In many technical applications, falling film is used. These are thin liquid films that flow along a wall. Such films can be heated either over the wall or the gas phase. In the industry, bitumen films are mainly used in process engineering (eg falling film evaporators) and energy technology (eg in marine thermal power plants). The focus of research today is the hydrodynamics and the intensification of heat transfer to the falling film.
Basically, there are currently three ways to improve the heat transfer from the wall to the film.
One method is the realization of very thin films. A disadvantage of this method, however, is that thin films tend to be unstable.
Another method is the structuring of the wall surface. It has been found that a film which flows over a structured surface has a larger residual area compared to an unstructured surface. Ansys training center in Coimbatore will train you with fluid dynamics and heat transfer.
Furthermore, an electric field can also improve the heat transfer in falling films. If a thin film is under the influence of such a field, the fluid dynamics are influenced by it.
In particular, the local film thickness changes. This change is due to an electrical bulk force and additional pressure on the film surface.
One benefit of such a technology would be the ability to build more compact heat exchangers.
To study the influence of electric fields on hydrodynamics, information about the local film thickness and its temporal change is necessary.
For this purpose, the method of chromatic confocal distance measurement (CCI) is increasingly used. This method uses the dispersion of light to measure distances with high accuracy. The Department of Heat and Mass Transfer (WSA) of the RWTH Aachen now wants to investigate the film thickness under the influence of an electric field using this technique.
The aim of this work is the extension of an existing system so that the falling film can be exposed to an electric field and the film thickness can be determined experimentally using the CCI technique.
For thermo-fluid dynamics in high-pressure gas quenching
High-pressure gas quenching is an established method for the industrial heat treatment of metallic components. The intensity and homogeneity of the quench depend directly on the local flow conditions in the quench chamber and within the batch setup.
The aim of this work is the analysis of the high-pressure gas quenching process for the identification of potentials for increasing the homogeneity and intensity.
For this purpose, the flow conditions within a gas quenching system are measured by means of different experimental methods and quenching experiments with different batch configurations and operating conditions for the determination of the quenching intensity are carried out.
Extensive numerical flow simulations are used to determine the distribution of the quench medium within the quench chamber and the quench intensity within the batch under different boundary conditions.
Based on this, process characteristics are derived which allow adjustment of quench homogeneity and intensity.
Finally, a method for process intensification by means of targeted flow guidance based on nozzle systems will be presented and discussed in comparison with standard setups.
The work shows the potentials for increasing the energy efficiency of plants and processes of high-pressure gas quenching.
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