Cleaning mechanisms of immersed systems
In future the offer of fresh water in many regions on earth runs short. Various studies predict an increase of 55% in water consumption. The highest increases is expected in the manufacturing sector, the thermal electricity generation, and in private household. Especially in food industry and pharmaceutical industry as part of the processing industry the majority of water consumption is used for cleaning processes. Based on the combination of available optimisation potential of current cleaning processes, rooted on a better understanding of effect mechanisms and the huge increase of water consumption, there exists a substantial cost-saving options of the water resources.
However, cleaning processes of fouled organic material on heat transfer surfacesisa complex interaction of interfacial interactions, mass transfer, heat transfer, fluid forces and chemical reactions, whichis presently not fully understood. The main objective in this research project is to achieve a fundamental knowledge of the cause-effect relationships in the cleaning of immersed systems. Wheyprotein in the form of Whey Protein Isolate (WPI) gel are to be used as a representative model fouling system. The research project is divided into three parts. The first part comprises the investigation of all material properties which are relevant for a cleaning process, specifically strength, viscoelastic characteristics, diffusion coefficient, surface topography, adhesion and cohesion force. These material parameters will be used in the second part of the project. Here a fundamental database for a continuum-mechanical finite element model of the fouling layer will be set up. The fluid phase will be simulated with a fluid-structure interaction model (FSI) model, so that the cleaning process of WPI can be simulated. To validate and improve the FSI model, two established methods, namely fluid dynamic gauging (FDG) and local phosphorescence detection (LPD), are used in the third part. The FDG method enables to investigate the three stages of the cleaning process, swelling stage, uniform stage and decay stage. In combination with a particle size analyser the particle size of removed particles can be determined. With the LPD method, it is possible to locally determine the cleaning time in different flow geometries under laminar and turbulent flow conditions. By correlation of the specific light intensity and the fouling layer thickness a removal rate as well as a change of the layer thickness can be quantified. The modelling approach will be developed further and based on this FSI model a tailored and system-specific cleaning strategy can be designed and validated. Furthermore well-established methodological approaches will be available, which can then be applied to any fouling layer.
Publications:
2020
J. Liu, H. Wiese, W. Augustin, S. Scholl, M. Böl
Mechanical comparison of milk and whey protein isolate fouling deposits using indentation testings
Food and Bioproducts Processing, 122, 145-158, (2020) [Link]
J. Liu, M. Helbig, J.-P. Majschak, M. Böl
Whey protein gel - experimental testing and modelling of wire cutting
submitted, (2020)
Presentations:
2019
J. Liu, H. Wiese, S. Scholl, W. Augustin, M. Böl
Comparison of the mechanical properties of milk fouling and whey protein fouling
Jahrestagung der Gesellschaft für Angewandte Mathematik und Mechanik (GAMM), Vienna (Austria), February 2019
2018
J. Liu, H. Wiese, J. Dittmann, W. Augustin, S. Scholl, M. Böl
A comparison of the mechanical constitutive behaviour of milk protein deposits and fouling deposits from raw milk
Fouling and Cleaning in Food Processing, Lund (Sweden), April
2018
M. Böl
Biomechanics - Multi-scale/field experimental approaches
University of Kassel, Kassel (Germany), April 2018
2017
M. Böl
Advanced experiments on biological systems at different length scales
ETH Zurich, Zurich (Zwitzerland), December 2017