DFG - Coordinated Programs
The research activities at our University are enshrined in the engineering fundamental research. An indicator for success in fundamental research and its quality is the allocation of research grants from the German Research Foundation (DFG). So far, four collaborative research centres, four graduate schools, four research units and various priority programs could be set up at the TUHH.
DFG Priority Programs
Collaborative Research Center
“SFB 986: Tailor-Made Multi-Scale Materials Systems - M3”
Head: Prof. Dr. Gerold Schneider
The long-term research goal of the Collaborative Research Center “SFB 986: Tailor-Made Multi-Scale Materials Systems - M3” is to develop experimental methods for producing and characterizing multi-scale structured materials with tailor-made mechanical, electrical, and photonic characteristics. It has been approved by the German Research Foundation (DFG) under the leadership of TUHH in close collaboration with the University of Hamburg and the Helmholtz-Zentrum Geesthacht. Within the SFB 986, 20 project leading scientists work on a cross-disciplinary approach to develop completely new types of materials.
The special innovation potential of the SFB 986 lies in how the materials are assembled: predominantly, from single building blocks of distinct discrete length scales. This hierarchical composition opens up possibilities to exchange building units in a concerted way in order to discretely alter materials properties and, thus, to achieve entirely new materials functions.
In addition to the required experimental methods and based on their results, theoretical materials models are refined. Hence, the SFB 986 not only gains experimental expertise but also a theoretical understanding of how a hierarchical composition determines materials behavior. To this end, theoretical modeling includes atomistic, meso-scale, and continuum models.
For the hierarchical structures, the single building blocks are comprised of polymers, ceramics, metals, and carbon (in form of carbon nanotubes and aerographites). They form core-shell structures or cavities filled with polymers and, in turn, assemble to build up structured and functionalized units from the atom to the macro-scale.
The three project areas of the SFB 986 use different materials systems and vary both the multi-scale structure and the functionalized properties: While project area A focuses mainly on quasi-self-similar structures with multifunctional properties, project area B aims to generate integrated nanostructured multiphase material systems with a structural design that combines strength and functional, especially, electrical, properties. The main emphasis in project area C is on highly ordered hierarchical periodic and aperiodic structures and their photonic properties at high temperatures.
By harnessing the inter-disciplinary potential of the SFB 986, the scientists in the three project areas will develop innovative macroscopic, multi-scale structured materials and components, the properties of which can be changed discontinuously by a controlled exchange of components. If the scientists succeed in implementing this concept, entirely new kinds of materials functions are expected.
DFG Research Training Groups
1570: Porous media with defined porous structure in Chemical Engineering – modeling, applications, synthesis
Coordinator: Prof. Dr. Dr. h.c. Frerich Keil
The present priority program (SPP 1570) has been started in 2011. It is a cooperation of 13 groups from various universities in Germany and abroad. The goal of the priority program is the investigation of recently developed methods of synthesis of porous media with a defined pore structure, augmented by their modeling.
Porous media are ubiquitous in chemical engineering, for example, as catalyst supports, adsorbents, insulation material, membranes or chromatographic columns. From simulations it is well-known that properties of materials may be improved considerably by optimization with respect to given criteria. Not until the last few years, new experimental methods allowed for the targeted synthesis of defined pore structures. Cooperation of chemical engineers and chemists will utilize the new possibilities in chemical engineering.
The optimal porous media for the respective applications shall be developed in close cooperation with chemists who work on the particular problems. In detail the following aims shall be achieved:
- Pore models should be developed, which give insights into processes inside the pores. These models could be network models, inverse pore structures from x-ray data (for example, for amorphous media), or well-defined crystalline structures based on crystallographic data. For particular cases effective pore models may be employed.
- Transport phenomena inside the pores may be described by suitable multicomponent pore models (for example, Stefan-Maxwell equations), heat conductivity equations or molecular approaches (Monte Carlo, Molecular Dynamics, density functional theory (DFT)). Solutions resultant from these simulations are used for the optimization calculations.
- The pore structures should be optimized with respect to particular applications, applying relevant optimization criteria. This will be done by means of modern approaches of convex optimization, genetic algorithms, parallel tempering, etc.
- The optimal pore structures shall be synthesized in close cooperation with chemists.
- The synthesized porous media will be applied for the respective chemical processes.
- New high-resolution imaging processes (Magnetic Resonance Imaging) are to be employed making the liquid distribution inside pores visible, in particular for drying processes and three-phase reactors.
- The synthesized porous media are then to be used for the respective process technology applications, where they should demonstrate their improved properties in experiments. Some applications will only be made economically feasible by new synthesis procedures.
- As overall goal a rational design of pore structures is striven for. Detailed insight into the molecular processes inside the pores, followed by targeted synthesis of optimal pore structures, according to given criteria, should be achieved.
1679: Dynamic Simulation of Interconnected Solids Processes
Coordinator: Prof. Dr.-Ing. Stefan Heinrich
Conversion process in chemical and energy technology consist in most cases of multiple apparatuses, which are interconnected by streams of mass, energy and/or information. This interconnection influences significantly the operating behavior and especially the dynamics of the whole process. Therefore for design and optimization of such processes, especially with respect to saving of resources and energy, it is not sufficient to simulate the separate units independently, but the whole process should be simulated as an entity. For this purpose flowsheet simulation systems are used frequently in the design and optimization of fluid processes. In contrast, similar systems without restriction to certain applications only are not widely available for solids processes. Main reason for this lack of systems and dynamic models is the complicated and complex description of solids with their multivariate and distributed properties.
Therefore, it is the general aim of the Priority Program to develop numerical tools for the dynamic simulation of interconnected solids processes. To reach this aim dynamic models of the many different apparatuses and machines for solids processing have to be developed and to be implemented. Required are physically based predictive models, which allow a sufficiently accurate description of the process, have not too high requirements for computing resources and are widely applicable. With respect to the use within a flowsheet simulation framework, they should not be restricted to certain materials or classes of materials. Furthermore, they have to consistently treat the disperse properties of the solids. These distributed properties are not the particle size only, but may also be e.g. the density, composition, shape or porosity of the particles.
Beside the development of new process models also new and extended models for the description of solid materials and particles are needed. These models are required to deduce information about product quality or required product properties as for example the solubility or flowability of powders from the disperse properties calculated by the process models. Furthermore, the material models are required to determine concentrated parameters identified during the model reduction from easy to measure particle properties.
Simulation of solids processes under consideration of distributed properties leads commonly to systems of population balances, in which equations for the conservation of mass and energy are coupled with equations for the description of the population. For the solution of such systems exiting solvers for univariate systems shall be improved and be extended to the solution of multivariate population balance systems.
The research work of the Priority Program is divided into three areas:
A - New physically based dynamic models of processing units
B - Material models for solids processes
C - Algorithms and process simulation
Within the Priority Program scientists of different disciplines and from different universities will cooperate. The program is planned for a duration of six years and is financed by the German Research Foundation (DFG).
1740: Reactive Bubbly Flows
Coordinator: Prof. Dr.-Ing. Michael Schlüter
The conversion of chemical substances with high selectivity and yield is one of the major tasks in Chemical Process Engineering. For the production processes of many bulk chemicals it is necessary to bring gaseous substances in contact with a continuous liquid phase (e.g. oxidation, hydration and chlorination). In the 1960s Bubble Column Reactors have been developed for this purpose, which allowed an intensive mixing for large reaction volumes and long residence times. In the 1980s an increased amount of Bubble Columns with defined mixing zones (e.g. loop reactors) showed up the potential of specific flow configuration. In the late 1980s an increased detailed consideration of bubbly flows began and started to boom in the 1990s. Once it was shown for single-phase flows that chemical reactions are influenced by the mixing on different time and length scales, large optimization potential was identified for reactive bubbly flows due to the additional transport resistances through phase boundaries and boundary layers. However, multi-scale transport processes with a coupled reaction could not be adequately described so far. With the result, that reaction rates were often assumed and therefore include an unknown part of mass transfer in addition to the intrinsic kinetics. Thus, the transferability of models and the predictive forecast of yield and selectivity are very limited. Up to now, there were neither experimental nor numerical tools with sufficiently high spatial and temporal resolution available to determine the uninfluenced reaction rates.
Due to the rapid development of microelectronics, LCD, OLED and image sensor technology this situation has improved significantly. The experimental determination of intrinsic kinetics and the elucidation of single reactions steps as well as local mass transfer processes are today available through new miniaturized reactors, research methods and measurement techniques, which allow resolving the processes on the smallest time and length scales. In addition tremendous progress was made in the field of numerical simulation through new methods (e.g. consideration of concentration jumps at phase boundaries and interfacial contamination) and the new high-performance computers. To handle the challenges of a predictive process control, these experimental and numerical progresses have to be harnessed for the process technology and mass transfer and reaction steps locally coupled.
The new possibilities for the elucidation of reaction networks and local transport processes as well as for the numerical simulation of gas-liquid interfaces shall be used in the priority program specifically on the systematic analysis of complex technical processes. Therefore it is necessary to characterize the reaction systems as accurate as it is required for the detailed registration of the interaction of gas-liquid mass transfer and reaction. New methods for setting defined mixing ratios (micro reactors, turbulence generators) shall here also be used, as new measurement equipment (e.g., Rotary Chamber, Taylor-Flow Capillaries) and new analytical methods (e.g., Resonance Raman, Coherent Anti-Stokes Raman and Two-Photon Spectroscopy). In the numerical simulation, new methods for the calculation of mass transfer and the implementation of reactions are necessary (e.g. dynamically adapted meshes in combination with parallel computing techniques). For the research program experimental and numerical methods should therefore be equally developed and applied to the analysis and calculation of reactive bubbly flows to allow a predictive forecast of yield and selectivity for chemical reactions overlaid with mass transfer limitations.
Explicitly excluded are basic investigations exclusively on single bubbles, on the phase transition (condensation/evaporation/boiling), on three-and multiphase flows, on particulate flows, on two-phase flows in porous media and the exclusive new development of measurement techniques and numerical methods.