Andreas Kilzer

Virtual Labs and Remote Labs: Practical experience for everyone

Laboratory experiences should be available for a great number of students in engineering education, especially at times when the number of students is even more increasing. Virtual Labs and Remote Labs are innovative tools used for improvement. They are either simulating experiments (Virtual Labs) or remotely operated plants (Remote Labs). At Ruhr-University Bochum, the implementation of eight new labs was supported by the project ELLI (excellent teaching and learning in engineering sciences). Didactical concepts as well as sustainable implementations were among the criteria of the independent jurys decision. After their setup, the management of the variety of labs is the next step. This short paper reports the work in progress in the year 2013, the whole process is to be continued and improved.

Particle Formation from Gas-Enriched Polymeric Melts and Polymeric Solutions

Within the scope of this subproject, a gas-assisted high-pressure spray process (PGSS—Particles from Gas-Saturated Solutions) was investigated. The gas used for the atomization is carbon dioxide (CO2) which for the most purposes is in supercritical state. In the spray process, the gas is partly dissolved into the liquid before the atomization. The dissolved CO2 changes the physical properties of the liquid such as viscosity and surface tension and enables high-viscous substances to be atomized. Several authors were able to atomize high-viscous substances such as polymers, fats, and waxes with such a spray process. Nevertheless, till now the fundamental influence of the CO2 on the atomization phenomena has not been taken into account. For this reason, experiments which shall clarify how the CO2 affects the spray and particle formation have been carried out systematically within this project. Sprays of water, polymers, and aqueous polymeric solutions were observed and investigated. The liquids were sprayed as pure substances as well as CO2-enriched substances from an autoclave in a batch wise working process. To get a deeper understanding of the observed effects, optically transparent spray geometries were developed. Observations of the flow regime of the gas-enriched liquids gave explanations of the governing atomization phenomena. The results of the experiments show that the working principle of the PGSS process is based on the phenomena of flash atomization. Classical phenomena such as jet and lamella breakup can be neglected for the continuously working process. In further experiments, powders of polyethyleneglycols (PEG 6000) were generated using the continuously working process. Several spray devices were used such as hollow cone nozzles, capillaries, and orifices. The results show that powders with average particle size distributions in the order of 100 μm can be generated independently from the design of the spray device. Therefore, it is proven, that the flash atomization is the governing working principle in the PGSS process.

Pulverisation of Emulsions with Supercritical CO2

With the use of a carbon dioxide-assisted high pressure spraying process, it is possible to manufacture solid emulsions with or without the employment of surfactants. Depending on the process parameters, such as spray pressure, temperature, and gas-to-liquid ratio, various powder morphologies and sizes in the range of micrometers can be obtained. The aim of the project is to investigate and compare the fundamental differences in the spray formation mechanisms of this process to the conventional ones. To this end, firstly various high pressure thermo- and fluid dynamic data have been investigated to define the process and identify different effects coming from the liquid’s properties. Two model emulsions, water, and tristearin (water in oil) and rapeseed oil and polyethylene glycol (oil in water) have been chosen. Using a pseudo shadowgraphy technique spraying experiments with pure and gas-saturated liquids as well as the emulsions have been carried out with a flat fan orifice. The images of the sprays illustrate that the carbon dioxide generally leads to an earlier sheet breakup by gas nucleation. An increase in saturation pressure led to atomisation directly after the nozzle for rapeseed oil and tristearin. A decrease in breakup length of the liquid sheet was also observed for the water in oil emulsion. Solid emulsion particles were also produced in the range of 10 μm with various concentrations of the dispersed phase. It was shown that these can be produced without the use of an emulsifier. Moreover through the employment of an optical chamber, the encapsulation efficiency of the process was linked to the quality of the emulsion, that is size of dispersed droplets.

ALLES ING! Count me in! Attracting human talents in providing open access to universities with focusing on individual opportunities in engineering sciences

In higher engineering education of the 21st century, it is necessary to “go with the times” and make use of many and varied ways when it comes to attracting young talents for technical studies. At the Ruhr Universität Bochum, the Project ELLI decides to start an offensive with the engineering faculties: They give an insight into “Who we are and what we are doing” in the framework of their new, joint initiative “ALLES ING!”. In this endeavor, the faculties for Civil and Environmental Engineering, Mechanical Engineering and Electrical Engineering and Information Technology present themselves with a shared “business card” to the public beyond, as well as within the university. This paper documents the concept and development of “ALLES ING!” as a means of attracting human talent for engineering education, as well as the challenges and opportunities that still lie ahead.