Investigations regarding the measurement of relevant flow conditions for droplet deformation and disruption in high pressure homogenization with orifices and scalability of mechanisms

关于测量带有孔口的高压均质化中液滴变形和破裂的相关流动条件以及机制的可扩展性的研究

基本信息

批准号：
265685259
负责人：
Professorin Dr.-Ing. Heike Karbstein
金额：
--
依托单位：
Bereich I: Lebensmittelverfahrenstechnik
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2015
资助国家：
德国
起止时间：
2014-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/265685259?language=en
关键词：
Investigations regarding measurement relevant flow

项目摘要

High pressure homogenization is a well established industrial process for the production of emulsions containing droplets within a submicron range. This technology has been applied for many decades. However, mechanisms leading to droplet breakup are still not completely understood. As a consequence, the optimization of process and disruption units is still realized on a trial and error basis. Reasons for this are the complex flow field inside a disruption unit due to high velocity gradients and fluctuations as well as the presence of multiple phases. Additionally, access to small geometries is limited by process conditions such as high pressures. These cirsumstances set high demands on inline measurement techniques. The aim of this research project is to characterize flow conditions and physical mechanisms of droplet breakup during high pressure homogenization under realistic conditions. Applying the optical measurement technique µPIV allows the realization of this objective with high pre-cision. Initially, the proposed project will focus only on single-phase, Newtonian, non-cavitating fluids. After flow characterization, droplet breakup will be investigated using single droplets (dispersed phase fraction << 1 %) without surface-active additives. However, spatial and temporal resolution limit the characterization of the complete process on a realistic microscale. Therefore, specific questions are investigated in scaled up devices (M = 5 und 50). This procedure allows verifying the scalability of droplet breakup. The investigations on a realistic microscale (M = 1, orifice diameter d = 0.2 mm, resp.) as well as a scaled up system of M = 5 (d = 1 mm) will be conducted by the KIT in Karlsruhe. Years of experience in emulsification technology will be used to systematically study flow conditions and droplet breakup. Parameters that will be varied are the Reynolds number, geometry of the orifice, size, and starting position of the droplets. Material parameters such as viscosity of each phase and surface tension will be changed likewise. By utilizing their knowhow in flow measurement techniques, the UniBw in Munich will focus on investigating selected aspects within a large scale system (M = 50, orifice diameter d = 10 mm, resp.). Here, the main emphasis lies on a detailed acquisition of droplet disruption mechanisms at selected parameters as well as describing the droplets' shape and dynamics. This research project will build the foundation to predict resulting droplet size distributions from boundary conditions like material, process and geometrical parameters. Therefore, a function describing the disruption of droplets will be developed. In the long term, this will help to improve high pressure homogenization processes in a targeted way regarding selectivity, product yield as well as energy input.

高压均质化是一种良好的工业过程，用于生产含量范围内的液滴的乳液。该技术已应用了数十年。但是，导致液滴分解的机制仍然尚不完全了解。结果，过程和中断单元的优化仍在试用和错误基础上实现。原因是由于高速度梯度和波动以及多个阶段的存在而导致破坏单元内部的复杂流场。此外，对小几何形状的访问受过程条件（例如高压）的限制。这些公民对内联测量技术提出了很高的要求。该研究项目的目的是表征在现实条件下高压均质化期间液滴破裂的流动条件和物理机制。应用光学测量技术µPIV可以通过高率来实现此目标。最初，拟议的项目仅专注于单相，牛顿，非散热流体。流动表征后，将使用单滴（分散相位分数<< 1％）研究液滴分解，而无需表面活性添加剂。但是，空间和临时分辨率限制了在逼真的微观上的整个过程的表征。因此，在规模的设备中研究了具体问题（M = 5和50）。此过程允许验证液滴分解的可扩展性。对逼真的显微镜的研究（M = 1，孔口直径d = 0.2 mm，rups。）以及M = 5（d = 1 mm）的缩放系统将由KARLSRUHE中的Kit进行。多年的乳化技术经验将用于系统地研究流动条件和液滴破裂。将会有所不同的参数是雷诺数，孔口的几何形状，大小和液滴的起始位置。材料参数（例如每个阶段的粘度和表面张力）也将同样更改。通过在流量测量技术中利用其知识，慕尼黑的UNIBW将集中于研究大型系统内选定的方面（M = 50，孔口直径d = 10 mm，分别）。在这里，主要重点在于在选定参数上对液滴破坏机制的详细获取以及描述液滴的形状和动力学。该研究项目将建立基础，以预测从材料，过程和几何参数等边界条件等边界条件中产生的液滴尺寸分布。因此，将开发描述液滴破坏的函数。从长远来看，这将有助于在选择性，产品产量和能量输入方面以目标方式改善高压均质化过程。