Turbine Power Plant Research Articles

Pressure Drop Analysis of Turbine Housing Model with Circular Sliced Pipe for Micro Hydropower Generation

Energy independence is a government program aiming to meet society's energy needs evenly. Steps to increase energy independence in the new and renewable energy sector include hydro-energy generation. One of the important components of a hydro generator is the penstock pipe and turbine housing, which channels water and then pushes and drives (spins) the turbine with the flow of water to produce electrical energy. The turbine housing flow design innovation must provide a function as an optimal fluid conductor by minimizing the resistance that occurs when fluid flows towards the turbine housing and rotates the turbine optimally. The scope of this research includes analysis of the phenomenon of energy loss flowing in circular pipe slices in hydroelectric power plant turbine housings with influencing factors such as friction, turbulence, and flow resistance, as well as measuring the pressure drop in circular pipe slices. The model developed is a circular slice bend with angles of 180 degrees, 270 degrees, 360 degrees, and 450 degrees, taking into account the optimal curvature ratio (R/D) of 3.5. Based on previous research, 90-degree wedge bends with many slices (n_(90-degree)) 4 to 6 or  4 and pressure drop coefficient (C_(pd-th)) obtained 180-degree (0.333 – 0.200), 270-degree (0.445 – 0.277), 360-degree (0.527¬ – 0.339), 450-degree (0.587 – 0.390) with a bend length L, an elevation reduction angle  and a 1.5D upstream-downstream elevation difference to avoid contact between the upstream and downstream bends. The results obtained from this research are the slice modules that can be used and the resistance coefficient values that arise from the slice modules. The more slices selected according to the angle of inclination chosen, the smoother the resulting circular bend shape and the lower the resistance value, but the work will be more difficult. The most optimal slice module is the number of slices that allow its implementation, and the resistance coefficient is small. By knowing the optimal resistance coefficient value, the resulting pressure drop can be predicted to maximize the thrust to rotate the turbine.

Further Improvement of the Mathematical Model of Thermo and Gas-Dynamic Processes in a Turbine without Working Blades of Some Stages

The current state of the Ukrainian power system is characterized by significant stress and a shortage of generating capacities. Restoration and implementation of new generating capacities require a huge amount of appropriate resources and a lot of time. The optimal low-cost and relatively fast option for improving the state of the power system may be the temporary use of damaged power equipment after taking appropriate preventive and repair measures. The emergency state of steam turbines of many power plants requires a special tool for assessing their efficiency and power, as well as the possibility and feasibility of their further use after damage. This paper gives consideration to an improved mathematical model of thermo and gas-dynamic processes in a turbine without working blades of some stages. The test calculation data obtained for the flow parts of the cylinders of various steam turbines in the absence of working blades were presented both for individual stages and the groups of stages. Characteristic patterns of the effect of the location of the stage without working blades in the turbine cylinder on the efficiency of the flow part have been established. The greatest decrease in the efficiency and power of the cylinder occurs in the case of the absence of working blades in the stages located closer to the cylinder head. The lowest efficiency and power losses are observed in the absence of working blades of the last stage. In the nozzle cascades of the stages located directly behind the stages without working blades, the levels of energy losses are increased significantly. The use of the developed mathematical model allows us to find solutions to increase the efficiency of turbines with missing working blades in some stages by changing the geometry of the appropriate nozzle cascades.

From vapor to liquid: Unlocking the potential of Tesla turbines in ORC power plants with variable steam qualities

From vapor to liquid: Unlocking the potential of Tesla turbines in ORC power plants with variable steam qualities

Numerical investigation and optimization of heterogeneous-homogeneous coupled condensation in steam turbines of tower solar power system

The significant potential for stage efficiency improvement is in steam turbines of solar thermal power plants, which operate in difficult atmospheric conditions contributing to the high pressure in the condenser and steam impurities. Presented study aims to examine the influence of three steam impurities on the condensing flow through turbine stage rotor. Firstly, the modified condensation model is validated using experimental data. Next, the flow characteristics and losses of pure steam and steam containing heterogeneous particles in three-dimensional turbine are investigated separately, and the effects of particles on the flow process and system performance are analyzed. Finally, the effect of backpressure on the condensation flow and the turbine performance is investigated. The results reveal that homogeneous condensation predominantly occurs at higher blade height, NaCl particles have the most significant impact on condensation. At a particle concentration of 10151/kg, the thermal efficiency of heterogeneous condensation on solid particles and tiny droplets increases by 1.6 % and 2.3 %, respectively, compared to homogeneous condensation. Conversely, NaCl particles exhibit a reduction of 0.2 %. Lastly, by strategically raising the backpressure, it is feasible to decrease the humidity on the final stage blades, enhancing thermal efficiency and ultimately optimizing tower solar power generation system operation.

Electromagnetic–thermal–mechanical coupling analysis of bent rotor straightening via electromagnetic induction heating

Abstract Rotors of steam turbines in power plants can be locally deformed by undesired situations, such as rubbing between the rotors and stationary parts. A straightening process is required to correct bending without causing additional damage because a rotor bending displacement of approximately 0.15 mm can stop turbine unit operation. In this study, a numerical framework was established to simulate the straightening process using electromagnetic induction heating, which is straightforward and economical among the methods for straightening bent rotors. The straightening process involves complex coupling of electromagnetic, thermal, and mechanical phenomena. For efficiency, sequential coupling was used in the simulations, dividing the multiphysics phenomena into electromagnetic–thermal and thermal–mechanical fields. The temperature distributions resulting from electromagnetic induction heating were calculated through two-way coupling of the electromagnetic–thermal analysis. The thermal deformations of the rotors were obtained by solving the coupled equations for the thermal field obtained from the electromagnetic–thermal analysis and the mechanical field. Using the established numerical framework, the thermal–mechanical behaviors and straightening mechanisms of bent rotors were investigated. Furthermore, the effects of process parameters, including the direction of gravity and heating and cooling conditions, on the straightening performance were determined. Appropriate parameters were identified to achieve the desired straightening performance with final bending displacements of less than 0.1 mm for bent rotors with initial bending displacements of 0.15–0.3 mm. For a rotor made of A182 F11 Class 2, the best straightening performance was obtained by heating the rotor to a maximum temperature of 650 °C for 20 h under insulation, followed by natural cooling. The simulation results revealed that the straightening performance can be improved when the rotor is rapidly heated to a high maximum temperature and cooled immediately, as long as the temperature conditions do not cause phase transformation or unintended plastic deformation of the bent rotors.

Virtual 3D modeling of thermal power plant turbines based on bilateral filtering algorithm for point cloud data

Abstract Point cloud segmentation and recognition for virtual 3D wind turbine modeling in thermal plants are disjointed, limiting coverage and elevating mean square error. A design leveraging bilateral filtering of point cloud data for virtual 3D wind turbine modeling is proposed to address this. This approach encompasses data acquisition, preprocessing, and multi-level segmentation to enhance coverage. Bilateral filtering is then applied to calculate the 3D model, with edge correction and verification. Tests reveal that compared to traditional k-means clustering, reduced project space, and hybrid filtering methods, the proposed bilateral filtering algorithm significantly reduces mean square error, maintaining it below 10, demonstrating improved stability, safety, and practical value for thermal plant fan modeling.

Understanding Solid Oxide Fuel Cell Hybridization: A Critical Review

A holistic literature review of 399 articles is presented on hybrid solid oxide fuel cell (SOFC) systems and taxonomized through a unique classification methodology that considers primary energy sources, component configurations, system outputs and relevant analysis. In the reviewed research articles, primarily four different types of technologies are used to complement the energy production of the fuel cell stack. As a result, four respective categories were established in terms of the coupling components, inclusive of (1) wind turbines (WTs), (2) solar systems (SS), (3) thermal power plant turbines (TPPTs) and (4) piston engines (PEs). Additional classification was needed to further subdivide the evaluated system configurations, due to the wide spectrum of system outputs encountered in the reviewed literature. That involved (a) electrical power generation (PG), (b) four types of cogeneration (CG), (c) four types of trigeneration (TG) and (d) two types of multigeneration (MG). Depending on the type of assessment in respective research, literature was further categorized as computational, experimental, or both computational and experimental. The most prevalent hybrid system amongst the 102 designs, as adapted from the reviewed literature, is the SOFC/gas turbine (GT) application, with the overwhelming majority producing exclusively electrical power output. The particular system is physically demonstrated in an existing 220-kW experimental facility established by the National Fuel Cell Research Center (NFCRC). The identified systems were predominantly computationally examined and research focused on operating conditions around specific design load ratings. Energy, exergy, economic, and environmental assessments were typically followed by sensitivity studies in the reviewed literature. The primary decision variables in most cases revolved around SOFC operating conditions, such as temperatures over 1000 °C as well as elevated pressures. Those resulted in the deterioration of the electrochemical cell and failed to be addressed by the majority of encountered studies. Improvements in the conversion efficiency of PG applications were enabled by natural gas (NG)-fed pressurized SOFCs, directly coupled to GTs. The most efficient power configuration in terms of thermodynamic performance was achieved by coupling PEs to SOFCs and a metal hydride reactor (MHR) to unlock a maximum net system efficiency of 79.54%. CG systems integrating solar cells (SCs) and photovoltaic panels (PVs) to SOFC subsystems can result in a combined efficiency of approximately 90% and sustain this over a broad energy demand range. TG systems incorporating gasifiers to SOFC/GT subsystems achieved a combined efficiency of 93%, whereas the optimal combined efficiency in MG configurations was identified at 79.5% by coupling SCs to the SOFC/GT/organic Rankine cycle turbine (ORCT) subsystems. In terms of cost-effectiveness, configurations that relied on increasing levels of renewable energy (RE) technologies resulted in high overall levelized cost of electricity (LCOE). This cost was increased further when power storage units were deployed to address wind and solar intermittency challenges. Configurations classified under TPPTs operating on low carbon-content fuels were preferred in terms of providing lower LCOE, while applications operating on gasified biomass and coal blends should deploy additional CO2 capture and storage units to mitigate respective emissions.

COMBUSTION OF HYDROGEN IN OXYGEN-STEAM MIXTURE FOR INCREASING THE STEAM TEMPERATURE OF POWER PLANTS

In the work the problems that arise at combustion of hydrogen in oxygen-steam mixture for the purpose of combustion products (steam) mixing for heating steam, which is planned to be used in steam turbines of power plants were researched. The main problem is the formation of underburning H2 and, accordingly, the presence of O2, which have a negative effect on metals, and it will also prevent steam condensation in the condenser was determined. For solve this problem, calculations of the equilibrium concentrations of chemical reaction products in the combustion zone depending on the amount of ballast steam added to the oxidizer (oxygen) for the initial conditions: T0=528 K, p=0.1 MPa; T0=​​528 K, p=3.1 MPa; T0=​​584 K, p=10 MPa were made. The corresponding adiabatic temperatures were calculated. The dilution of the oxidant (oxygen) with steam significantly decreases the adiabatic temperature (Tb) and reduces the equilibrium concentrations of other substances in the combustion zone, but at the same time the laminar flame propagation velocity (SL) also significantly decreases was established. It is important when a certain concertation of ballast steam is achieved (the final percentage is determined by the design of the burner) there will be a sharp deterioration of combustion or even the formation of a flame will be impossible. The principal design of the hydrogen-oxygen-steam combustion chamber was proposed. The necessity of heating oxygen and hydrogen and the principle of determining the pressure under which it is advisable to supply oxygen and hydrogen to ensure the maximum intensification of mixing first of oxygen and steam, and then of the formed mixture and hydrogen, were substantiated. Bibl. 20, Fig. 5, Table 3.

Scrutinizing effect of temperature and pressure variation of a double-pressure dual-cycle geothermal power plant turbines on the temperature profile and heat gain of the heat exchangers

In geothermal power plants with dual pressure cycle technology, the optimisation of turbine inlet parameters depending on the pressure and temperature of the geothermal fluid is a very important parameter affecting the production capacity of such plants. In combined systems, where the second stage (low pressure) is fed by the first stage (high pressure), failure to determine the appropriate operating conditions leads to the problem of not achieving optimum performance. In this context, the study aims to develop a methodology for predicting the performance of the system, based on the geothermal water temperatures entering and leaving the heat exchangers, in order to clearly see the effect of the operations carried out within the scope of optimising the turbine inlet parameters on the system behaviour. In this study, EBSILON® Professional software developed by Steag GbmH was utilised to simulate the determined correlations. The effect of the heat exchangers (preheater, evaporator and superheater) in both stage-1 and stage-2 on the temperature profiles and heat gains were determined at 10–17 bar, 126.5–165 °C for Turbine-1 and 4–8 bar, 84–135 °C for Turbine-2. Optimum turbine inlet temperature and pressure have been determined for maximum heat input and exergy efficiency. In this context, each cycle in the Energy Converter System (ECS) was first simulated by changing the turbine input parameters and then thermal analyses of the system were performed using the performance outputs obtained from the simulation software. For turbine-1, it is observed that heat transfer decreases in stage-1 with increasing pressure and temperature, while heat transfer increases in stage-2 fed from stage-1. After 12 bar and 136 °C, the heat transfer of the ECS started to increase and the maximum heat transfer amount was reached at 17 bar and 155 °C. However, it was determined that the exergy efficiency of the ECS started to decrease after 15 bar and 147.6 °C. For turbine-2, it was found that the increase in pressure and temperature decreases the ECS heat transfer but increases the exergy efficiency. As a result of numerous iterations with EBSILON® Professional software, a maximum exergy efficiency of 50.53% was achieved in turbine-1 (15 bar, 147.6 °C) and turbine-2 (8 bar, 114 °C).

Overview of steam turbines and efficiency

Thermal power plants, which produce energy from the burning of fossil fuels that in turn generate turbine-turning steam, contribute a large proportion of energy in the world. Research on how we could apply fluid dynamic and thermodynamic principles in the design of turbines is crucial to improving their efficiency and fuel consumption. This paper mainly aims to explore and summarize how the power efficiency of turbines is maximized in thermal power plants and analyze the designs of turbines that increase proficiency. Literature and past paper review will be the primary method of this research. The main findings of this research are that efficiency in thermal turbines can be increased in three principal ways: a multi-stage expansion mechanism, the application of alternating blades, and in implementation of a reheating system. Using these methods, efficiency has been increased almost a million-fold in steam turbines. The purpose of this paper is to gain insights into how energy output in thermal power plant turbines is maximized and the specific designs of turbines that improve its efficiency.

Isothermal turbines − New challenges. Numerical and experimental investigations into isothermal expansion in turbine power plants

The efficiency of power plants with steam or gas turbines depends on the efficiencies of a thermodynamic cycle and devices implementing this cycle. In the case of high power outputs, we cannot expect a significant increase in the efficiency of individual devices. Therefore, what remains is to increase the efficiency of the implemented thermodynamic cycle − the complex Rankine cycle in the case of steam turbines or the extended Brayton cycle in gas turbine units. The efficiencies of these cycles depend on the hot reservoir temperatures, limited by the materials used. The solution seems to be the thermodynamic cycles with the highest efficiency within given temperature limits, the „generalized Carnot cycles”. About gas turbines, such a cycle is the Ericsson cycle. The most difficult element of this cycle is carrying out high-temperature expansion. So far, there is no literature data on a technical device implementing this process. In this article, we present a method for designing turbine nozzles for isothermal expansion and the results of experimental tests of the first isothermal turbine. In the case of gas microturbines with a regenerator, isothermal expansion can increase efficiency from 24% to 28% up to 36%. An increase in efficiency of several to a dozen percentage points is expected for Organic Rankine Cycle (ORC) turbines. Due to such significant increases in energy generation efficiency, an isothermal turbine may become a future solution for energy systems.

Fractional numerical analysis of γ-Al2O3 nanofluid flows with effective Prandtl number for enhanced heat transfer

Abstract Nanoparticles have gained recognition for significantly improving convective heat transfer efficiency near boundary layer flows. The characteristics of both momentum and thermal boundary layers are significantly influenced by the Prandtl number, which holds a crucial role. In this vein, the current study conducted a detailed computational analysis of the mixed convection flow of $\gamma$Al$_2$O$_3$-H$_2$O and $\gamma$Al$_2$O$_3$-C$_2$H$_6$O$_2$ nanofluids over a stretching surface. This research integrates an effective Prandtl number, utilizing viscosity and thermal conductivity models based on empirical findings. Additionally, a unique double-fractional constitutive model is debuted to accurately evaluate the effective Prandtl number’s function in the boundary layer. The equations were solved using a numerical technique that combined the finite-difference method with the L$_1$ algorithm. This investigation presents numerical findings related to the velocity, temperature distributions, wall shear stress coefficient, and heat transfer coefficient, contrasting scenarios with and without the effective Prandtl number. The research shows that integrating nanoparticles into the base fluids reduces the temperature of the nanofluid with an effective Prandtl number while enhancing the heat transfer rate irrespective of its presence. Nonetheless, the introduction of a fractional parameter reduced the heat transfer efficiency within the system. Notably, the $\gamma$Al$_2$O$_3$-C$_2$H$_6$O$_2$ nanofluid demonstrates superior heat transfer enhancement capabilities compared to its $\gamma$Al$_2$O$_3$-H$_2$O counterpart but also exacerbates the drag coefficient more significantly. Many practical applications of this study include electronics cooling, industrial process heat exchangers, and rotating and stationary gas turbines in power plants, and efficient heat exchangers in aircraft.

Improved creep resistance of Mo-V-Si-B alloys with a density below 8 g/cm³

Improving the efficiency of turbines for power plants and aircraft engines is an increasingly important research subject. Ternary Mo-Si-B alloys, consisting of a molybdenum solid solution (Moss) phase and two intermetallic phases Mo5SiB2 (T2) and Mo3Si, are able to combine balanced room temperature fracture toughness, high temperature creep strength and good oxidation performance. However, the high density (typically > 9 g/cm3) of this class of alloys is a drawback when used as structural materials for rotating components. In this study, high potential Mo-V-Si-B materials which provide a reduced density by about 17 % as compared with the reference alloy Mo-9Si-8B were investigated. A comparative characterization was carried out on sintered (FAST) and arc-melted Mo-40V-9Si-8B alloys. Compressive creep tests reveal competitive creep resistance of this new type of alloys in the application relevant temperature regime.

Investigations of specific modifications in pump as turbine towards performance improvement

ABSTRACT Centrifugal pumps as turbines offer a proven green energy solution for sustainable development, potentially replacing costly custom turbines in micro-hydro power plants and providing cost savings. But the efficiency of the pump as a turbine is lower than that of the dedicatedly designed pump. In this study, new simple modifications are proposed and evaluated on a developed state-of-the-art PAT test rig with impeller of specific speed 43.7 (m-m3/s). Being simple modifications, cost benefits will remain intact without requiring specially designed turbines and trained manpower. New simple modifications in PAT, like balance holes filling, packing seal optimization with appropriate size, leading edge of impeller blade tips modification making it single curve, and inner shroud widening for increasing the width at the inlet of the impeller, were proposed and performed to investigate the influence of the modifications on PAT performance. The experimental study finds that optimal packing seal size and impeller leading edge modifications notably boost PAT efficiency by 3–3.5%, making it worthwhile to implement for resource conservation and performance enhancement. On the other side, inner shroud widening noticed a 1.2% reduction in efficiency, adversely affecting the performance of PAT. Additionally, balance hole filling is neutral and does not have any effect.

Comparative environmental assessment of coated ferritic steels suited to steam turbines of coal-fired supercritical and ultra-supercritical power plants

Coated ferritic steels are the most common materials used for steam turbines construction in coal-fired power plants operating at supercritical and ultra-supercritical conditions of pressure and temperature because of their corrosion and oxidation resistance. However, the environmental implications associated to the steel-coating system have not been fully investigated to choose the best option in terms of sustainability.This work presents three types of ferritic steels as well as three coatings with its corresponding deposition technique, normally used in these environments. The designated materials are P91, P92 and VM12 ferritic steels, while the selected protective coatings are Ni50Cr applied by High-Velocity Oxi Fuel Spray (HVOF), CrN/NbN applied by High Power Impulse Magnetron Sputtering (HiPIMS) and slurry aluminide applied by painting and diffusion heat treatment. Taking these data as a starting point, comparative Life Cycle Assessments (LCA) and economic analysis are performed.This work aims to contribute to better understanding of environmental damages as well as the importance of considering the technical and environmental assessment in the steel-coating selection. The results obtained indicated that the P92 ferritic steel coated with slurry aluminide had the best performance. On the other hand, CrN/NbN coating showed the greater impacts in all the categories studied.

Power plant turbine power trend prediction based on continuous prediction and online oil monitoring data of deep learning

Power output is an important property of steam turbines and more accurate trend prediction is essential for understanding the operation of power plants and anomaly detection in equipment. Equipment power is strongly influenced by human factors and achieving accurate trend prediction is often impossible. In the current research, a continuous prediction model was developed on the basis of deep learning to establish the relationships among oil online monitoring parameters and equipment power. The model used long short term memory (LSTM) method to develop a trend prediction model for oil wear state parameters. Trend prediction results were applied as a test set to establish a deep belief networks (DBN) prediction model for predicting device power. In modeling process, continuous prediction model was optimized via feature selection method on the basis of ridge regression with L2 regularization, recursive feature elimination (RFE) and differential evolution (DE) algorithms for the elimination of subjective factor to decrease cumulative error of forecasting. Comparative experimental results showed that LSTM-RFE-DE-DBN continuous prediction model outperformed LSTM-RFE-DE-BPNN and LSTM-DBN. The developed model realized continuous prediction and applied lubricating oil wear status with objective factors to perform the power prediction of power plant turbines with subjective factors.

Optimization of Dam Operation and Interaction with Groundwater: An Overview Focusing on Greece

The optimization of dam operations to transform them into multi-objective facilities constitutes a challenge for both hydrology, hydrogeology, and hydropower generation. However, the use of the optimal algorithm for such transformation is critically important. Additionally, the literature has highlighted that dams might negatively influence the recharge of groundwater. Within this study, we provide an overview of the available algorithms for the optimization of dam operations. Additionally, an overview focusing on hydropower generation in Greece illustrates the high potential of the Mediterranean region for hydropower generation and the application of MAR. The water quality of the reservoirs is also highlighted as a critical parameter. Within this study, we present indices for water quality monitoring in dam reservoirs, while the most prevailing index is the SRDD. This study constitutes a guide for researchers in choosing the optimal tools for the optimization of dam operations and the water quality monitoring of reservoirs. The present study suggests a meta-heuristic optimization methodology using the harmony search algorithm. The model uses a geometric model of the reservoir and calculates the level–supply curve. Furthermore, a multi-criteria optimization model was developed with two objective functions: the maximum power output from the hydroelectric power plant turbines and the optimal groundwater recharge. The model with appropriate parameter modifications can be applied to any small dam as it is a decision- and policy-making methodology, independent of local conditions. A further step is the application of these approaches dealing with field data and the numerical modeling of case studies. The interdisciplinary approach of this study links deferent aspect and scientific perceptions, providing a comprehensive guide to optimal water resource management and environmental sustainability.

Study of the Motion Performance of Marine Current Power Plant Turbine Floaters Due To Ocean Current Forces under Moored Conditions

Indonesia targets carbon emissions to reach 0% in 2060 and is replaced by optimizing the use of renewable energy sources. Indonesia as an archipelago country, with the potential of thousands of straits can be utilized as a source of ocean currents as a source of electrical energy. The electricity generated is obtained from a turbine rotor that rotates due to the force of the ocean current flow. To support the turbine rotor to move in the sea, a floating support structure is needed. In this study, a trimaran tipe support structure is used where on the left and right sides are installed 2 (pieces) turbine rotors @ 50 kW each, so that the total has a capability of 200 kW (@4 x 50 kW). The novelty of this study is the utilization of Trimaran technology in marine current power generation turbines, which has good stability, low resistance, and a wider deck area rather than monohull structures. A numerical study using Computational Fluid Dynamics (CFD) is used to calculate the program. The results showed that the floater only moves backward and then is pulled forward with a small amplitude of movement in the X-direction, while those on the Y and Z axes are insignificant. The turbine floater can be immediately stabilized and the turbine rotor will rotate due to the force of the ocean current received. Therefore, in this study, the marine current turbine using trimaran type is showing good ability to survive in Indonesian waters even in high current areas.

Reliable non-destructive detection and characterization of material degradation caused by high-temperature corrosion

Components made from nickel-based superalloys are widely used in gas turbines for aircraft and power plants. In addition to high corrosion resistance, they feature very good creep and fatigue strength at temperatures near 1000 °C. Yet, corrosive attack can significantly reduce the mechanical properties, and thus the expected remaining service life of these components. Therefore, in the case of safety-critical parts, detailed information on the component’s actual condition is crucial. In the present study, a non-destructive electromagnetic testing technique was developed that is capable of reliably detecting early degradation caused by high-temperature corrosion on components made of nickel-based alloys. The testing technique combines the use of temperature-resistant sensors and a variation of the component temperature in a wide range. This allows the determination of the magnetic properties of the component as a function of temperature. It was shown that the measurement signals obtained correlates with the degree of chromium depletion. Thus, a reliable and non-destructive detection of degradation caused by high-temperature corrosion was possible. A special feature of the presented testing technique is that degradation can be detected at an earlier stage compared to conventional methods. In addition, the technique enables the characterization of the microstructure condition directly in the component. The applicability of the testing technique was demonstrated for components with concave surface geometries, like turbine blades.

Research and development of a gravitational water vortex micro-HPP in the conditions of Kyrgyzstan

The field of research in this article is small-capacity hydropower conversion plants. The object of the study is the turbines of low-pressure micro hydro power plants ( micro HPP) that convert the energy of velocity head into electrical energy. The purpose of the study is to study the features of the operation of rotary turbines and determine the dependence of the rotational speed on the load and efficiency. The influence of the central gap in the turbine blades on its efficiency was also evaluated. During the research, the results of three-dimensional modeling of three types of hydraulic turbines using the Kompasflow software product and the results of experimental studies obtained on a specially created hydraulic stand were used. Based on the results obtained, it was found that, regardless of the types of turbines under consideration, the rotational speed decreases with increasing load, and there is a certain load interval at which the maximum efficiency is achieved. The presence of a central gap in the turbine blades does not lead to a significant increase in the efficiency of the turbine.