This paper presents thermodynamic (energy and exergy) analysis of backpressure (BPT) and condensing (CT) steam turbines from cogeneration system. Based on the measurement data from exploitation it is performed calculation of main operating parameters for both turbines and its comparison. Analysis shows that BPT develops significantly lower mechanical power (22821.90 kW) in comparison to CT (30893.10 kW), but also BPT has more than four times lower energy and exergy power losses when compared to CT. Due to much lower losses, BPT has significantly higher energy and exergy efficiencies (93.26% and 94.95%, respectively) in comparison to CT (82.63% and 83.87%, respectively). Energy and exergy power of a steam flow related to both observed turbines show that the BPT is the dominant heat supplier for all heat consumers inside the cogeneration system.
Machines. Technologies. Materials.
Vol. 16 (2022), Issue 2
Table of Contents
Condition monitoring of production equipment is an important task in any industrial production. This article describes the features of laser alignment of worm gearboxes and its effect on the temperature and vibration level of rolling bearings. The necessity of periodic temperature and vibration signal measurements and analysis of bearing’s condition for timely forecasting of equipment condition and planning of repairs, is also justified
Influence of the forging process in step-wedge-shaped strikers on the destruction nature of the deformable metalpg(s) 52-53
The paper investigated the effect of cyclic deformation on the destruction nature of workpieces during broaching in step-wedge strikers. AISI 1020 was chosen as the workpiece material. According to the experiment results, the influence of turning and cycles number on the values of impact strength was carried out. Fractography analysis of the fracture surface structure was also conducted.
The effect of different heat treatments on the microstructure and mechanical properties of the C45 and S355J2 steel forgings has been presented. Samples of the same forgings, but subjected to the different heating treatments, were prepared and tested by using opticalmicroscopy, tensile machine, and hardness tester. It was observed that the requested mechanical properties of the forgings and uniform structure can be achieved by determining the appropriate heating treatment parameters.
Deposition of ZrO2 thin films obtained by sol-gel method on monolithic composite with layered structure of Nb30Ti/Alpg(s) 58-61
The present publication is aimed at obtaining a stable sol from ZrO2 stabilized with Y2O3. The substrate on which the layers are deposited was developed by a team from Russia and is intermetalite with a layered structure Nb30Ti/Al. Deposition was performed by spinning with a Spin Coater Ossila L2001A3. The deposition sequence of the layers lasts 30 seconds. The finished carrier is dried at 120°C in an oven. It is heated in a laboratory furnace at 350oC. The results were characterized by XRD and SEM analyzes.
Methods for implementing the concept of energy and technological compliance of components in the technology of highly filled compositespg(s) 62-65
Structural and technological aspects of obtaining and processing functional composite materials based on polytetrafluoroethylene are considered. It is shown that, due to the peculiarities of the molecular structure of matrix polymers, within the framework of the traditional technological paradigm, prerequisites are created for the implementation of a structural paradox, which manifests itself in a decrease in the parameters of the stress-strain and tribological characteristics of composites with an increase in the degree of filling. Within the framework of the concept of multilevel modification, methodological approaches to the implementation of the energy and technological compliance of components, which reduce the negative impact of the structural paradox, are considered.
Titanium alloys due to their good properties are increasingly used in biomedicine. However, in order to improve certain properties, titanium-based alloys with new chemical compositions are designed. In order to be characterized in a satisfactory manner, they must first be adequately prepared. In this paper the two most influential parameters were varied: grinding time and force, while the speed of rotation of the grinding wheel was constant. After grinding with the highest gradation of grind paper, the samples were observed under a light microscope to determine the condition of the surface. Then their hardness was determined by the Vickers method with different indenter loads. After that, the samples were polished under the same conditions, and their hardness was determined again. The obtained hardness values were numerically analyzed and the corresponding functional dependences of the measured hardness on the grinding parameters (time and force) and on the indentation force were determined.
Analysis of mechanical properties and microstructure of Ti-Al-C composites after spark plasma sinteringpg(s) 70-73
Titanium rich alloys of Ti-Al-C and Ti-Al-B system was synthesised by Spark Plasma Sintering (SPS) and Field Activated Pressure Assisted Sintering (FAPAS) methods with altering sintering temperatures in the range of 950°C-1020°C with different current for the duration of 5 minutes. The initial powders of the composite 85%Ti and 15%Al was processed by High Velocity Energy Distribution (HVED) in a solution of kerosene at the specific energy of 25MJ/kg to reduce the size of the particles to nano-scale. This method of using different parameters of production technology have helped to analyse the most efficient, energy saving, and less waste generation technological process with improved mechanical properties. The metal-based samples were examined by optical and electron microscopy. Mechanical properties of composites were determined by measuring microhardness.
The aim of the investigation was to determine the dependence between parameters of production technology and properties of Ti-AlC composites.
Effect of work hardening and recrystallization annealing on structure and properties of low-carbon steel wirepg(s) 74-81
In this work it was studied the influence of low-carbon steel wire annealing at different temperatures from 500 to 750 °C that was obtained by cold drawing on its structure and properties. It was sown that bigger work-hardening during the drawing process leads to the decreasing of collective recrystallization starting temperature, which could resulting in obtaining less plastic properties than are appear after lower annealing temperatures with additional loss of strength. The found effects give valuable information for cases when it is desirable to obtain the minimal strength or the maximum plasticity of the wire.
Geopolymers based on natural zeolite clinoptilolite and addition of up to 50% metakaolin were synthesized using binary sodium/potassium alkali activator. The influence of metakaolin addition was evaluated on apparent density, water absorption, relative mass loss after watering and microstructure (XRD) of the prepared geopolymers. The addition of metakaolin greatly influenced the physical and mechanical properties of the obtained geopolymers. Minimal/optimal metakaolin addition was estimated to 30% in the respect of sufficient strength (11 MPa) and the high price of metakaolin. The resulted geopolymer based on natural zeolite and metakaolin (30%) contained residual unreacted clinoptilolite which could be beneficial for properties of future geopolymer products. Potential applications of obtained geopolymer-clinoptilolite agglomerates are: waste or radioactive water decontamination, passive cooling systems, plasters in residential buildings, etc.