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.

高压均质是一种成熟的工业工艺，用于生产含有亚微米范围内的液滴的技术，但该技术已应用了数十年。过程和中断单元仍然是在反复试验的基础上实现的，原因是由于高速度梯度和波动以及多相的存在，中断单元内的流场非常复杂。按流程这些情况对在线测量技术提出了很高的要求，该研究项目的目的是表征现实条件下高压均质过程中液滴破碎的物理机制。最初，拟议的项目将仅关注单相、牛顿、非空化流体。在进行流动表征后，将使用单个液滴（分散）来研究液滴破碎。相分数<< 1 %），没有表面活性添加剂。然而，空间和时间分辨率限制了现实微尺度上整个过程的表征，因此，在放大的设备（M = 5 和 50）中研究了具体问题。该程序允许验证液滴破碎的可扩展性，对现实的微尺度（M = 1，孔直径 d = 0.2 mm，分别）以及 M = 5 的放大系统进行研究。（d = 1 毫米）将由位于卡尔斯鲁厄的 KIT 进行，将利用多年的乳化技术经验来系统地研究流动条件和液滴破碎，参数包括雷诺数、孔口的几何形状、尺寸、通过利用其在流量测量技术方面的专业知识，慕尼黑大学将重点研究大范围内的选定方面。尺度系统（M = 50，孔口直径 d = 10 mm，分别）。这里，主要强调在选定参数下详细获取液滴破坏机制以及描述液滴的形状和动力学。为根据材料、工艺和几何参数等边界条件预测所得液滴尺寸分布奠定基础。因此，从长远来看，这将有助于有针对性地改进高压破坏过程。关于选择性、产物收率以及能量输入。