Technical Sprays
Technical sprays are used in various areas of everyday life and technical applications. Examples include surface coating processes in the automotive industry, conversion of chemical energy in internal combustion engines or in rocket engines, efficient thermal management of surfaces to be cooled, applications in medical technology such as spray application of stem cells, spray drying in food or drug production, and particle production by spray flame synthesis.
In this lecture, the technical atomizers required for these industrial applications are presented. Starting from the atomizer as a black box, where a contiguous liquid is converted into a two-phase flow with ligaments and droplets as well as surrounding gas phase, the atomization mechanisms necessary for atomization and spray generation are presented. Since the various technical applications have specific requirements for the spray, very different methods of atomization and spray generation result. Examples are pressure atomization, rotation-induced atomization and also shear-induced atomization. The description of the disintegration and all partial phenomena of these highly complex two-phase flows is the content of this lecture.
The limits of today's experimental and numerical methods to characterize sprays and atomization processes are shown within this lecture on the basis of the current state of research. In the context of the accompanying exercise, there is the possibility to estimate physical quantities of sprays, to get to know measurement methods and to apply them in group work under real conditions.
Content
- relevance of technical sprays and atomization processes for different applications in the fields of mobility, energy supply, industry, medicine.
- atomization mechanisms
- technical atomization
- droplet processes
- spray characteristics
- optical measurement technology for spray characterization