,格子玻尔兹曼方法以其计算稳定、效率高等优势能够应用于微反应器领域的数值模拟;同等液相停留时间条件下,微反应器中的圆柱绕流湍动程度明显降低,未形成周期性涡流,流动更加均匀稳定,有助于实现化学反应的精确控制。     

Online microchannel preconcentrator for carbofuran detection

A simple and rapid online microchannel preconcentrator coupled with an amperometric detection for the analysis of carbofuran using polyethylene glycol coated onto magnetic particle (PEG-magnetic particles) sorbents was developed. This simple-to-prepare microchannel preconcentrator used an external magnet to retain the PEG-magnetic particle sorbents inside the microchannel. Under optimum conditions, the system provided two linear ranges, from 0.01 to 10.0 mg L^?1 and from 10.0 to 130.0 mg L^?1 with a limit of detection of 8.7 ± 0.1 μg L^?1. The microchannel preconcentrator provided very good stability; it can be used for up to 326 consecutive injections of 5.0 mg L^?1 carbofuran with a relative standard deviation of less than 3%. The developed system provided a good microchannel-to-microchannel and a good electrode-to-electrode reproducibility (n = 6, %RSD < 1). It also provided an excellent selectivity when it was tested with two other carbamate pesticides, carbaryl and methomyl, with a 43 and 256 times higher detection sensitivity for carbofuran, respectively. The developed system was successfully applied to detect carbofuran in surface water samples obtained near vegetable plantation areas. The concentrations of carbofuran in these samples were found to be in the range of non-detectable to 0.047 ± 0.001 mg L^?1. The developed system is easy to operate and easy to couple with other analytical instruments and it could be easily adapted for the analysis of other polar organic contaminants.     

氢氧直接合成过氧化氢反应研究进展

重要化工原料过氧化氢的绿色、高效、安全制备工艺一直是研究热点之一。由氢气和氧气直接化合制备过氧化氢法(DSHP)具有过程简单、成本低等优点,受到了广泛关注。本文从原子层面反应机理、催化剂中贵金属的选取和复配效应、载体的组成和空间构型、反应介质的组成以及反应器中的流动控制等5个方面,总结近十年在利用微反应器实现DSHP反应方面的进展,并对该工艺的发展方向做出展望。