scholarly journals EXPERIMENTAL INVESTIGATIONS OF EFFECT OF LC-CIRCUITS ON SPARKING AND THERMAL STATE OF SLIDING ELECTRIC CONTACT UNIT

2017 ◽  
Vol 3 ◽  
pp. 150
Author(s):  
Oksana Kozyreva ◽  
Igor Plokhov ◽  
Nikita Kotkov ◽  
Igor Savraev ◽  
Alexander Ilyin
Keyword(s):  
Service Life ◽  
Thermal State ◽  
Sliding Contact ◽  
Practical Significance ◽  
Experimental Investigations ◽  
Thermal Processes ◽  
Physical Processes ◽  
Sliding Electric Contact ◽  
Contact Unit ◽  
The Impact

Such processes in electric machines having sliding contacts as sparking and overheating can be the reason of the deep electroerosive wear. Searching effective ways to reduce sparking has an obvious practical significance since it extends the service life of the sliding contact in particular and service life of the electro-mechanic units in whole. This article contains information about physical processes in the electrical sliding contact. The method of spark suppression related to LC filters introduced to the electromagnetic brush circuits is considered, the device for spark reducing is suggested. The calculations of the impact of the device for spark reducing on sparking and thermal processes in the contact pairs are described.

Definition of the Transfer Function Parameters of Asynchronous Motor as an Object of Temperature Control

2014 ◽  
Vol 698 ◽  
pp. 124-130 ◽  
Author(s):  
Alexander Pugachev ◽  
Galina Fedyaeva
Keyword(s):  
Induction Motors ◽  
Transfer Functions ◽  
Thermal State ◽  
Cooling System ◽  
Asynchronous Motor ◽  
Experimental Investigations ◽  
Thermal Processes ◽  
Variable Speed ◽  
Heating And Cooling ◽  
Definition Of

The analysis and systematization of research methods of thermal state of induction motors including traction ones is done. It is shown that for each type of motor it is necessary to develop its own mathematical model of thermal processes, and its verification should be carried out only on the basis of experimental investigations. The structure and operating principles of the complex developed physical model of the traction electric drive with induction motors is represented. The motors have a cooling system with variable-speed electric fan and subsystem of measurement and recording of monitored parameters. The method and the results of experimental study of the processes of heating and cooling of the induction motor are illustrated. Transfer functions and approximation curves of transients are proposed, their parameters are defined.

EFFICIENT COST MANAGEMENT AS AN IMPORTANT FACTOR OF INCREASING THE COMPETITIVENESS OF THE ECONOMIC SUBJECT

2020 ◽  
Keyword(s):  
Management System ◽  
Structural Model ◽  
Driving Forces ◽  
Cost Management ◽  
Management Accounting ◽  
Practical Significance ◽  
Research Centre ◽  
Experimental Investigations ◽  
Sources Of Information ◽  
Interactive Approach

The research is actual, has a theoretical and applied nature. Theoretical developments at cost management branch of economic organization were illustrated by practical examples. In the work the follow methods are used: abstract-logical, methods of induction and deduction, system and situate approaches, methods of comparative analysis, analysis of breakeven, monographic analysis. The follow sources of information were used: literature, the results of the experimental investigations, carried out in Verkh-nevolzhsky Federal Agrarian Research Centre, observations, carried out at an agricultural organization. Theoretical structural model of cost management was created in a functional way, relationship between elements were designated in it, as well as driving forces of its realization were determined. Such terms as “cost management ” and «management accounting» were specified. The paradigm of a relation to cost process was described. Approaches to realization of cost management system of organization on the basis offlexibility principle were developed. The most important of them are: application of applied programs packages and special program means for computer, organization of feedback, account of functional relationship of cost with production results, cost accounting on elements, places of origin, carriers and centers of responsibility, as well as interactive approach. Some examples which show possibilities of using some instruments of cost management and management accounting for generation of management solutions were described. These instruments are: analysis and planning on the basis of standards of constant and variable costs and flexible cost management in interrelations to other subsystems in management system of organization (in this case it is with technology management. The work is of theoretical and practical significance.

scholarly journals Erosion Transportation Processes as Influenced by Gully Land Consolidation Projects in Highly Managed Small Watersheds in the Loess Hilly–Gully Region, China

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1540
Author(s):  
Qianqian Ji ◽  
Zhe Gao ◽  
Xingyao Li ◽  
Jian’en Gao ◽  
Gen’guang Zhang ◽  
...  
Keyword(s):  
Similarity Theory ◽  
Design Method ◽  
Simulation Method ◽  
Practical Significance ◽  
Land Consolidation ◽  
Small Watershed ◽  
Flood Peak ◽  
Erosion Area ◽  
The Impact ◽  
Erosion Environment

The Loess Hilly–Gully region (LHGR) is the most serious soil erosion area in the world. For the small watershed with high management in this area, the scientific problem that has been paid attention to in recent years is the impact of the land consolidation project on the erosion environment in the gully region. In this study, the 3D simulation method of vegetation, eroded sediment and pollutant transport was innovated based on the principles of erosion sediment dynamics and similarity theory, and the impacts of GLCP were analyzed on the erosion environment at different scales. The verification results show that the design method and the scale conversion relationship (geometric scale: λl = 100) were reasonable and could simulate the transport process on the complex underlying surface of a small watershed. Compared with untreated watersheds, a significant change was the current flood peak lagging behind the sediment peak. There were two important critical values of GLCP impact on the erosion environment. The erosion transport in HMSW had no change when the proportion was less than 0.85%, and increased obviously when it was greater than 3.3%. The above results have important theoretical and practical significance for watershed simulation and land-use management in HMSW.

scholarly journals Analysis of the Welding Type and Filler Metal Influence on Performance of a Regenerated Gear

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1496
Author(s):  
Svetislav Marković ◽  
Dušan Arsić ◽  
Ružica R. Nikolić ◽  
Vukić Lazić ◽  
Nada Ratković ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Service Life ◽  
Economic Analysis ◽  
Filler Metal ◽  
Performance Characteristics ◽  
Experimental Investigations ◽  
Spur Gears ◽  
Soft Filler ◽  
Welding Procedure

This paper presents the results of voluminous experimental investigations conducted to analyze the influence of the welding procedure on the performance of regenerated gears. Cylindrical spur gears were tested, both newly manufactured and regenerated, in two fundamentally different ways: by hard facing (surfacing) with the “hard” filler metal (DUR 600-IG) and with the “soft” filler metal (EVB2CrMo) with subsequent cementation and quenching. The regeneration procedures were defined and executed, while, subsequently, the microstructure and microhardness of the hard-faced layers were established and measured, followed by checking the durability of the hard-faced teeth flanks. Finally, techno-economic analysis was performed to establish the rationality of the conducted regenerations, i.e., the costs of regenerated and newly manufactured teeth were compared. Based on the results of the conducted investigations, it was possible to establish the influence of the welding type on the performance characteristics (primarily the service life) of the regenerated gears. For individual reparatory hard facing, the procedure with the “hard” filler metal exhibited better characteristics, while for batch reparation of numerous damaged gears, the reparation with the “soft” filler metal, followed by cementation and heat treatment, might be more convenient.

scholarly journals Model-Based Control of Torque and Nitrogen Oxide Emissions in a Euro VI 3.0 L Diesel Engine through Rapid Prototyping

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1107
Author(s):  
Stefano d’Ambrosio ◽  
Roberto Finesso ◽  
Gilles Hardy ◽  
Andrea Manelli ◽  
Alessandro Mancarella ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Rapid Prototyping ◽  
Nitrogen Oxide ◽  
Thermal State ◽  
Pollutant Emissions ◽  
Computational Time ◽  
Nox Emissions ◽  
Model Based ◽  
Brake Mean Effective Pressure ◽  
The Impact

In the present paper, a model-based controller of engine torque and engine-out Nitrogen oxide (NOx) emissions, which was previously developed and tested by means of offline simulations, has been validated on a FPT F1C 3.0 L diesel engine by means of rapid prototyping. With reference to the previous version, a new NOx model has been implemented to improve robustness in terms of NOx prediction. The experimental tests have confirmed the basic functionality of the controller in transient conditions, over different load ramps at fixed engine speeds, over which the average RMSE (Root Mean Square Error) values for the control of NOx emissions were of the order of 55–90 ppm, while the average RMSE values for the control of brake mean effective pressure (BMEP) were of the order of 0.25–0.39 bar. However, the test results also highlighted the need for further improvements, especially concerning the effect of the engine thermal state on the NOx emissions in transient operation. Moreover, several aspects, such as the check of the computational time, the impact of the controller on other pollutant emissions, or on the long-term engine operations, will have to be evaluated in future studies in view of the controller implementation on the engine control unit.

scholarly journals Experimental investigations on diesel engine using alumina nanoparticle fuel additive

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402098840
Author(s):  
Mohammed S Gad ◽  
Sayed M Abdel Razek ◽  
PV Manu ◽  
Simon Jayaraj
Keyword(s):  
Diesel Engine ◽  
Diesel Fuel ◽  
Alumina Nanoparticles ◽  
Experimental Investigations ◽  
Fuel Additive ◽  
Alumina Nanoparticle ◽  
Fuel Injectors ◽  
Performance And Emission ◽  
And Performance ◽  
The Impact

Experimental work was done to examine the impact of diesel fuel with alumina nanoparticles on combustion characteristics, emissions and performance of diesel engine. Alumina nanoparticles were mixed with crude diesel in various weight fractions of 20, 30, and 40 mg/L. The engine tests showed that nano alumina addition of 40 ppm to pure diesel led to thermal efficiency enhancement up to 5.5% related to the pure diesel fuel. The average specific fuel consumption decrease about neat diesel fuel was found to be 3.5%, 4.5%, and 5.5% at dosing levels of 20, 30, and 40 ppm, respectively at full load. Emissions of smoke, HC, CO, and NOX were found to get diminished by about 17%, 25%, 30%, and 33%, respectively with 40 ppm nano-additive about diesel operation. The smaller size of nanoparticles produce fuel stability enhancement and prevents the fuel atomization problems and the clogging in fuel injectors. The increase of alumina nanoparticle percentage in diesel fuel produced the increases in cylinder pressure, cylinder temperature, heat release rate but the decreases in ignition delay and combustion duration were shown. The concentration of 40 ppm alumina nanoparticle is recommended for achieving the optimum improvements in the engine’s combustion, performance and emission characteristics.

scholarly journals A FEM-Based 2D Model for Simulation and Qualitative Assessment of Shot-Peening Processes

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2784
Author(s):  
Georgios Maliaris ◽  
Christos Gakias ◽  
Michail Malikoutsakis ◽  
Georgios Savaidis
Keyword(s):  
Process Parameters ◽  
Material Properties ◽  
Shot Peening ◽  
Qualitative Assessment ◽  
Experimental Investigations ◽  
Elastoplastic Material ◽  
Size Distributions ◽  
User Friendly ◽  
The Impact ◽  
2D Model

Shot peening is one of the most favored surface treatment processes mostly applied on large-scale engineering components to enhance their fatigue performance. Due to the stochastic nature and the mutual interactions of process parameters and the partially contradictory effects caused on the component’s surface (increase in residual stress, work-hardening, and increase in roughness), there is demand for capable and user-friendly simulation models to support the responsible engineers in developing optimal shot-peening processes. The present paper contains a user-friendly Finite Element Method-based 2D model covering all major process parameters. Its novelty and scientific breakthrough lie in its capability to consider various size distributions and elastoplastic material properties of the shots. Therewith, the model is capable to provide insight into the influence of every individual process parameter and their interactions. Despite certain restrictions arising from its 2D nature, the model can be accurately applied for qualitative or comparative studies and processes’ assessments to select the most promising one(s) for the further experimental investigations. The model is applied to a high-strength steel grade used for automotive leaf springs considering real shot size distributions. The results reveal that the increase in shot velocity and the impact angle increase the extent of the residual stresses but also the surface roughness. The usage of elastoplastic material properties for the shots has been proved crucial to obtain physically reasonable results regarding the component’s behavior.

scholarly journals System Dynamics Model for the Evolutionary Behaviour of Government Enterprises and Consumers in China’s New Energy Vehicle Market

2020 ◽  
Vol 12 (4) ◽  
pp. 1578 ◽  
Author(s):  
Hongxia Sun ◽  
Yao Wan ◽  
Huirong Lv
Keyword(s):  
System Dynamics ◽  
Motor Vehicle ◽  
Replicator Dynamics ◽  
Evolutionary Game ◽  
Practical Significance ◽  
Subsidy Policy ◽  
New Energy ◽  
New Energy Vehicle ◽  
The Impact ◽  
Vehicle Market

Exhaust pollution and energy crises are worsening worldwide. China has become the largest motor vehicle producer; thus, promoting the use of new energy vehicles (NEVs) in China has important practical significance. In this paper, considering the limited rationality of governments, NEV enterprises and consumers, we study the subsidy policy of the China NEV market using the evolutionary game and system dynamics (SD) methods. First, a tripartite evolutionary game model is developed and the replicator dynamics equations and Jacobian matrix are obtained. A SD simulation of the model was conducted to further clarify the impact of the initial market proportion and three variables used in the model. The results show that the initial market proportion affects the evolution speed but does not affect the evolution result when the three group players all choose a mixed strategy. For governments, they should not hastily cancel price subsidies provided to consumers; rather, they should dynamically adjust the rate of the subsidy decrease and increase the consumers’ extra cost for purchasing fuel vehicles (FVs). NEV enterprises should appropriately increase their investments in the research and development (R&D) of NEVs.

Assessment of Unsteady Flows in Turbines

1992 ◽  
Vol 114 (1) ◽  
pp. 79-90 ◽  
Author(s):  
O. P. Sharma ◽  
G. F. Pickett ◽  
R. H. Ni
Keyword(s):  
Unsteady Flow ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Experimental Investigations ◽  
Flow Parameters ◽  
Research Activities ◽  
Flow Features ◽  
Computational Fluid Dynamics Cfd ◽  
Turbine Design ◽  
The Impact

The impacts of unsteady flow research activities on flow simulation methods used in the turbine design process are assessed. Results from experimental investigations that identify the impact of periodic unsteadiness on the time-averaged flows in turbines and results from numerical simulations obtained by using three-dimensional unsteady Computational Fluid Dynamics (CFD) codes indicate that some of the unsteady flow features can be fairly accurately predicted. Flow parameters that can be modeled with existing steady CFD codes are distinguished from those that require unsteady codes.

scholarly journals Ocean resurge-induced impact melt dynamics on the peak-ring of the Chicxulub impact structure, Mexico

2021 ◽  
Author(s):  
Felix M. Schulte ◽  
◽  
Axel Wittmann ◽  
Stefan Jung ◽  
Joanna V. Morgan ◽  
...  
Keyword(s):  
Impact Structure ◽  
Physical Processes ◽  
Hydrothermal Conditions ◽  
Chemical Examination ◽  
Impact Melt ◽  
Target Rock ◽  
Single Process ◽  
Chicxulub Impact ◽  
The Impact

AbstractCore from Hole M0077 from IODP/ICDP Expedition 364 provides unprecedented evidence for the physical processes in effect during the interaction of impact melt with rock-debris-laden seawater, following a large meteorite impact into waters of the Yucatán shelf. Evidence for this interaction is based on petrographic, microstructural and chemical examination of the 46.37-m-thick impact melt rock sequence, which overlies shocked granitoid target rock of the peak ring of the Chicxulub impact structure. The melt rock sequence consists of two visually distinct phases, one is black and the other is green in colour. The black phase is aphanitic and trachyandesitic in composition and similar to melt rock from other sites within the impact structure. The green phase consists chiefly of clay minerals and sparitic calcite, which likely formed from a solidified water–rock debris mixture under hydrothermal conditions. We suggest that the layering and internal structure of the melt rock sequence resulted from a single process, i.e., violent contact of initially superheated silicate impact melt with the ocean resurge-induced water–rock mixture overriding the impact melt. Differences in density, temperature, viscosity, and velocity of this mixture and impact melt triggered Kelvin–Helmholtz and Rayleigh–Taylor instabilities at their phase boundary. As a consequence, shearing at the boundary perturbed and, thus, mingled both immiscible phases, and was accompanied by phreatomagmatic processes. These processes led to the brecciation at the top of the impact melt rock sequence. Quenching of this breccia by the seawater prevented reworking of the solidified breccia layers upon subsequent deposition of suevite. Solid-state deformation, notably in the uppermost brecciated impact melt rock layers, attests to long-term gravitational settling of the peak ring.

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