Primary Equipment Research Articles

Experimental study on hydraulic performance and cavitation characteristics of a R134a refrigerant self-lubricating centrifugal pump

As the primary power equipment in pump flooding cooling systems, the efficiency and performance of mechanical pumps play a crucial role in two-phase cooling systems. A high-speed centrifugal pump with self-lubricating working fluid was designed with a speed of 7500 rpm and a flow coefficient of 0.0506. The hydraulic and cavitation performance of the pump were tested with R134a as the working fluid. The results show that the working fluid pump is capable of efficiently pumping R134a with an efficiency of 40.3% and a head coefficient of 0.988 under the design condition. Within the tested range of inlet temperature from 5°C to 15°C, the flow coefficient from 0.01 to 0.105, and the height of the refrigerant tank from 1.4 m to 5 m, lower net positive suction heads available at the same flow rate will reduce the pump head, increase power consumption, and decrease efficiency. Increasing the pump speed from 3000 rpm to 7500 rpm can improve the pump's performance. At 6000 rpm, the critical cavitation number of the working fluid pump increases with the increase in flow coefficient. At 7500 rpm, the critical cavitation number has a minimum value when the flow coefficient φ = 0.0434. At the design speed and flow rate, both the critical cavitation coefficient and fracture cavitation number increase as the inlet temperature decreases. The inducer can significantly reduce the critical cavitation number of the pump. Finally, an empirical correlation considering the thermodynamic effects is proposed to predict the increase in the critical cavitation number.

Assessment of Bitumen Paver and HMP Efficiency for a Road Project

One of the important and dependable sectors of the national economy is the equipment used in highway construction. In the process of building constructions, efficient utilization of labour, supplies, and machinery must be fervently pursued through competent project management. The adoption of innovative procedures and new equipment has resulted in a dramatic advance in construction technology in recent decades. The selection of the right type and size of construction equipment typically affects how productive a project is on the job site. Thus, it is essential that site managers and construction planners understand the primary equipment categories that are most frequently used in construction. Technical aspects and working conditions are taken into consideration in the article's method of calculating the operational productivity and cost of asphalt pavers. This increases the accuracy of decisions made about how to organize and manage highway maintenance activities on Chikhali-Tarsod NH-6.

Optimized Wavelet Transform for the Development of an Algorithm Designed for the Analysis of Digital Substation Electrical Equipment Parameters

This study emphasizes the urgent need for systems that monitor the operational states of primary electrical equipment, particularly power transformers. The rapid digitalization of and increasing data volumes from substations, coupled with the inability to retrofit outdated equipment with modern sensors, underscore the necessity for algorithms that analyze the operational parameters of digital substations based on key power system metrics such as current and voltage. This research focuses on digital substations with Architecture III and aims to develop an algorithm for processing digital substation data through an appropriate mathematical tool for time-series analysis. For this purpose, the fast discrete wavelet transform was chosen as the most suitable method. Within the framework of the research, possible transformer faults were divided into two categories by the nature of their manifestation. A mathematical model for two internal transformer fault categories was built. The most effective parameters from the point of view of the possibility of identifying an internal fault were selected. The proposed algorithm shows its effectiveness in the compact representation of the signal and compression of the time series of the parameter to be monitored.

Enhanced path tracking control of hydraulic support pushing mechanism via adaptive sliding mode technique in coal mine backfill operations

The hydraulic support pushing mechanism is the primary equipment utilized in coal mine backfill operations, playing a crucial role in enhancing filling efficiency, ensuring a stable filling body, and managing gob safety. This paper focuses on analyzing the dynamic model and the interrelationship of the hydraulic cylinder, which serves as the power source for the pushing mechanism. To address the intricate coupling effects arising from the hydraulic cylinders and the displacement-force induced by the shared pump, this study employs feedforward compensation for decoupling analysis. Additionally, this article introduces an adaptive sliding mode approach law and an adaptive synovial controller to combat issues such as buffeting and interference. The simulation results demonstrate that the sliding mode reaching law proposed in this paper can achieve a stable state in approximately 3 seconds, which is significantly better than other methods. Combining the experimental equipment information from a mining area in Hebei Province with Amesim-Simulink simulation results, it is evident that the adaptive sliding mode controller exhibits an error range between approximately 1.33E-4 and 1.5E-4 during the stable phase. This performance surpasses traditional PI and fuzzy PID controllers in terms of path tracking ability, effectively enabling precise control of the filling support pushing mechanism.

Study on Laser Transmission Welding Technology of TC4 Titanium Alloy and High-Borosilicate Glass.

As the demand for high-performance dissimilar material joining continues to increase in fields such as aerospace, biomedical engineering, and electronics, the welding technology of dissimilar materials has become a focus of research. However, due to the differences in material properties, particularly in the welding between metals and non-metals, numerous challenges arise. The formation and quality of the weld seam are strongly influenced by laser process parameters. In this study, successful welding of high-borosilicate glass to a TC4 titanium alloy, which was treated with high-temperature oxidation, was achieved using a millisecond pulsed laser. A series of process parameter comparison experiments were designed, and the laser welding behavior of the titanium alloy and glass under different process parameters was investigated using scanning electron microscopy (SEM) and a universal testing machine as the primary analysis and testing equipment. The results revealed that changes in process parameters significantly affect the energy input and accumulation during the welding process. The maximum joint strength of 60.67 N was obtained at a laser power of 180 W, a welding speed of 3 mm/s, a defocus distance of 0 mm, and a frequency of 10 Hz. Under the action of the laser, the two materials mixed and penetrated into the molten pool, thus achieving a connection. A phase, Ti5Si3, was detected at the fracture site, indicating that both mechanical bonding and chemical bonding reactions occurred between the high-borosilicate glass and the TC4 titanium alloy during the laser welding process.

Electrophysical Characteristics of Cast Polymer Materials for Internal Electrical Insulation Structures of Primary Power Equipment

Electrophysical Characteristics of Cast Polymer Materials for Internal Electrical Insulation Structures of Primary Power Equipment

Applying Microsoft Power Platform to Improve Primary Medical Equipment Maintenance Processes.

Post-COVID, our hospital shifted to online systems using Microsoft Power Platform to mitigate errors and delays. SharePoint and Power Apps manage equipment maintenance records and submissions, enhancing immediacy and transparency. Power Automate automates report generation and reminders, improving task completion rates. Power BI visualizes data for streamlined management. Adjustments to real-time reporting enhanced efficiency, reducing manual efforts and improving completion rates.

Data Center Air-cooled Chiller Broadband and Tonal Noise Control

Data centers require vast amounts of cooling using large farms of air-cooled chillers as the primary equipment of choice. The amount and nature of noise generated by these chiller farms to the surrounding area can create complaints and the noise control solutions require an understanding and knowledge of both broadband and tonal noise. The dominant noise sources on air-cooled chillers are compressors and condenser fans, each of which produce both broadband and tonal noise spectrums. Therefore, noise control solutions should address both the broadband and tonal aspects of the source. A common noise control solution for chillers serving data centers is a sound barrier wall and while effective at providing overall broadband noise control, does little in targeting tonal issues. However, a sound barrier wall can be supplemented to address these tonal issues by applying source treatments to the chiller, such as a sound cover treatment for the compressors and associated refrigerant piping and sound stacks and intakes for the condenser fans. In addition, barrier walls an create a "pit" application impeding chiller condenser fan discharge air resulting in recirulation and nuisance trips. Using a sound stack source treatment with a barrier wall can help mitigate this issue while providing attenuation.

Проектирование современных российских дробильно-перегрузочных установок для комплексов циклично-поточной технологии

The article discusses methodological aspects of designing semi-stationary and mobile crushing and transfer units (DPU) carried out by the experts of Uralmashzavod PJSC and IGD Ural Branch of the Russian Academy of Sciences on behalf of the Russian Metalloinvest company during the development of the Russian DPU-7200 model. As the result of the R&D work performed, a DPU was manufactured and installed at a mining operation as part of the in-pit crushing and conveyor (IPCC) systems, which is intended for conveyor transportation of ore from the open pit. A distinctive feature of the discussed DPU is that it is made as a complete system with the supporting steel structures integrated in its design, which makes it possible to relocate it during the service life when expanding the IPCC. The issues concerned with justifying the DPU layout, parameters of the receiving and unloading hoppers are discussed with account of structural, strength, mining and technological factors. The paper presents the technical characteristics of the developed DPU, as well as the design features of the primary equipment. The impact of the related technological factors, i.e. irregular character of dump truck traffic, the technological and temporal modes of the IPCC operation in general and those of the DPU in particular, the designed schedule of maintenance and repair, etc., is shown.

Study on Breakdown Characteristics and Attenuation Characteristics of Air Mixed Gas

Abstract Nowadays, the global demand for environmental protection and energy saving is getting higher and higher. In the past, SF6 gas was regarded as an environmentally unfriendly gas in the circuit breaker with SF6 gas as the insulating medium. In order to save energy and reduce emissions, this paper uses clean and environmentally friendly air as the arc extinguishing medium. The gas mixture studied contains N2, O2 and CO2. Through two approximate values of Boltzmann equation, we obtain the electron energy distribution function of air mixed gas under different electric field reduction conditions. By studying the changes of ionization and adsorption coefficients of particles under various collision conditions, we obtained the conversion breakdown field strength (E/N) Cr of air mixture. An arc attenuation model is built to characterize the arc attenuation characteristics using the prior transport characteristics as input. The arc attenuation process is broken down into three steps: heat recovery, pre-ignition, and arcing. All of these phases are determined by the changes in axial temperature and arc conductance over time. Analysis is done on the air and nitrogen thermal recovery and pre-dielectric recovery phases. This study explores the use of clean dielectrics to ensure optimum performance of primary equipment in the power system, based on current circumstances.

Digital Twin Modeling for Hydropower System Based on Radio Frequency Identification Data Collection

The safe and steady operation of hydropower generation systems is crucial for electricity output in the grid. However, hydropower stations have complicated interior structures, making defect detection difficult without disassembly inspections. The application of digital modeling to hydropower stations will effectively promote the intelligent transformation of hydropower stations as well as reduce the maintenance costs of the system. This study provides a model of the power generating and transmission system for hydropower plants, with an emphasis on primary equipment and measured data. The model utilizes PSCAD to digitalize state response in hydropower plants with various short-circuit faults. The fault information is identified and learned using the Adaptive Time–Frequency Memory (AD-TFM) deep learning model. It is demonstrated that our proposed method can effectively obtain the fault information through radio frequency identification (RFID). The accuracy of the traditional method is 0.90, while the results for AD-TFM show a fault classification accuracy of 0.92, which is more than enough to identify multiple fault types compared to the existing methods.

Postmortem analysis of MgO–C bricks used in smelting furnace for fabricating TiC-bearing slag

The process of “high temperature carbonization and low temperature chlorination”, considered as one of the most promising technologies, can extract over 60% titanium from blast furnace slag containing TiO2 at a concentration of 20%–25%. The primary equipment for high temperature carbonization is an electric furnace lined with MgO–C bricks. In this study, post-mortem analysis was conducted to investigate the corrosion and failure mechanisms of MgO–C refractory bricks taken from different areas of a circular electric furnace after 1200 cycles of service. Through XRD, SEM-EDS, and thermodynamic calculation analysis, the reaction and corrosion mechanism between MgO–C bricks and the slag were analyzed. The results demonstrated that the gradual corrosion of the brick was primarily attributed to the alternating effects of carbon oxidation and MgO dissolution. Moreover, an increase in temperature led to a higher corrosion rate of the refractories. At temperatures exceeding 1560 °C, the pre-formed barrier layer composed of MgAl2O4 and MgTi2O4 melted into the slag. And as TiO2 content decreased and TiC content increased, there was a gradual decline in the erosive impact of the slag. Furthermore, the failure mechanisms of refractory bricks in different areas varied due to the distinctive structure of the electric furnace. The bricks at the slag line area were mainly destroyed by slag corrosion, oxidation and thermal shock spalling, which had the shortest service life.

Problematika Sarana dan Prasarana dalam Proses Belajar Mengajar di SD Negeri 104202 Bandar Setia

Currently, Indonesian education faces several challenges in its efforts to achieve global competitiveness in various fields. Various efforts have been made to improve education standards, including expanding educational opportunities in various fields, such as through improving facilities and infrastructure. Education management, simply called learning management, is a tool to help students achieve learning goals. Several methods are used in education management, including organizing, planning, directing, and forming relationships in the field of education. In this publication, we mainly discuss the state of infrastructure quality that is still lacking in order to facilitate the learning process in schools. The literature study method is the technique used in this qualitative research project. In order to collect information for this research, comprehensive observations and interviews were carried out at SD Negeri 104202 Bandar Setia. The data collected resulted in a gap in the quality of primary and secondary school equipment.

Dimensional Analysis based Prediction Model for Fuel Consumption in the Deutz Agrotrac Tractor

Background: Fuel consumption is a critical factor in the performance of an agricultural tractor. And it can be affected by numerous parameters. Farming practices is an essential aspect that affects the cost of operation and the overall efficiency of the tractor. Predictions of fuel consumption rates in tractors and the energy consumption parameters of primary tillage equipment under local conditions are therefore essential selection criteria in purchasing decisions. Methods: A prediction model for fuel usage during tillage operations was created using dimensional analysis. The model was established by incorporating experimental findings into an equation. The experiment was conducted in the El Ouracia region of Setif, Algeria in 2022/2023 crop season, with fuel usage per time unit determined through topping-up the tank method. The fuel experiment parameters were measured according to their respective standard procedures. Result: By simulating fuel usage with tillage depth, tillage width, travel speed, soil bulk density and cone index. The constant in the prediction model was obtained. This developed model has the potential to forecast the tractor fuel consumption during tillage operation.

The SPARC cryogenic system

The SPARC project at Commonwealth Fusion Systems (CFS) is a tokamak system designed to demonstrate commercially relevant fusion energy and achieve net fusion power output during the first operating campaign, with eventual fusion pulse energies exceeding 1 GJ. The SPARC tokamak includes eight magnet systems, three that use high-temperature superconducting (HTS) tapes. The SPARC cryogenic system (CRYO) consists of three supercritical helium cryogenic loops at nominal temperatures of 8 K, 15 K, and 80 K. CRYO 8 K and 15 K loops cool the HTS magnets to maintain thermal stability and prevent quench, while magnets cooled to 80 K are normally conductive. CRYO provides cold helium using a hybrid system that includes a Brayton-cycle-based cryoplant supporting all CRYO temperature loops, and a fixed volume 8 K blowdown system to remove heat and maintain temperature stability of the toroidal field (TF) magnets during and immediately following fusion pulses. CRYO 4.5 K equivalent peak cooling power is 17 kW for the cryoplant and 2.9 MW for the blowdown system during a 10-second fusion pulse. Primary cryoplant mechanical equipment includes screw compressors, turbo-expanders, heat exchangers, and circulation pumps, while the blowdown system consists of a series of warm and cold helium storage tanks operating at independent temperatures and pressures, with make-up compressors to reset the blowdown system between pulses. CRYO also includes a distribution valve box and multiple vacuum-jacketed (VJ) process lines ranging in nominal diameter from 20 to 600 mm. This paper investigates the various sub-elements which in combination represent SPARC CRYO, and attempts to address some of the technical challenges identified by the team.

Application of Modern Approaches to the Numerical Modeling of the Stress-Strain State for the Strength Assessment of Complex Units of the NPP Primary Circuit Equipment. Part 3. Application of Submodeling Technique and Extended Finite Element Method for Calculation of the Reactor Pressure Vessel Nozzle Zone

Application of Modern Approaches to the Numerical Modeling of the Stress-Strain State for the Strength Assessment of Complex Units of the NPP Primary Circuit Equipment. Part 3. Application of Submodeling Technique and Extended Finite Element Method for Calculation of the Reactor Pressure Vessel Nozzle Zone

Study on the error characteristics of transformer for primary and secondary fusion used in pole-mounted switchgear

The fusion of primary and secondary functions refers to integrating the function of primary equipment and secondary equipment together. If doing so, the working condition of the equipment for primary and secondary fusion becomes more and more complex and bad, especially the transformer working in the smaller workspace after fusing. Therefore, this paper focuses on the transformer used in primary and secondary fusion pole-mounted Switchgear and establishes the temperature field and electric field simulation model of the primary and secondary fusion pole-mounted switchgear transformer, respectively, and the temperature rise and the environment electric field interference influencing the error of transformer are analyzed as well. When the working environment temperature ranges from -40 to 70°C, the maximum error of low-power current transformers and resistive voltage transformers is 0.1246% and 0.0371%, respectively. The electric field is one of the main factors influencing resistive voltage transformers, which makes ratio errors and angle errors -0.256% and -22.5392’, respectively. The research reveals that under conditions, the error is mainly dependent on temperature rise and electric field. These two factors have a great influence on the error, while the transformers still have enough reliability.

Разработка и исследование подхода к обработке сигналов цифровых измерительных трансформаторов тока и напряжения

During the development of secondary systems of stations and substations, including relay protection, automation, control, electricity metering, etc., qualitative changes have recently occurred due to the introduction of digital technologies. The introduction of digital technologies is supported by innovative development programs such as “Digital Transformation 2030”. The introduction of digital technologies is associated with the use of digital data transmission channels according to uniform standards. Projects of “digital substations” are being actively implemented with the transmission of digital information at all levels, including the primary equipment, the transmission of information both from current and voltage measuring transformers, and from switching devices. Currently, digital instrument transformers are actively being developed and implemented, in which information about measured currents and voltages is presented in digital code. New approaches to measure primary currents and voltages, and transmit information pose new challenges, and open prospects for improving signal processing methods used for relay protection purposes. Thus, the relevant aim of the study is the development and research of approaches to digital processing of signals of digital instrument current and voltage transformers. To solve the problems posed within the framework of this study, analytical and numerical solution methods have been used. Numerical methods are applied using software products such as MathCAD and the Python programming language to generate signals and display them on graphs. To substantiate the reliability, verification of the results obtained by different methods is carried out. The authors have formulated an approach to digital processing of signals obtained using current sensors of a digital instrument transformer. The authors have studied the approach to determine synchronized current vector values by processing information received from primary current converters. The characteristics of the algorithm for obtaining a vector have been analyzed and the dependences of errors on the influence of distorting factors have been plotted. The proposed approach is a development of the existing approach to obtain a vector by getting information from current sensors operating on different physical principles. The results show the advantages of the proposed method. The proposed digital signal processing algorithm is more technically expensive since it contains at least two metrologically calibrated measuring channels instead of one. However, all other things being equal, it allows to increase the accuracy and speed of the digital processing algorithms taken as a prototype. The results obtained can be used to formulate algorithms for measuring relay protection devices.

Evaluation of overall equipment effectiveness (OEE) for mining equipment (shovel-truck): A case study Manisa-Soma (Turkey) open pit mine

Mining is a costly activity that requires huge investments and large equipment. Therefore, it is crucial to use mining equipment efficiently to maximize productivity. This requires the continuous analysis of equipment efficiency and taking action to reduce negative impacts. Accurately estimating equipment efficiency is essential to increase its effectiveness. One globally recognized and accepted measurement is Overall Equipment Effectiveness (OEE). In this study was conducted to calculate the OEE values of shovels and trucks, which are the primary equipment used in open pit mining. The study presented different loss times and quality values while calculating the OEE values of mining equipment. The OEE values of electric trucks and shovels were found to be consistent with actual work quantities in the Manisa-Soma Lignite open pit operation. This study is the first applied study of OEE analysis in Turkey.

Development of methods and means to improve environmental, radiation and industrial safety of NPPs with WWER-1200

The introduction provides an overview of scientific research on the sources of generation, characteristics and classification of infrasound. It is noted that infrasound has a number of features related to the low oscillation frequency of the elastic medium and the diffraction property. Infrasound has harmful effects on hearing, breathing, vision, gastrointestinal tract, nervous and cardiovascular systems, brain and vestibular apparatus, leading to decreased performance, general malaise and premature aging of the human body. The methodology of theoretical substantiation of methods for detecting previously unknown sources of infrasound, improving the environmental, radiation and industrial safety of nuclear power plants with WWER-1200 is based on the use of digital acoustic models of primary circuit equipment responsible for operational safety developed under the guidance of K.N. Proskuryakov. The methodology of practical confirmation of the results of computational and theoretical forecasting of acoustic parameters of previously unknown infrasound sources is presented in the form of two stages: a) development of a methodology for verifying forecasting results and selection of power units No. 1, 2 of Novovoronezh NPP-2 in the form of objects; b) investigation of the conditions for the occurrence of vibro-infrasound resonances in the first circuit. The developed method for investigating infrasound sources has been verified at the WWER-1200 reactor plant. When discussing the results of the conducted research, previously unknown sources of infrasound were identified. Innovative methods of analysis and damping of infrasound sources have been developed and a patent for invention No. 2803181 «A method for preventing resonant interaction of vibrations of water-water power reactor equipment with acoustically standing waves and a device for its implementation» has been obtained. The errors of the chief designer of reactor installations with WWER in the regulations for the launch of new power units are noted; their negative consequences for the health of personnel and the condition of equipment responsible for environmental, radiation and industrial safety of nuclear power plants with WWER are indicated