scholarly journals ON THE TECHNIQUE OF MISMATCHING THE RESONANT INTERACTIONS OF THE SOUND FIELDS CAUSED BY TECHNICAL OBJECTS WITH THEIR OWN ACOUSTIC MODES IN THE AIR VOLUME OF ROOMS

Akustika ◽  
2019 ◽  
Vol 32 ◽  
pp. 24-29
Author(s):  
Mikhail Fesina ◽  
Igor Deryabin ◽  
Gorina Larisa
Keyword(s):  
Power Systems ◽  
Internal Combustion Engines ◽  
Acoustic Vibration ◽  
Production Equipment ◽  
Cavity Resonance ◽  
Vibration Frequencies ◽  
Diesel Generator ◽  
Air Cavity ◽  
Resonant Interactions ◽  
Operation Conditions

Noise generating production equipment, which is located in technical rooms, first of all, is represented as power systems (pump and compressor stations, internal combustion engines, diesel-generator units, power electric transformers and electric engines, ventilation systems and air conditioning systems). As a rule, these systems operate on nominal permanent speed operation conditions ns. In their wideband sound radiation spectrum, there are found dominant discrete components which are concentrated in audio spectrum fms = 50…500 Hz, and which are characterized by corresponding sound wavelengths λms. Also, acoustic and temperature eigen fields are appeared in described volumetric air cavity of a technical room, and characterized by acoustic eigenmodes on acoustic vibration frequencies fmА and by sound wavelength λmА. Offered technical methods let eliminate the development of intensive air cavity resonance of sound radiations with proximate values of acoustic vibration frequencies fms and fmА, and sound wavelengths λms and λmА.

Plane Wave Resonance in the Tire Air Cavity as a Vehicle Interior Noise Source

1995 ◽  
Vol 23 (1) ◽  
pp. 2-10 ◽  
Author(s):  
J. K. Thompson
Keyword(s):  
Closed Form Solution ◽  
Form Solution ◽  
Interior Noise ◽  
Cavity Resonance ◽  
Test Results ◽  
Vehicle Interior ◽  
Air Cavity ◽  
Vehicle Interior Noise ◽  
Wave Resonance ◽  
Resonance Frequencies

Abstract Vehicle interior noise is the result of numerous sources of excitation. One source involving tire pavement interaction is the tire air cavity resonance and the forcing it provides to the vehicle spindle: This paper applies fundamental principles combined with experimental verification to describe the tire cavity resonance. A closed form solution is developed to predict the resonance frequencies from geometric data. Tire test results are used to examine the accuracy of predictions of undeflected and deflected tire resonances. Errors in predicted and actual frequencies are shown to be less than 2%. The nature of the forcing this resonance as it applies to the vehicle spindle is also examined.

scholarly journals Design and Research on Power Systems and Algorithms for Controlling Electric Underground Mining Machines Powered by Batteries

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4060
Author(s):  
Artur Kozłowski ◽  
Łukasz Bołoz
Keyword(s):  
Power Systems ◽  
Power Supply ◽  
Internal Combustion Engines ◽  
Underground Mining ◽  
Test Stand ◽  
Research Network ◽  
Control Algorithms ◽  
Systems And Control ◽  
And Control ◽  
Supply Systems

This article discusses the work that resulted in the development of two battery-powered self-propelled electric mining machines intended for operation in the conditions of a Polish copper ore mine. Currently, the global mining industry is seeing a growing interest in battery-powered electric machines, which are replacing solutions powered by internal combustion engines. The cooperation of Mine Master, Łukasiewicz Research Network—Institute of Innovative Technologies EMAG and AGH University of Science and Technology allowed carrying out a number of works that resulted in the production of two completely new machines. In order to develop the requirements and assumptions for the designed battery-powered propulsion systems, underground tests of the existing combustion machines were carried out. Based on the results of these tests, power supply systems and control algorithms were developed and verified in a virtual environment. Next, a laboratory test stand for validating power supply systems and control algorithms was developed and constructed. The tests were aimed at checking all possible situations in which the battery gets discharged as a result of the machine’s ride or operation and when it is charged from the mine’s mains or with energy recovered during braking. Simulations of undesirable situations, such as fluctuations in the supply voltage or charging power limitation, were also carried out at the test stand. Positive test results were obtained. Finally, the power supply systems along with control algorithms were implemented and tested in the produced battery-powered machines during operational trials. The power systems and control algorithms are universal enough to be implemented in two different types of machines. Both machines were specially designed to substitute diesel machines in the conditions of a Polish ore mine. They are the lowest underground battery-powered drilling and bolting rigs with onboard chargers. The machines can also be charged by external fast battery chargers.

Nanoparticle–Fluid Interactions at Ultrahigh Acoustic Vibration Frequencies Studied by Femtosecond Time-Resolved Microscopy

ACS Nano ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 1833-1840
Author(s):  
Kuai Yu ◽  
Yang Yang ◽  
Junzhong Wang ◽  
Gregory V. Hartland ◽  
Guo Ping Wang
Keyword(s):  
Acoustic Vibration ◽  
Vibration Frequencies ◽  
Time Resolved ◽  
Fluid Interactions

scholarly journals Energy Demand Analysis and Design of a Hybrid Power System in Bawean Islands, Indonesia

2018 ◽  
Vol 164 ◽  
pp. 01038
Author(s):  
Ridho Hantoro ◽  
Cahyun Budiono ◽  
Ronald Kipkoech Ketter ◽  
Nyoman Ade Satwika
Keyword(s):  
Power Systems ◽  
Energy Demand ◽  
Peak Load ◽  
Electricity Consumption ◽  
Simulation Software ◽  
Diesel Generator ◽  
Time Step ◽  
Analysis And Design ◽  
Optimum System ◽  
Hybrid Power

Over 70 000 000 people in Indonesia have no access to electricity. This study was carried out in Bawean Islands which are located in the Java Sea about 150 km North of Surabaya, the headquarters of East Java. The study to determine the energy services available in the Bawean Island was done through interviewing a random sample of 72 households in two villages namely Komalasa and Lebak. Based on the average monthly electricity consumption of the sampled households connected to the grid, a hybrid renewable energy based electrical supply system was designed for Gili Timur Island, one of the satellite islands around Bawean Island. The system was designed with the aid of a time step simulation software used to design and analyze hybrid power systems. A sensitivity analysis was also carried out on the optimum system to study the effects of variation in some of the system variables. HOMER suggests that for the expected peak load of 131 kW, an optimum system will consist of 150 kW from PV array, two wind turbines each rated 10 kW, a 75 kW diesel generator and batteries for storage.

scholarly journals Determination of reliability of power supply of ship's responsible power receivers

2020 ◽  
pp. 22-26
Author(s):  
С.Е. Кузнецов ◽  
Н.А. Алексеев ◽  
А.А. Виноградов
Keyword(s):  
Power Systems ◽  
Power System ◽  
Power Supply ◽  
Electric Power System ◽  
Time To Failure ◽  
Parallel Operation ◽  
Diesel Generator ◽  
Operating Modes ◽  
Reliability Indicators ◽  
Supply Reliability

Изложена методика расчета показателей безотказности электроснабжения (вероятности безотказного электроснабжения и средней наработки до отказа) ответственных приемников морского судна, подключаемых к аварийному электрораспределительному щиту. Методика реализована применительно к судовой электроэнергетической системе с тремя источниками электроэнергии – двумя основными дизель-генераторными агрегатами, подключенными к главному электрораспределительному щиту, и одним аварийным дизель-генераторным агрегатом, подключенным к аварийному электрораспределительному щиту. Рассмотрены различные режимы работы судовой электроэнергетической системы: при работе до первого отказа одного основного дизель-генератора, при параллельной работе двух основных дизель-генераторов, при работе одного аварийного дизель-генератора; а также после обесточивания с учетом возможности последующего включения резервного или (и) аварийного дизель генератора. Методика, с соответствующими корректировками, может быть использована для расчета показателей безотказного электроснабжения в судовых электроэнергетических системах другой комплектации. Расчет показателей безотказности электроснабжения необходим при проектировании для обеспечения требуемого уровня надежности электроснабжения судовых приемников электроэнергии, а при эксплуатации – для предупреждения отказов и планирования технического обслуживания и ремонта элементов судовых электроэнергетических систем. The methodology for calculating the indicators of the reliability of power supply (the probability of failure-free power supply and the mean time to failure) of critical receivers of a sea vessel connected to the emergency electrical switchboard is presented. The technique is implemented in relation to a ship power system with three sources of electricity - two main diesel generator sets connected to the main electrical switchboard, and one emergency diesel generator set connected to an emergency electrical switchboard. Various operating modes of the ship's electric power system are considered: during operation until the first failure of one main diesel generator, during parallel operation of two main diesel generators, during operation of one emergency diesel generator; as well as after de-energizing, taking into account the possibility of subsequent switching on of the backup and / or emergency diesel generator. The technique, with appropriate adjustments, can be used to calculate indicators of reliable power supply in ship power systems of a different configuration. Calculation of power supply reliability indicators is necessary during design to ensure the required level of power supply reliability for ship power receivers, and during operation - to prevent failures and plan maintenance and repair of elements of ship power systems.

scholarly journals Comparison between 1-D and grey-box models of a SOFC

2019 ◽  
Vol 128 ◽  
pp. 01007
Author(s):  
Ramin Moradi ◽  
Andrea Di Carlo ◽  
Federico Testa ◽  
Luca Del Zotto ◽  
Enrico Bocci ◽  
...  
Keyword(s):  
Power Systems ◽  
Solid Electrolyte ◽  
Gas Turbines ◽  
Internal Combustion Engines ◽  
Box Model ◽  
System Level ◽  
Internal Temperature ◽  
Box Models ◽  
The Impact ◽  
D Model

Solid Oxide Fuel Cells (SOFCs) have shown unique performance in terms of greater electrical efficiency and thermochemical integrity with the power systems compared to gas turbines and internal combustion engines. Nonetheless, simple and reliable models still must be defined. In this paper, a comparisonbetween a grey-box model and a 1-D model of a SOFC is performed to understand the impact of the heat transfer inside the cell on the internal temperature distribution of the solid electrolyte. Hence, a significant internal temperature peak of the solid electrolyte is observed for a known difference between anode and cathode inlet temperatures. Indeed, it highlights the difference between the 1-D model andthe grey-box model regarding the thermal conditioning of the SOFC. Therefore, the results of this study can be used to investigate the reliability of the thermal results of box models in system-level simulations.

Application of Nonlinear Vibration Absorbers to the Control of Piston Secondary Motion in Internal Combustion Engines

2015 ◽  
Author(s):  
Nader Dolatabadi ◽  
Stephanos Theodossiades ◽  
Steve J. Rothberg
Keyword(s):  
Internal Combustion Engines ◽  
Passive Control ◽  
Internal Combustion ◽  
Impact Behavior ◽  
Combustion Engines ◽  
Impulsive Behavior ◽  
Control Approach ◽  
Operation Conditions ◽  
Secondary Motion ◽  
Nonlinear Energy

The impulsive behavior of piston plays a key role in the Noise, Vibration and Harshness (NVH) of internal combustion engines. There have been several studies on the identification and quantification of piston impacting action under various operation conditions. In the current study, the dynamics of piston secondary motion are briefly explored, since this is fundamental to understanding the aggressive oscillations, energy loss and noise generation. Concepts of controlling piston secondary motion (and thus, impacts) are investigated and a new passive control approach is presented based on the nonlinear energy absorption of the highly transient oscillations. The effectiveness of this new method on the improvement of piston impact behavior is discussed, using a preliminary optimization exercise (with respect to engine excitation/speed, damping and stiffness of the nonlinear oscillator) that leads to the conceptual design of a nonlinear energy absorber.

scholarly journals The effect of an enclosed air cavity on a rectangular drum

1983 ◽  
Vol 24 (3) ◽  
pp. 343-349 ◽  
Author(s):  
H. P. W. Gottlieb
Keyword(s):  
Green’S Function ◽  
Frequency Shift ◽  
Green's Function ◽  
Natural Vibration ◽  
Frequency Equation ◽  
Vibration Frequencies ◽  
Air Cavity ◽  
First Order ◽  
Degenerate Mode ◽  
Function Formulation

AbstractThe effect of an enclosed air cavity on the natural vibration frequencies of a rectangular membrane is investigated. The modes specified by an even integer are not affected. For the odd-odd modes, the frequency equation is found via a Green's function formulation and is solved to first order in a parameter representing the effect of the cavity of the rectangular drum. The frequencies are raised, with the fundamental being most affected. In the case of degeneracies, each degenerate mode contributes to the frequency shift, but the degeneracy itself is not broken to first order.

Adaptive Neuro-Fuzzy Synchronization in Isolated Power Systems with High Wind Penetration

2016 ◽  
Vol 20 (3) ◽  
pp. 418-428
Author(s):  
Michael Negnevitsky ◽  
◽  
Dusan Nikolic ◽  
Martin de Groot ◽  
◽  
...  
Keyword(s):  
Power Systems ◽  
Diesel Generator ◽  
Synchronization Problem ◽  
Neuro Fuzzy ◽  
Harmful Emissions ◽  
Diesel Generators ◽  
The Stability ◽  
Systems Simulation ◽  
System Frequency

Isolated power systems (IPSs) worldwide are traditionally powered by diesel generators that are very expensive to run and produce harmful emissions. In order to mitigate these problems, wind turbines are being introduced into existing IPSs. Although this integration has been reasonably effective at reducing running costs and emissions, high levels of wind penetration cause large system frequency variations, resulting in a prolonged synchronization process for newly dispatched diesel generators. Long synchronization can compromise the stability of a small IPS. This paper examines the diesel synchronization problem using a real IPS as a case study and offers a solution by introducing the concept of predictive synchronization based on adaptive neuro-fuzzy systems. Simulation results demonstrate a significant reduction in diesel generator synchronization times.

Development of Electric Bicycle Performance Testing Techniques and Adaptable Electric Bicycle Power System

2007 ◽  
Author(s):  
Richard V. Stackhouse ◽  
Zuomin Dong
Keyword(s):  
Power Systems ◽  
Power System ◽  
Standardized Testing ◽  
Internal Combustion Engines ◽  
Low Cost ◽  
Performance Testing ◽  
Combustion Engines ◽  
Testing Facility ◽  
Electric Bicycle ◽  
Electric Bicycles

Battery powered electric bicycles and scooters, replacing the heavily polluting scooters with two-cycle internal combustion engines, provide zero-emission transportation for many parts of the world. Annual global sales of electric bicycles have risen from 36,000 in 1993 to over 500,000 in 1999 and to multi-millions today. To facilitate the development of new electric bicycles, a computerized electric bicycle testing facility has been created. Standardized testing cycles for quantitatively measuring the performance of electric bicycles have been developed. Testing results of three representative electric bicycles using the newly introduced electric bicycle testing methods and testing facility are presented. The development of a low-cost, fully Adaptable Electric Bicycle Power System (AEBPS) designed to be quickly adapted to a regular bicycle is also presented. The AEBPS can be attached to a regular bicycle in less than ten minutes, and removed in under five minutes. Performance of a converted bicycle using the AEBPS is evaluated and compared with representative commercial electric bicycles. The work forms the foundation for systematically evaluating different electric bicycle designs and for carrying out design optimization of electric bicycle power systems suitable to different markets and needs.

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