RESS 过程中高频脉动力场及对微粒合成与包覆的作用机制

研究超临界流体快速膨胀过程中高频脉动波的产生和传播机制及其特征参数表征。研究超临界流体膨胀射流中高频脉动波所产生的高频脉动力场结构及对射流中微粒成核、晶粒生长及纳米膜包覆的作用机制和控制方法。对揭示超临界流体快速膨胀过程的本质规律起关键作用，在超细微粒制备与纳米膜包覆用于缓释、改性、单分散等方面的独到应用具有重要意义。

The experimental system for investigating supercritical fluid technology including the measurement of turbulent field in RESS process is built. A sensor with high sensitivity for dynamic pressure is adopted to measure the turbulence signals in the rapid expansion of supercritical fluid solution (RESS) process. Experimental results show that there exists a quasi-periodical coherent structure in a jetting flow. The forming mechanism, characteristics of the coherent structures and its change with the parameters are investigated. It opens a new way to explain the inconsistent result about the influence of parameters on the size of the particles prepared in RESS process. The particle coating for release control of a key component in particles is investigated by introducing the RESS process into a fluidized bed. Supercritical carbon dioxide is employed as an environmental benign solvent to achieve the organic modification of fine particles with a molecular layer. The surface properties are modified efficiently. Inorganic coating with a nano-film on particle surface is also investigated. The chemical bonding and the film formation processes on the particle surface are studied. The optimal conditions of the continuous and uniform coating with nano-film are obtained. The function and dispersion of the fine particles are improved.