Research in Power, Process, and Environmental Engineering

Analysis, development and optimization of engineering systems in the area of power, process and environmental engineering can only be successful if fundamental physical phenomena within machines and devices are well understood, as well as effective and innovative numerical methods combined with experimental methods are developed and regularly improved. In this field of research transport phenomena in fluids and solids with emphasis on multi-component multi-phase reactive flows present the main experimental and computational challenges. In the field of advanced numerical models for computation of two-phase flows further development and advanced application of novel interaction models for numerical simulation of dilute dispersed two-phase flows by the Lagrange-Euler approach will be conducted, including particle-fluid, particle wall and particle-particle interaction for the case of non-spherical particles. In the Eulerian part (fluid flow) development of a novel point source particle-fluid interaction model in the context of the Boundary Element Method will be developed, which can be applied to momentum transfer as well as heat and mass transfer from particles. The developed particle models will be implemented in detailed studies of transport phenomena in process flows, including particle coating devices, spray and fluidized bed dryers as well as in pulmonary delivery of drugs. Numerical models of unsteady and inhomogeneous transport problems in fluid flows will be extended to nanofluid flow modelling in porous media. In environmental engineering transport of particles in fluid flows will be in the centre of the investigation, especially modelling of sedimentation in a secondary clarifier of a wastewater treatment plant and modelling of sediment transport in estuaries and other types of surface water flow. In thermal engineering research will focus on development of computational model for full scale numerical simulation of the process of vial lyophilization, development of numerical techniques for solving direct and inverse problems in dynamic thermography and development of novel controlled cooling/heating testing device for validation of the novel computational tools. The field of reactive flow dynamics of combustion processes will be covered with the development of numerical model of combustion process of solid fuels in appliances with separation of air and fuel supply, models of the heterogeneous transformation of solid fuel into gaseous products, as well as with study of mechanisms for the production of pollutants. Possibilities of using new additives to diesel and alternative fuels to improve the characteristics of high-pressure fuel injection systems within the common rail engines will be studied experimentally and numerically. In studies of cavitation in hydraulic machines Pelton turbines will be studied with a special emphasis on prediction of cavitation erosion as well as prediction of cloud cavitation in water turbines and pumps.

Understanding and ability of prediction of characteristics of technical systems with prevailing turbulent and multiphase flows is based on deeper knowledge of transport phenomena in these flows. The development of new and accurate methods of computer based simulations of transport phenomena, which greatly exceed the quality of results of classical, on empirical realizations based engineering calculations, is therefore of prime importance for the further development of engineering sciences in the field of power, process and environmental engineering. In the field of development of new numerical methods in the framework of the Boundary Element Method we will developed targeted accurate and innovative models of processes in process and environmental engineering, as well as further improve computer and memory demands of the method. The development of advanced models for heat and mass transfer in dispersed flows will lead to a detailed insight into complex flow, temperature and component (species) fields in heat and mass transfer separation devices, waste to energy plants as well as internal combustion (IC) engines. In the field of the use of numerical methods for computation of flows in turbomachinery the scientific focus is on the study of transient and cavitating flows. With this we enrich our knowledge of different stable (partial loading, optimal working point, full power) as well as unstable operating regimes (start, runaway). Based on increasingly rigorous environmenal legislation and the problems in the use of fossil fuels there exist a need to search for new methods of use of alternative fuels in internal combustion engines. The newly developed mathematical models for numerical simulation of injection process and combustion will reduce excessive experimental testings and enable a faster development of more efficient and environmentally friendly motors. The equilibrium model of multistage gasification of solid waste on a grate will further be improved to enable a more detailed analysis of combustion characteristics in primary and secondary chamber in the device for thermal use of solid waste. The thermography based diagnostic methods will be enriched by targeted solution of inverse bio-heat transfer problems, especially in the case of biological tissues, as found in medicine applications.

Process engineering and pharmaceutical industry shows large needs for numerical modelling of transport phenomena in dispersed phase of solid particles as well as in modeling of lyophilization. As application example of spray drying of solid particles in flow of continuous fluid will be used (drying air) with three stage drying with better forecasting of energy used of this energy wasteful process. Also, computational model of virtual industrial scale liophilizator will be developed. This will be continued with use of research in numerical field with heat transfer and water transport model development of car lightnings, in particular as Slovenia already features two important manufacturers, one of which (Hella Saturnus) already cooperates with members of our research group. Water power is the most important among of renewable energy resources without CO2 footprint. Slovenia has a long lasting tradition as well as plethora of knowledge and experience in developing and manufacturing of water turbines with emphasis on Kolektor Turboinštitut, our partner in research program. If results are to be used in the market one need exceptional characterics of machines and reduction of cost. Both can be achieved with development of new numerical methods with better description of turbines. There are also number of smaller projects where physical models manufacturing does not justify the cost so the only alternative really is numerical check of requested characteristics. Internships by students from Maribor and Ljubljana provides for popularity of numerical methods in industry, and at the and at the same time result in diplomas, master of science works and doctoral  dissertations in the area of numerical analysis of hydraulic machinery flows. Heating, cooling and climatization (HVAC) will be focused on optimization of efficiency of convection heating with taking into account outside and inside temperatures for each heating unit, in particular in residential and business buildings. Environmental engineering research will focus on development of methods of heat treatment of waste and analysis of fuel suitability, said fuels manufactured from household waste. By addressing the issue we will contribute to better Slovenia's treatment of this waste. Multiphase numerical methods will be used for study of biological systems (treatment plants) as microorganisms in these flows usually behave as particles. In case of ground water numerical methods will be used for simulation of transport of pollutants in ground water.