scholarly journals Assessment of operational reliability indicators of pit rope-operated excavators

2020 ◽  
Vol 6 (4) ◽  
pp. 25-44
Author(s):  
Vladimir V. Moskvichev ◽  
Maksim A. Kovalev
Keyword(s):  
Coal Mine ◽  
Operational Reliability ◽  
Current Level ◽  
Operating Conditions ◽  
Reliability Indicators

The results of the study of operation reliability indicators of rope-operated excavators for 20172019 in the conditions of the Kolyvansky coal mine of Siberian Anthracite JSC are presented. The analysis of changes in reliability indicators of the main groups of equipment is performed. The conclusion is made about the current level of reliability for the main groups of excavator equipment and the components of the equipment that require increasing operational reliability are identified. The rating of reliability among rope-operated excavators used in the conditions of the Kolyvansky coal mine has been compiled. Recommendations have been developed to maintain and improve the reliability of the main groups of equipment and they components for rope-operated excavators in operating conditions at the Kolyvansky coal mine.

scholarly journals Assessment of Operational Reliability Indicators of Mine Hydraulic Excavators

2020 ◽  
pp. 745-756
Author(s):  
Vladimir V. Moskvichev ◽  
Maksim A. Kovalev
Keyword(s):  
Coal Mine ◽  
Random Variables ◽  
Operational Reliability ◽  
Main Equipment ◽  
Reliability Indicators ◽  
Hydraulic Excavators

The results of the reliability indicators study of mine hydraulic excavators in the coal mine «Kolyvansky» of JSC «Siberian Anthracite» are presented. The analysis of the reliability indicators changes of the main equipment assemblies and excavators in general is performed. Quantitative values of the random variables have been determined, and the effectiveness of the existing system for collecting and analyzing information about the excavators reliability has been assessed. The rating of reliable hydraulic excavators in the coal mine «Kolyvansky» has been compiled

scholarly journals Reliability of water fittings in operating conditions

2021 ◽  
Vol 263 ◽  
pp. 04010
Author(s):  
Alexander Svintsov ◽  
Evgeniy Alekseev ◽  
Svetlana Shambina ◽  
Roman Fediuk ◽  
Vladislav Fominov
Keyword(s):  
Water Supply ◽  
Residential Buildings ◽  
Operational Reliability ◽  
Probability Of Failure ◽  
Technical Condition ◽  
Supply System ◽  
Operating Conditions ◽  
Random Coincidence ◽  
Reliability Indicators ◽  
Residential Neighborhood

Water fittings are an integral part of the internal water supply system. The reliability of their work under operating conditions largely influence on the continuity of water supply to the population. The reliability indicators of sanitary fittings allow the services responsible for the technical condition of the indoor water supply of houses to pay priority attention to the factors that determine the uninterrupted water supply of the population and reduce the loss of drinking water. In this study, the results of indicators of operational reliability of faucets for sinks in kitchens and washbasins in toilet rooms of apartments of multi-store residential buildings in a residential neighborhood are presented. The study was performed based on the analysis of records in the logs of data on valve failures for 2016-2018. The main malfunctions are established, the random coincidence of which leads to failures. The reliability of sanitary fittings is affected not only by their structure and the characteristics of the materials, as well as by the exploitation conditions. The probability of failure-free operation of sanitary fittings in exploitation conditions for a time not exceeding the duration of the reduction of water supply to consumers in residential buildings is the basic parameter of its reliability.

scholarly journals Prognostics-based adaptive control strategy for lifetime control of wind turbines

2021 ◽  
Author(s):  
Edwin Kipchirchir ◽  
Manh Hung Do ◽  
Jackson Githu Njiri ◽  
Dirk Söffker
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Control Strategy ◽  
Fatigue Loading ◽  
Operational Reliability ◽  
Operating Conditions ◽  
Rotor Blades ◽  
Time Step ◽  
Damage Level ◽  
Structural Loading

Abstract. Variability of wind profiles in both space and time is responsible for fatigue loading in wind turbine components. Advanced control methods for mitigating structural loading in these components have been proposed in previous works. These also incorporate other objectives like speed and power regulation for above-rated wind speed operation. In recent years, lifetime control and extension strategies have been proposed to guaranty power supply and operational reliability of wind turbines. These control strategies typically rely on a fatigue load evaluation criteria to determine the consumed lifetime of these components, subsequently varying the control set-point to guaranty a desired lifetime of the components. Most of these methods focus on controlling the lifetime of specific structural components of a wind turbine, typically the rotor blade or tower. Additionally, controllers are often designed to be valid about specific operating points, hence exhibit deteriorating performance in varying operating conditions. Therefore, they are not able to guaranty a desired lifetime in varying wind conditions. In this paper an adaptive lifetime control strategy is proposed for controlled ageing of rotor blades to guaranty a desired lifetime, while considering damage accumulation level in the tower. The method relies on an online structural health monitoring system to vary the lifetime controller gains based on a State of Health (SoH) measure by considering the desired lifetime at every time-step. For demonstration, a 1.5 MW National Renewable Energy Laboratory (NREL) reference wind turbine is used. The proposed adaptive lifetime controller regulates structural loading in the rotor blades to guaranty a predefined damage level at the desired lifetime without sacrificing on the speed regulation performance of the wind turbine. Additionally, significant reduction in the tower fatigue damage is observed.

scholarly journals Reliability of the RBMK-1000 coolant flow measurement system

2019 ◽  
Vol 5 (1) ◽  
pp. 81-87
Author(s):  
Arkady I. Pereguda
Keyword(s):  
Mathematical Model ◽  
Measurement System ◽  
Flow Measurement ◽  
Rotation Period ◽  
Operation Time ◽  
Operational Reliability ◽  
Coolant Flow ◽  
Reliability Indicators ◽  
Parametric Reliability ◽  
Two Parameters

An analysis of statistical data of diagnostic measurements of two parameters determining the performance of the RBMK-1000 SHADR-8A flowmeters – the minimum value of the negative amplitude half-wave at the transistor flow measuring unit (TIBR) input and the mean-square deviation over the flowmeter ball rotation period – made it possible to develop a mathematical model of the flowmeter parametric reliability. This mathematical model is a random process, which is a superposition of two delayed renewal processes. Studying the flowmeter operational reliability model provides an exponential estimate of the probability that the parameters determining the flowmeter performance will not exceed the specified levels. Using the Bernoulli scheme and the probability-estimating relationship for the flowmeter performance parameters, it is possible to calculate the probability of failure-free operation of both a single reactor quadrant and the coolant flow measurement system. In addition, it becomes possible to estimate the quadrant failure rate. Important for practice is the possibility of predicting the number of failed flowmeters depending on the system operation time. An indicator of the system reliability can be the average number of failed flowmeters, the relation for which is given in the paper. All the research results were obtained without any additional assumptions about the random values distribution laws. The obtained results can be easily generalized for the cases when the vector dimension of the determining parameters is greater than two. The use of the results of this study is illustrated by calculated quantitative values of the flowmeter parametric reliability indicators and the coolant flow measurement system.

scholarly journals Pressure losses and oscillations in a compact valve of a steam turbine

2021 ◽  
Vol 345 ◽  
pp. 00027
Author(s):  
Václav Sláma ◽  
David Šimurda ◽  
Lukáš Mrózek ◽  
Ladislav Tajč ◽  
Jindřich Hála ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Pressure Oscillation ◽  
Operational Reliability ◽  
Operating Conditions ◽  
Steam Turbines ◽  
Valve Seat ◽  
Pressure Losses ◽  
Oscillation Analysis ◽  
Seat Angle ◽  
Wide Range

Characteristics of a new compact valve design for steam turbines are analysed by measuring pressure losses and oscillations on the valve model. It is the model of an intercept valve of the intermediate-pressure turbine part. This valve is relatively smaller hence cheaper than usual control and intercept valves. Besides, four different valve seat angles were tested in order to investigate the valve seat angle influence. In order to further clarify measured phenomena, the wide range of numerical simulations were also carried out. Measurements were performed in the Aerodynamic laboratory of the Institute of Thermomechanics of the Czech Academy of Sciences in an air test rig installed in a modular aerodynamic tunnel. Numerical simulations were performed in the Doosan Skoda Power Company using a package of ANSYS software tools. Measurement results are compared with numerical and generalized in the form of valve characteristics and pressure oscillation maps. As a result of the pressure loss analysis, pressure losses in similar valve assemblies can be predicted with required accuracy for each new turbine where modern compact valves are used. As a result of the pressure oscillation analysis, operating conditions at which dangerous flow instabilities can occur were identified. Thanks to this, the areas of safe and dangerous operating conditions can be predicted so that the operational reliability of the valve can be guaranteed.

Experimental and Numerical Study on Pressure Losses and Flow Fluctuations in a High-Pressure Valve Assembly of Steam Turbine Governing System

2020 ◽  
Author(s):  
Vaclav Slama ◽  
Lukas Mrozek ◽  
Bartolomej Rudas ◽  
David Simurda ◽  
Jindrich Hala ◽  
...  
Keyword(s):  
High Pressure ◽  
Flow Field ◽  
Numerical Simulations ◽  
Pressure Loss ◽  
Operational Reliability ◽  
Operating Conditions ◽  
The Real ◽  
Pressure Losses ◽  
Flow Fluctuations ◽  
Valve Assembly

Abstract Aerodynamic measurements and numerical simulations carried out on a model of a high-pressure valve assembly used for nozzle governing of a turbine with 135MW output are described in this paper. Aim of the study is to investigate effects of control valve’s strainers on pressure losses and unsteadiness in the flow field. It is an important task since undesirable flow fluctuations can lead to operational reliability issues. Measurements were carried out in the Aerodynamic laboratory of the Institute of Thermomechanics of the Czech Academy of Sciences (IT) where an aerodynamic tunnel is installed. Numerical simulations were carried out in the Doosan Skoda Power (DSP) Company using ANSYS software tools. The experimental model consists of one of two identical parts of the real valve assembly. It means it consists of an inlet pipeline, a stop valve, a valve chamber with two independent control valves, its diffusers and outlet pipelines. The numerical model consists of both assembly parts and includes also an A-wheel control stage in order to simulate the real turbine operating points. The different lifts of the main cone in each control valve for its useful combinations were investigated. Results were evaluated on the model with control valve’s strainers, which were historically used in order to stabilize the flow, and without them. The results of the experimental measurement were compared with the numerical results in the form of pressure losses prediction. From measured pressure fluctuations, it was found out where and for which conditions a danger of flow instabilities occurs. It can be concluded that there is a border, in terms of operating conditions, where the flow field starts to be unstable and this border is different dependent of the fact whether the control valve’s strainers are used or not. Therefore, the areas of safe and danger operational reliability can be predicted. The influence of the control valve’s strainers on the maximal amplitude of periodic fluctuations appears only for the cases when valves are highly overloaded. For normal operating conditions, there is no difference. As a result, the control valve’s strainers do not have to be used in standard applications of valve assemblies. Furthermore, a loss model for valve pressure loss estimation could be updated. Therefore, a pressure loss should be predicted with a sufficient accuracy for each new turbine bid with similar valve assemblies.

scholarly journals Improving of the quality and reliability of water supply systems on the basis of modern information and computing technologies

2018 ◽  
Vol 39 ◽  
pp. 04003 ◽  
Author(s):  
Aleksandr V. Alekseev
Keyword(s):  
Water Supply ◽  
Operational Reliability ◽  
Operating Conditions ◽  
Mode Analysis ◽  
Water Supply Systems ◽  
Common Information ◽  
Quality Of Water ◽  
Common Information Space ◽  
Hydraulic Conditions ◽  
Supply Systems

The article deals with the issues of increasing the reliability and quality of water supply systems operation on the basis of modern methods and software complexes for the analysis and development of hydraulic conditions. Against the backdrop of the analysis of the literature on the problem of reliability, the relevance and insufficiency of attention to maintaining the required level of reliability at the stage of water supply systems operation are revealed. The main factors that affect on operational reliability are considered. These factors are largely associated with the competent organization of operating conditions of water supply systems. A brief description of the «Angara-WS» computer program for solving the problems of analyzing and developing of hydraulic conditions, as well as the experience of its practical application, is given. A special feature of this complex is its universality, the possibility of multilevel representation of models, the execution of one-and multi-level calculations, integration into a common information space of the enterprise, automation of the processes of mode analysis, accumulation and analysis of damage statistics.

scholarly journals Evaluation of the Thermal Stability and Surface Characteristics of Thermoplastic Polyurethane V-Belt

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1502 ◽  
Author(s):  
Piotr Krawiec ◽  
Leszek Różański ◽  
Dorota Czarnecka-Komorowska ◽  
Łukasz Warguła
Keyword(s):  
Surface Morphology ◽  
Thermoplastic Polyurethane ◽  
Surface Characteristics ◽  
Operational Reliability ◽  
Operating Conditions ◽  
Hardness Tests ◽  
Diagnostic Characteristics ◽  
Braking Torque ◽  
Torque Load ◽  
Belt Transmission

This article proposes thermography as a non-contact diagnostic tool for assessing drive reliability. The application of this technique during the operation of the belt transmission with a heat-welded thermoplastic polyurethane V-belt was presented. The V-belt temperature changes depending on the braking torque load at different values of the rotational speed of the active pulley, which were adopted as diagnostic characteristics. In this paper, the surface morphology of the polyurethane (PU) belts was assessed on the basis of microscopic and hardness tests. A surface roughness tester was used to evaluate the surface wear. The surface morphology and topography of the materials was determined by scanning electron microscopy (SEM) and optical microscopy. It was found that the most favorable operating conditions occurred when the temperature values of active and passive connectors were similar and the temperature difference between them was small. The mechanical and structure results indicate that the wear of the PU belt was slight, which provided stability and operational reliability for V-belt transmission. The microscopic images lacked clear traces of cracks and scratches on the surface, which was confirmed by the SEM observations.

Vibration Based Condition Monitoring of Helicopter Gearboxes Based on Cyclostationary Analysis

2019 ◽  
Author(s):  
Alexandre Mauricio ◽  
Linghao Zhou ◽  
David Mba ◽  
Konstantinos Gryllias
Keyword(s):  
Experimental Tests ◽  
Operational Reliability ◽  
Health Condition ◽  
Operating Conditions ◽  
False Alarms ◽  
Complex Structures ◽  
Planetary Gearbox ◽  
Bearing Defects ◽  
Envelope Spectrum ◽  
Selection Of

Abstract The core of a helicopter drivetrain is a complex planetary main gearbox (MGB) which reduces the high input speed generated by the engines in order to provide the appropriate torque to the main rotors and to other auxiliary systems. The gearbox consists of various shafts, planetary gears and bearings and operates under varying conditions under excessive friction, heat and high mechanical forces. The components are vulnerable to fatigue defects and therefore Health and Usage Monitoring Systems (HUMS) have been developed in order to monitor the health condition of the gearbox, focusing towards early, accurate and on time fault detection with limited false alarms and missed detections. The main aim of a HUM System is by health monitoring to enhance the helicopters’ operational reliability, to support the maintenance decision making, and to reduce the overall maintenance costs. The importance and the need for more advanced and accurate HUMS have been emphasized recently by the post-accident analysis of the helicopter LN-OJF, which crashed in Norway in 2016. During the last few decades various methodologies and diagnostic indicators/features have been proposed for the monitoring of rotating machinery operating under steady conditions but still there is no global solution for complex structures. A new tool called IESFOgram has been recently proposed by the authors, based on Cyclostationary Analysis, focusing on the accurate selection of a filtering band, under steady and varying speed conditions. Moreover the Cyclic Spectral Coherence is integrated along the selected frequency band leading to an Improved Envelope Spectrum. In this paper the performance of the tool is tested on a complex planetary gearbox, with several vibration sources. The method is tested, evaluated and compared to state of the art methods on a dataset captured during experimental tests under various operating conditions on a Category A Super Puma SA330 main planetary gearbox, presenting seeded bearing defects of different sizes.

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