scholarly journals Alignment Methods in Rotating Equipment

2020 ◽  
Vol 4 (9) ◽  
pp. 107-112
Author(s):  
Isitro Trejo Moreno ◽  
Yair de Jesús González Pérez ◽  
Oscar Hernández Hernández ◽  
Aline Díaz Ramírez ◽  
José Luis Hernández Corona ◽  
...  
Keyword(s):  
Energy Consumption ◽  
High Temperature ◽  
Straight Edge ◽  
Advantages And Disadvantages ◽  
Laser Alignment ◽  
Rotating Equipment ◽  
Dial Indicator

This research provides an analysis about the need to implement innovative alignment techniques and to diversify the methods to carry it out, if there is outdated equipment, misalignment becomes more recurrent and this causes the equipment to present failures as high vibration, high temperature, product leaks, excessive energy consumption and wear of some equipment components. In turn, this text exposes the methodologies of alignment of axes by straight edge, dial indicator, and by laser alignment, and makes a comparison of the advantages and disadvantages between these three methods to conclude which of them brings greater benefits to the industry today.

scholarly journals Fire-Safe Polymer Composites: Flame-Retardant Effect of Nanofillers

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 540
Author(s):  
Yukyung Kim ◽  
Sanghyuck Lee ◽  
Hyeonseok Yoon
Keyword(s):  
Organic Matter ◽  
High Temperature ◽  
Flame Retardant ◽  
Flame Retardants ◽  
Combustion Process ◽  
Polymeric Materials ◽  
Fire Performance ◽  
Gaseous Species ◽  
Advantages And Disadvantages ◽  
Temperature Conditions

Currently, polymers are competing with metals and ceramics to realize various material characteristics, including mechanical and electrical properties. However, most polymers consist of organic matter, making them vulnerable to flames and high-temperature conditions. In addition, the combustion of polymers consisting of different types of organic matter results in various gaseous hazards. Therefore, to minimize the fire damage, there has been a significant demand for developing polymers that are fire resistant or flame retardant. From this viewpoint, it is crucial to design and synthesize thermally stable polymers that are less likely to decompose into combustible gaseous species under high-temperature conditions. Flame retardants can also be introduced to further reinforce the fire performance of polymers. In this review, the combustion process of organic matter, types of flame retardants, and common flammability testing methods are reviewed. Furthermore, the latest research trends in the use of versatile nanofillers to enhance the fire performance of polymeric materials are discussed with an emphasis on their underlying action, advantages, and disadvantages.

Optimization of Active Magnetic Bearings’ Power Supply System for Main Helium Fan in High Temperature Gas-Cooled Reactor

2021 ◽  
Author(s):  
Huan Luo ◽  
Zhengang Shi ◽  
Yan Zhou ◽  
Ni Mo
Keyword(s):  
High Temperature ◽  
Power Supply ◽  
Power Supply System ◽  
Magnetic Bearing ◽  
Supply System ◽  
Buck Converter ◽  
Normal Operation ◽  
Rotating Equipment ◽  
Amb System ◽  
High Temperature Gas

Abstract High temperature gas-cooled reactor (HTR) is a kind of reactor with inherent safety developed by Institute of Nuclear Energy and New Energy Technology of Tsinghua University. In the first circuit, pure helium is used as coolant and the main helium fan is used to promote the coolant circulation. In order to meet the requirements of service environment and performance, the main helium fan adopts the non-lubricant active magnetic bearing (AMB) system as its support system. For the high-speed rotating equipment supported by AMBs, losing power would lead to bearing failure and cause serious damage to the equipment. In this paper, the power supply system of AMBs is optimized. The power supply of AMB system is connected with the DC-link of the motor converter through DC/DC converter. During normal operation, the AMB system is supplied by external power supply, and the DC/DC converter is used as the backup redundant power supply. In the event of a power failure accident, the DC/DC converter is put into operation, converting the remanet kinetic energy of the motor into stable power to maintain the normal operation of the AMB system. The DC/DC converter adopts two-stage topology structure of the former BUCK converter and the later LLC converter, and completes the voltage stabilization control of the latter LLC converter through the digital signal processor (DSP). Experimental results show that this scheme can realize the power loss protection function of the rotating equipment supported by AMBs.

scholarly journals A Multi-Objective Particle Swarm Optimization for Trajectory Planning of Fruit Picking Manipulator

Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2286
Author(s):  
Xiaoman Cao ◽  
Hansheng Yan ◽  
Zhengyan Huang ◽  
Si Ai ◽  
Yongjun Xu ◽  
...  
Keyword(s):  
Particle Swarm Optimization ◽  
Energy Consumption ◽  
Evaluation Method ◽  
Technical Problem ◽  
Particle Swarm ◽  
Optimal Solution ◽  
Swarm Optimization ◽  
Multi Objective ◽  
Advantages And Disadvantages ◽  
Optimal Evaluation

Stable, efficient and lossless fruit picking has always been a difficult problem, perplexing the development of fruit automatic picking technology. In order to effectively solve this technical problem, this paper establishes a multi-objective trajectory model of the manipulator and proposes an improved multi-objective particle swarm optimization algorithm (represented as GMOPSO). The algorithm combines the methods of mutation operator, annealing factor and feedback mechanism to improve the diversity of the population on the basis of meeting the stable motion, avoiding the local optimal solution and accelerating the convergence speed. By adopting the average optimal evaluation method, the robot arm motion trajectory has been testified to constructively fulfill the picking standards of stability, efficiency and lossless. The performance of the algorithm is verified by ZDT1~ZDT3 benchmark functions, and its competitive advantages and disadvantages with other multi-objective evolutionary algorithms are further elaborated. In this paper, the algorithm is simulated and verified by practical experiments with the optimization objectives of time, energy consumption and pulsation. The simulation results show that the solution set of the algorithm is close to the real Pareto frontier. The optimal solution obtained by the average optimal evaluation method is as follows: the time is 34.20 s, the energy consumption is 61.89 °/S2 and the pulsation is 72.18 °/S3. The actual test results show that the trajectory can effectively complete fruit picking, the average picking time is 25.5 s, and the success rate is 96.67%. The experimental results show that the trajectory of the manipulator obtained by GMOPSO algorithm can make the manipulator run smoothly and facilitates efficient, stable and nondestructive picking.

scholarly journals Creep Rupture Analysis of Candidate Steels for the Traveling Wave Reactor

2018 ◽  
Author(s):  
Cheng Xu
Keyword(s):  
High Temperature ◽  
Yield Stress ◽  
Traveling Wave ◽  
Rupture Strength ◽  
Creep Rupture ◽  
Thermal Creep ◽  
Uniaxial Tensile ◽  
Advantages And Disadvantages ◽  
Analysis Methods ◽  
Best Estimate

TerraPower has developed sophisticated computational analysis tools to support the design and fabrication of high temperature components to be used in the Traveling Wave Reactor (TWR). One of the key material properties required to predict material damage and remaining lifetime of key in-reactor components is the thermal creep rupture time. Although TerraPower optimized ferritic-martensitic (FM) HT9 steel has shown consistent improvement in yield stress and creep rupture strength through uniaxial tensile tests, extrapolations of existing test data are still needed to fully support the complex analysis used in the TWR design. Traditional Larson-Miller analysis for creep rupture was used to compare the TerraPower optimized HT9 steel to the existing historical database. The results of the Larson-Miller analysis were compared to the results from the Wilshire analysis to explore the relative advantages and disadvantages of each method. The best estimate values for fitting constants and activation energies were determined for both methods, taking into account the effects of the higher yield stress observed in TerraPower optimized HT9 compared to historic HT9. Likewise, the best estimate creep rupture stresses for TerraPower optimized HT9 at various times and temperatures were determined by extrapolations using both the Larson-Miller and Wilshire analysis. The allowable stresses of historical and TerraPower optimized HT9 steels were compared to those of existing materials (9Cr-1Mo-V) in the ASME high temperature code. The comparison of analysis methods and rupture stresses demonstrate that TerraPower FM steel thermal creep performance and analysis methods are comparable to existing ASME qualified materials for high temperature applications.

Developing and Implementing Ch. VII O&M Programs at CCGT Plants: Case Studies

2021 ◽  
Author(s):  
Peter Jackson ◽  
Robert Rosario ◽  
Andreas Fabricius ◽  
Anita Johny ◽  
Alexandria Wholey
Keyword(s):  
High Temperature ◽  
High Energy ◽  
Piping System ◽  
Inspection Planning ◽  
Accelerated Corrosion ◽  
Advantages And Disadvantages ◽  
Effective Implementation ◽  
Creep Fatigue ◽  
The Usa ◽  
High Temperature Steam

Abstract We will present the results from several projects from the USA and other jurisdictions where ASME B31.1 Ch. VII O&M Covered Piping System (CPS) Programs have been implemented at several types of natural gas-fired CCGT plants. Common elements of programs for different plants will be summarized as well as plant-specific considerations for high energy piping condition assessment for newer plants. Pros and cons between a common program for a thermal fleet and plant-specific programs will be discussed including advantages and disadvantages of each approach. Effective implementation of parts of the Nonmandatory Appendix V guidance within the CPS Program will be described and recommendations for best practices. A brief overview of degradation-specific mechanisms for high energy piping and approaches for planninng/scheduling NDE inspections will be described. This overview will include: creep, fatigue, corrosion (erosion-corrosion - E/C and flow accelerated corrosion - FAC) as well as mechanisms that are commonly responsible for high energy piping leaks, failures and repairs including thermal quench cracking of HRSG interstage, terminal desuperheaters and turbine bypass attemperators. A brief summary of Gr. 91 inspection planning in Ch. VII O&M Programs will also be included as well as corrosion under insulation (CUI) and common inspection scopes for high temperature steam drains. Resolution of constant force and variable spring pipe supports on high pressure/high temperature piping that are not accommodating thermal expansion as per their engineering design can be evaluated using pre-outage pipe stress models and data obtained from field walkdowns to support rapid decisions for repair/replacement in the field. Finally, experiences with long term scheduling the need for adaptive management of the CPS Programs will be summarized with typical management oversight actions described for effective implementation.

Research on Time Synchronization Algorithm in Wireless Sensor Networks

2011 ◽  
Vol 403-408 ◽  
pp. 1397-1400
Author(s):  
Ping Wang ◽  
Shi Wu Xu
Keyword(s):  
Wireless Sensor Networks ◽  
Energy Consumption ◽  
Sensor Networks ◽  
Time Synchronization ◽  
Wireless Sensor ◽  
Advantages And Disadvantages ◽  
Synchronization Algorithm ◽  
Lower Complexity ◽  
Reduce Energy Consumption

Time synchronization is important for many applications in Wireless Sensor Networks, how to improve synchronization precision and reduce energy consumption are the two important aspects in Wireless Sensor Networks. In this paper, first, we introduce the TPSN and DMTS algorithms, after analyzing the advantages and disadvantages of both. Make use of two algorithms have been integrated. We proposed a DMSN time synchronization algorithm. Experiments show that ,comparing with the TPSN algorithm, DMSN algorithm has lower complexity and energy consumption．It can be easily applied in Wireless Sensor Networks．

A New Method for Desalination of Seawater With Steam-Ejector Refrigeration Plant

2011 ◽  
Vol 94-96 ◽  
pp. 273-279 ◽  
Author(s):  
Jin Zeng Chen ◽  
Yan Fei Li ◽  
G. H Li
Keyword(s):  
Energy Consumption ◽  
Arid Regions ◽  
Cooling Water ◽  
Hybrid Plant ◽  
Heat Energy ◽  
New Method ◽  
Distillation Method ◽  
Advantages And Disadvantages ◽  
Steam Ejector ◽  
The World

Desalination of seawater has played an important role in many arid regions in the world. There are many methods for desalination of seawater, such as MED, MSF, RO, ED, TVC, and MVC, etc. Different methods have different advantages and disadvantages. In the present work, a new method for desalination of seawater with steam-ejector refrigeration plant was introduced. The main purpose of the new method is a hybrid plant of TVC and steam-ejector refrigeration. In the hybrid circle, no other energy was need. When the steam-ejector refrigeration plant is working, the seawater as cooling water is introduced into evaporator of TVC and evaporates. The vapor getting in TVC is extracted by a second steam-ejector, together with the active steam, is used as source of heat for desalination. The main advantage of this hybrid plant is that part of the heat energy of cooling water in refrigeration is reused. Comparing with other distillation method desalination of seawater, the energy consumption is much less. Especially on marine usage, the advantage is clear.

On the Methods for Measuring High Temperature Resistivity of Glass

2016 ◽  
Vol 680 ◽  
pp. 39-43
Author(s):  
Ying Liang Tian ◽  
Mei Zhang ◽  
Yong Ming Li ◽  
Feng Wang ◽  
Jing Ting Yang
Keyword(s):  
High Temperature ◽  
Test Procedure ◽  
Aluminosilicate Glass ◽  
Voltage Measurement ◽  
Advantages And Disadvantages ◽  
Measurement Results ◽  
Accuracy Of Measurement ◽  
High Alkali ◽  
Increasing Temperature ◽  
Temperature Resistivity

This paper described three methods for measuring high temperature resistivity of glass including their basic principles, advantages and disadvantages so as to provide a reference for measurement. The effects of electrode and voltage on high temperature resistivity were studied. Accuracy of measurement results of plate electrodes is better than wire electrodes. The resistivity of molten glass decreased with increasing AC voltage. Measurement results are stable when the voltage is less than 10 V, but when the voltage exceeds than 40 V, Joule heating effect will be generated resulting in smaller measurement values. In addition, high alkali aluminosilicate glass as object is used to introduce test procedure of temperature resistivity and explore the relationship between high temperature resistivity and alkali metal. Results show that high alkali aluminosilicate glass resistivity decreases with increasing temperature, and the effect of K2O on high tempearature resistivity is more pronounced.

Paper 16: Case for the Single-Shaft Vehicular Gas Turbine Engine

1968 ◽  
Vol 183 (14) ◽  
pp. 156-176 ◽  
Author(s):  
A. F. McLean
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Fuel Consumption ◽  
Fuel Economy ◽  
Lower Cost ◽  
Turbine Engine ◽  
Advantages And Disadvantages ◽  
Initial Cost ◽  
Variable Transmission ◽  
Infinitely Variable Transmission

This paper reviews gas turbine cycles most favoured for vehicular use. It suggests the single-shaft turbine engine as a possible contender for a lower cost approach, where fuel economy requirements are not met by complexity of cycle but by operation at higher turbine inlet temperatures. The question, ‘Where does the engine end and the transmission begin?’ is discussed, and an example of an infinitely variable transmission is explored as a means for overcoming the performance deficiencies of the single-shaft machine. The paper examines the advantages and disadvantages of this type of turbine engine with respect to acceleration and torque characteristics, fuel consumption, engine braking, initial cost, and design for simplicity and high temperature.

The Research on the Index of High Temperature Performance of Asphalt Mixture in Airfield

2013 ◽  
Vol 723 ◽  
pp. 1076-1083 ◽  
Author(s):  
Ping Li ◽  
Lie Ping Wang ◽  
Wei Lei ◽  
Bao Lin Xiong
Keyword(s):  
Shear Strength ◽  
High Temperature ◽  
Dynamic Stability ◽  
Asphalt Mixture ◽  
Evaluation Index ◽  
Design Parameters ◽  
Advantages And Disadvantages ◽  
Temperature Performance ◽  
Performance Evaluation Index ◽  
Wheel Tracking

In order to solve current airfield asphalt road surface high temperature performance evaluation index defective problem, we apply the humbug wheel tracking test, general rutting test and uniaxial penetration test ,and use different evaluation index to carry on the analysis. Test results show that shear strength index and rutting test index on the contrary, regression dynamic stability can't distinguish between SMA - 13 and AC - 20 high temperature performance advantages and disadvantages, creep slope and dynamic stability index consistent; At the same time, the use of bailey method design parameters and asphalt cement parameters on its verification found that bailey method can further explain mixture grading high temperature performance advantages and disadvantages, ratio of filler to bitumen and dynamic stability, shear strength, creep slope has a good correlation, and asphalt film thickness and its correlation is poor. So suggest using dynamic stability and humbug wheel tracking creep slope, rutting depth combination evaluation mixture at high temperature performance advantages and disadvantages.

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