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Engineering efforts to handle contemporary energy supply challenges and mitigate pollutant emission lead towards more complicated systems. Power plants are supplementing with additional processing units, alternative production modes and higher level of automation. Wind and solar sources, biomass combustion, gasification, carbon capture and storage (CCS), and cogeneration have appeared as important players in the energy systems. The increasing complexity comprises a risk that the systems become less manageable and less stable than currently. Traditional steady-state engineering methods cannot fully address these challenges that are inherently dynamic in their nature. Dynamic process simulation appears as important tool to the systems design and optimisation tasks. A large variety of dynamic process modelling and simulation approaches has been presented recent years. This paper presents a brief review of methods and simulation packages that are generally applied for studying energy systems' transient behaviour. A CCS capable power plant is presented as an example of utilizing dynamic process simulation for virtual evaluation of a novel electricity production concept. The modelling was performed using two simulators Apros and Aspen Plus Dynamics, which were linked together for dynamic simulating the full chain of cryogenic oxygen distillation, oxy combustion, turbine islands and carbon dioxide purification and liquefaction operations.

The article presents the application of the CFD FVM model for thermal simulation of the GMAW hardfacing process. The paper focuses on heat transfer aspects of welding process like distribution of temperatures, heat transfer from electric arc, thermal effects of melting and solidifying of metal. Because detailed CFD and thermal analysis of welding process is computationally expensive, the modified, faster approach has been proposed to obtain realizable compromise between accuracy and calculation efforts for engineering heat transfer analysis. It allows getting the thermal simulation closer to engineering practise as a base for structure analysis. The model has been tested and validated against thermography measurements. The procedure of thermography measurements and validation has been presented in the article. Results showed high reliability of proposed approach, particularly for heat transfer around electric arc. The developed model can be applied for various FVM codes and useful as a part of multi physics analysis.

Organic Rankine Cycle (ORC) technology is nowadays considered as interesting option for utilization of local biomass resources. The number of plants worldwide is constantly growing within typical range of electric power output form 0.2 to 3.0 MW. In such systems biomass combustion chambers with step or vibrating grates are used. Heat is transferred to the thermal oil in a separate spiral heat exchanger. The biggest problems in such system are variable and inaccurately predictable properties of biomass that directly influences operation of combustion equipment, and thus the performance of entire cogeneration plant. In this paper experiences from two plants are presented. The plants are located in Krosno (Poland) and in Ostfildern near Stuttgart, Germany. In the first one high quality wood chips are used whereas the second one is powered by low quality biomass with the mass ash content approaching 18%. Although similar, both plants use different strategies to control the combustion process. Long term measurements are used to develop biomass combustion models in the plants. The paper also presents results of implementation of the online optic measurement system for monitoring of biomass properties such as LHV, ash and water content.

Despite very rapid development of science in the recent years, the phenomena occurring in the electric arc have not been fully recognized. The main reason for this situation is their the complexity as well as very high temperatures. This paper presents the results of numerical calculations of phenomena which occur in the welding arc. The CFD Fluent package was used for modelling the following phenomena in the electric arc: melting, solidifying, generation of heat and multiphase flows. The 3D Model of a 50 × 30 × 6 mm metal plate segment padded with the use of the MIG method with a wire of 1.2 mm in diameter was developed. The paper focuses on presenting the distribution of temperatures in time, the process of melting and later solidifying of the material, as well as on the transport of the material from the arc to the padding weld. It also shows the initial verification of the model by comparing the results with a picture recorded by thermovisual camera.

Identification of thermal resistance of the gas-gap between the ingot and mould, as well as the heat flux distribution on the phase change from the solid side during continuous casting of metals is the subject of this article. Analysed parameter estimation problems of the steady-state heat conduction belong to the group of inverse problems. The presented work shows the possibility of applying the least square adjustment method with a priori data for the identification of thermal resistance, the interphase location as well the heat flux distribution on the phase change from the solid side and the temperature field within the ingot and mould. The most important feature of the approach is that the unknown thermal resistance of the gas-gap is obtained from the temperature measurements at a number of sensors located in the wall of the mould, and some sensors located in the ingot, by solving the appropriate inverse problem. The validity of the solution of the inverse problem is checked by comparison with the re...

Numerical model of the flow phenomena in the flotation machine is presented in the paper. The process of flotation consists of a number of phenomena which provide serious numerical difficulties. These include rotation, multiphase flow, foam formation etc. To the knowledge of authors, there is no complete numerical model available for the flotation machine. The long term task of the project is to develop the model of processes taken place in the flotation machine. Such a model would be very helpful designing these machine or during their modernization. In the paper, a two-phase flow of water and air in the flotation cell is analysed. For this purpose the commercial package ANSYS-Fluent was employed. The Interfacial Area Concentration method was used to model the two phase flow.