<p style="text-align: justify;">The aim of this paper is to perform a dynamic analysis of a large industrial mixer used for mixing liquids inside a vertical tank. The analysis is performed numerically using software tools SolidWorks and Ansys for finite element method analysis. A comparative analysis of results obtained from both software platforms is presented. Although there are discrepancies in the results due to software differences, the overall results are satisfactory. The largest discrepancy was noticed in the maximum equivalent stress on<br />the tank roof. The structure exhibits elastic behavior under oscillating loading, keeping its integrity. While deficiencies in 3D modeling affect stress distribution, natural frequencies in software coincide with analytical calculations. Following loading, the structure settles as expected, indicating well-established dynamic analysis. Despite challenges in stress<br />localization, the study confirms the validity of the conducted analysis, considering the complexity of the structure.</p>

<p>The heating of residential and commercial premises in urban areas during winter periods is mostly performed by use of the heat energy which is distributed through central or city heating systems. Water, steam and gas are used as the basic working media in these heating systems. The thermal energy that is used in the city of Kakanj and its surrounding<br />settlements is produced in the Thermal Power Plant Kakanj and then delivered to the final consumers, which are usually located at relatively large distances from the heat source.<br />This paper describes the district heating system in Kakanj and the process<br />of heat energy distribution carried out by JP &bdquo;Grijanje&ldquo; d.o.o. Kakanj.<br /><br /></p>

<p style="text-align: justify;">As the result of combustion process in boilers of the Thermal Power Plant &bdquo;Kakanj&ldquo;, flue gases develop, which are undesirable for the environment, for people living in the plant neighborhood and for flora and fauna. In order to perform environmental protection a lot of efforts and organizational activities should be put in action and significant resources should be made available. Flue gases from the plant boilers are filtered and discharged in the environment after passing flue channels and the chimney. The Thermal Power Plant &bdquo;Kakanj&ldquo; has used 300-meter chimney for flue gases discharge for a long time. During the<br />overhaul of block 7 and reconstruction of 300-meter chimney in period September-December 2014, it was necessary to redirect the flue gases from blocks 5&amp;6 to the 100-meter chimney. This task required certain reconstruction of existing installation and calculation of 100-meter chimney capability. The performed flue channels reconstruction and calculation of operating parameters of 100-meter chimney are presented in this paper.</p>

This paper aims to present and compare the damage identification results of two methods proposed by the authors for beam-like structures. Both methods use the same numerical and regression models as well as the experimentally obtained values of the beam bending frequencies. The difference between these methods lies in the final stage of their usage. The first method relies on finding three closest intersection points of frequency curves and the second method is based on finding a minimum value of the proposed frequency related functional. The results of damage identification for 28 damage scenarios using the proposed methods are presented and compared in this paper. The comparison showed that the accuracy of both methods is almost the same and depends mostly on the input data quality.

After passing a certain filtering process, the flue gases generated during fuel combustion process in the boiler of a thermal power plant are discharged into the environment by flue channels and a chimney. For a long time, the Thermal Power Plant "Kakanj" has used 300-meter chimney to discharge the treated flue gases into the environment. During the overhaul of the block 7 and reconstruction of 300meter chimney, which were done in the period September-December 2014, it was shown necessary to redirect the flue gases from blocks 5 and 6 toward the 100-meter chimney. This paper presents the calculation of operating parameters and design analysis of 100-meter chimney in order to determine whether blocks 5 and 6 could work without problems when connected to 100-meter chimney. Also, the installation of new flue channels from blocks 5 and 6 to the 100-meter chimney is shown.

Reduction of undesirable particles emission into the air is one of the main tasks for the environment protection. A particular problem is the emission of solid particles from the flue gases that are the product of combustion in the thermal power plant. There are several ways to reduce the emission of those undesired particles, such as using the separators, cyclones, dust chambers, various filters and so on. This paper presents the process of removing solid particles from the flue gases by installation of bag filters type FVU-P in blocks 5 and 6 of the Thermal Power Plant "Kakanj". The basic characteristics and components, application area, principle of operation and automatic ways of shaking bags off are presented in the paper as well as the effects of its installation to the air pollution parameters.

Damage in a structure is a local perturbation of its physical characteristics, i.e. its stiffness, mass and/or damping. Consequently, damage alters dynamic characteristics of the structure such as natural frequencies, damping value and mode shapes associated with each natural frequency. This is the base of vibration based structural health monitoring techniques. In this paper characteristics of mode shapes are investigated for identifying the location of damage in a beam structure. Cantilevered beam model is investigated numerically by use of finite element method. Slope and curvature of displacement mode shapes differences (between intact and damaged structure) were calculated using a central difference approximation. The results have shown that changes in the mode shape characteristics are good indicator of damage location and severity, and hence can be used to detect damage in a structure.

This paper addresses the problem of damage identification in beam-like structures on the base of bending frequency changes. The identification of damage location and its depth is performed by use of regression relations between changes in natural frequencies and damage parameters. Input data for establishing the regression relations are collected using numerical analysis (FEA) of the beam structure with and without damage. The damage is simulated as a narrow open notch perpendicular to the beam axis. The efficiency and limitations of the proposed technique are assessed through a series of damage scenarios.

SUMMARY The developments in Computational Fluid Dynamics (CFD) during the last decade have enabled accurate and reliable calculation of velocity, pressure and temperature fields in fluid flow through different mechanical parts and systems. The quality of results numerically obtained depends on the quality of finite volume mesh, i.e. the number and type of finite volumes that are used in mesh generation. The numerical analysis of stationary oil flow through chambers and channels of cylindrical piston distributing valve was performed and this paper presents the influence of the number of finite volumes and mesh refinement on Δp-Q characteristics of the valve. 1. INTRODUCTION Cylindrical piston distributing valve is one of the most important control and regulating components of hydraulic systems. In classic hydraulics the main function of distributing valves is to control the flow of fluids. Additionally, in proportional and servo hydraulics distributing valves have a great influence on kinematic, dynamic and fluid pressure characteristics. The use of hydraulic fluid systems with classical, proportional and servo distributing valves is very common and important in industrial applications. Consequently, number of engineering and scientific investigations deal with the analysis of distributing valves, [1]. However, Computer Fluid Dynamics (CFD), i.e. numerical analysis of fluid flow through channels and chambers of cylindrical piston distributing valves and their operating performances has been used only in a few special cases. The analyses were performed on simple two-dimensional models using some of the special programs developed for simulations. For instance, A.Kilchmann used the finite difference method in his investigations. On the basis of R.N.Clark investigations, M.Y.Guo and K.Nakano used the boundary elements method to analyze the compensation of fluid force acting on a valve piston. Also, T.Tsukiji used numerical analysis in investigation and simulation of the fluid flow by discrete vortex method. In recent years many authors have used numerical methods such as Finite Element Method (FEM) and Finite Volume Method (FVM) to analyze the fluid flow in cylindrical piston distributing valves. Some of those who used FEM are: