In this study transport and deposition of submicron particles in turbulent and laminar flows is investigated theoretically. Beginning with the modelling of transport processes in pipe flows, transport onto surfaces and in industrial gas cleaning systems has been calculated. Deposition of particles takes place due to convective diffusion, sedimentation,thermophoresis and impaction. Although different geometries have been investigated a characteristical deposition behaviour has been found with a deposition minimum for submicron particles with diameters larger than 0.1 mm. Transport of these particles often depends on thermo- or electrophoresis.

The detailed investigations of solubility of limestone und gypsum are essential for optimization of process conditions and operating material consumption in the flue gas scrubbers. This study compares thermodynamic predictions based on the Pitzer model for electrolyte activities with experimental data obtained from salt (gypsum, limestone, calcium adipat) solubility tests in aqueous model systems at high ionic strengths under different partial pressures of carbon dioxide. The high ionic strengths in these aqueous suspensions were achieved by addition of calcium chloride, calcium formate und calcium acetate. By means of measured data the Pitzer interaction parameters for ionic pairs Ca2+/HCO3-, Ca2+/SO42-, Ca2+/HCOO-, Ca2+/CH3COO- and Ca2+/(CH4)2(COO)22- at ionic strength up to 8 mol∙kg-1 were fitted and verified. The Pitzer parameters for interaction between calcium ions and carboxylic acid ions were published in this work for the first time. Also for the first time, the values of standard free energies of formation of calcium formate, calcium acetate and calcium adipate are published. The new model parameters allow a better calculation of thermodynamic equilibriums at industrial processes of flue gas cleaning.

In order to describe the alteration of the ships motion with decreasing water depth different approaches were investigated. Within the simulation the best results can be achieved using the "formulation of a dependency of each coefficient of the mathematical model from the water depth". The motions calculated with this method are very close to those simulated with a set of coefficients derived for a single water depth. The formulation of an exponential equation build up of a constant term and a term describing the dependency from the water depth. The application of the exponential function is demonstrated using sets of coefficients from former manoeuvring investigations and it is tested by simulations with the different mathematical models. In this work a simple and in easy usable approach for the consideration of the water depth in the manoeuvring simulation is presented.

The averaged conservation laws are numerically solved for unsteady turbulent flows of compressible fluids using implicit iterative schemes. To investigate the effects of upstream vortices on the flow filed in the stator blade passages of an axial compressor, upstream vortices are modeled by a vortex shedding flow behind a circular cylinder, which moves in the transverse direction at the entrance of the stator blade row. The interface problem arising due to the relative motion of two different reference systems is handled by a novel technique, which allows the evaluation of the numerical flux at the interface also in the same way as at interior points. To validate the interface technique and to exhibit the temporal behaviour of vortices in the blade passages, some results are presented.

This thesis reports on the study of elementary reactions of the carbon radicals C, C2 and C3 at combustion temperatures. The shockwave technologie was used to generate the necessary gas temperatures of 2500 K up to 5000 K. Fast optical measurement techniques were applied for the time resolved observation of radical reactions. For the detection of C2-radicals, a highly sensitive diagnostic was developed, based on a ring-dye-laser spectrograph. The radicals C3 and CN and the atomic species C, N, and O were measured with a CCD-Camera spectrograph and with the atomic-resonance-absorption spectroscopy. The thermal decomposition (pyrolysis) of acetylene (C2H2) was used as a source for Carbon radicals. Results of this thesis are an extension and a verification of reaction mechanisms for the pyrolysis of acetylene as well as the determination of rate coefficients for the decompostion reactions of C2H2, C2H and C2 and for the bimolecular reactions of C2 with H2, O, O2, N2 and NO.

Arising from the discussion about a sustainable development of the energy sector, more and more interest of different industrial branches (e.g. in the automotive field or by the energy supply companies) is actually directed to the use of fuel cells. They show high degrees of ef-ficiency, little pollution and the ability of combined heat and power generation, and moreover they are modularly built. As a fuel they need hydrogen, but the infrastructure of its supply is much worse than necessary. So, at least for a time of transition, hydrogen must be produced from hydrocarbon fuels. A new idea is the hydrogen production from liquid higher hydrocar-bon compositions, as diesel fuel, in a catalytic cracker. This diesel processor is based on a technology developed by the University of Essen-Duisburg at Duisburg. Liquid higher hydrocarbons, as diesel, also contain different sulfur compounds. The aim of this work was to gain knowledge about the influence of sulfur to a complete catalytic cracker system. The study consists of two parts, the first dealing with the influence of sulfur com-pounds to the catalytic cracker itself, and the second with the influence of the products of the reaction of sulfur compounds flowing with the resultant gas into the low-temperature Polymer Electrolyte Membrane Fuel Cell, PEMFC. In the catalytic cracker the influence of sulfur on the activity and the hydrogen selectivity of catalysts of two different precious metals used separately as well as in mixture is investi-gated. Furthermore, the catalysts stability under the cracking temperature of nearly 1,200 K is tested. As an example, the effect of sulfur-containing fuel to a PEMFC is shown and analysed. Moreover, a mathematical-physical model is developed, describing the effects of the degra-dation of a PEMFC by sulfur contamination. Finally, the efficiency of a desulfurizing unit, pre-connected to the fuel cell to extend its lifetime, is investigated.

Modern cranes built for the handling of containers should work efficiently concerning the energy consumption, and should also decrease the time of the handling process by using high trolley velocities. On the other hand these cranes should be able to reach the target positions precisely and without residual vibrations. Especially, the trolley accelerations needed to shorten the operating cycles excite the load as well as the crane structure, leading to vibrations, which should be reduced by suitable control methods. This Dissertation develops energy and time optimal control methods on the basis of suitable models of container handling systems for transferring a load unit. Based on the Pontryagin maximum principle the optimal control methods are determined. Their disadvantage, however, is that they react very sensitively on the inaccuracies of the system parameters. Especially, the data of the containers is very often not known exactly. That is why the input shaping method is taken as an alternative to the optimal solution based on the maximum principle. The corresponding suboptimal solutions are very robust concerning the inaccuracies of the system parameters and the initial conditions. The mechanical modelling takes into account the pendulum like motion of the load as well as the vibration of the crane structure.

This work analyses the operating performance of polymer-electrolyte-membrane fuel cells (PEMFC) for the use as portable energy converter. Especially, mass transport in the liquid and gaseous phase inside the PEMFC are experimentally examined. Water produced during the reaction is measured and liquid water transport in the air flow field of a semi-transparent PEMFC is visualized. Besides this, investigations of different flow field designs are used to develop two portable PEMFC systems. To understand the physical and electrochemical behaviour inside a PEMFC numerical simulations are performed. The used mathematical model is provided by the company Fluent. It verifies spatially resolved current distribution measurements of a PEMFC with straight, parallel gas channels. Thereby, the calculations can be used for the optimisation of the operating performance of PEMFC systems.

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Theoretical models describing the kinetic and evaporation as well as the electrical charge of droplets in a droplet chain generated by a vibrating orifice generator are presented. The models are verified by experimental results. Droplet charge and the electrical current transported by the droplet chain are correlated with the length of the liquid jet. Based on these results, an apparatus for generating neutral or predefined charged particles has been developed, whereby not only the average charge of the particle collective, but also the charge of individual droplets can be defined. The applicability in generating solid particle aerosols by jet dispersion of solutions are disclosed.