scholarly journals Microstructure-Based Lifetime Assessment of Austenitic Steel AISI 347 in View of Fatigue, Environmental Conditions and NDT

2021 ◽  
Vol 11 (23) ◽  
pp. 11214
Author(s):  
Ruth Acosta ◽  
Klaus Heckmann ◽  
Jürgen Sievers ◽  
Tim Schopf ◽  
Tobias Bill ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Power Plants ◽  
Microstructural Analysis ◽  
Fatigue Tests ◽  
Hot Water ◽  
Subsequent Paper ◽  
Thermal Transients ◽  
Lack Of Information ◽  
Lifetime Analysis ◽  
Materials Used

The assessment of metallic materials used in power plants’ piping represents a big challenge due to the thermal transients and the environmental conditions to which they are exposed. At present, a lack of information related to degradation mechanisms in structures and materials is covered by safety factors in its design, and in some cases, the replacement of components is prescribed after a determined period of time without knowledge of the true degree of degradation. In the collaborative project “Microstructure-based assessment of maximum service life of nuclear materials and components exposed to corrosion and fatigue (MibaLeb)”, a methodology for the assessment of materials’ degradation is being developed, which combines the use of NDT techniques for materials characterization, an optimized fatigue lifetime analysis using short time evaluation procedures (STEPs) and numerical simulations. In this investigation, the AISI 347 (X6CrNiNb18-10) is being analyzed at different conditions in order to validate the methodology. Besides microstructural analysis, tensile and fatigue tests, all to characterize the material, a pressurized hot water pipe exposed to a series of flow conditions will be evaluated in terms of full-scale testing as well as prognostic evaluation, where the latter will be based on the materials’ data generated, which should prognose changes in the material’s condition, specifically in a pre-cracked stage. This paper provides an overview of the program, while the more material’s related aspects are presented in the subsequent paper.

scholarly journals Interaction between Biofilm Formation, Surface Material and Cleanability Considering Different Materials Used in Pig Facilities—An Overview

2021 ◽  
Vol 13 (11) ◽  
pp. 5836
Author(s):  
Erika Yukari Nakanishi ◽  
Joahnn H. Palacios ◽  
Stéphane Godbout ◽  
Sébastien Fournel
Keyword(s):  
Complex System ◽  
Environmental Conditions ◽  
Biofilm Formation ◽  
Hot Water ◽  
Surface Material ◽  
Chemical Treatments ◽  
Disinfection Procedure ◽  
Main Factors ◽  
Materials Used ◽  
Cleaning And Disinfection

Sometimes the contamination in pig facilities can persist even after the washing and disinfection procedure. Some factors could influence this persistence, such as bacteria type, biofilm formation, material type and washing parameters. Therefore, this review summarizes how the type of surface can influence bacteria colonization and how the washing procedure can impact sanitary aspects, considering the different materials used in pig facilities. Studies have shown that biofilm formation on the surface of different materials is a complex system influenced by environmental conditions and the characteristics of each material’s surface and group of bacteria. These parameters, along with the washing parameters, are the main factors having an impact on the removal or persistence of biofilm in pig facilities even after the cleaning and disinfection processes. Some options are available for proper removal of biofilms, such as chemical treatments (i.e., detergent application), the use of hot water (which is indicated for some materials) and a longer washing time.

Fracture Behavior of Ceramics Used in Multilayer Capacitors

1986 ◽  
Vol 72 ◽  
Author(s):  
Theresa L. Baker ◽  
Stephen W. Freiman
Keyword(s):  
Crack Growth ◽  
Fracture Behavior ◽  
Ceramic Materials ◽  
Fatigue Tests ◽  
Internal Stresses ◽  
Crack Growth Behavior ◽  
Multilayer Capacitors ◽  
Materials Used ◽  
Aging Phenomena

AbstractThis study involved the determination of the effects of composition and microstructure on the fracture toughness and susceptibility to environmentally enhanced crack growth of several ceramic materials used in multilayer capacitors. Indentation-fracture procedures were used to measure KIC as well as to assess the possible effects of internal stresses on the fracture behavior of these materials and to correlate dielectric aging phenomena with strength. The environmentally enhanced crack growth behavior of these materials was determined by conducting dynamic fatigue tests in water.

Gigacycle Fatigue of Welded Joints of Structural Materials (A Review)

2016 ◽  
Vol 17 ◽  
pp. 14-30 ◽  
Author(s):  
Okechukwu P. Nwachukwu ◽  
Alexander V. Gridasov ◽  
Ekaterina A. Gridasova
Keyword(s):  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Testing Machine ◽  
Structural Materials ◽  
Fatigue Tests ◽  
Material Defects ◽  
Graphite Cast Iron ◽  
Ultrasonic Fatigue ◽  
Materials Used ◽  
Fatigue Failures

This review looks into the state of gigacycle fatigue behavior of some structural materials used in engineering works. Particular attention is given to the use of ultrasonic fatigue testing machine (USF-2000) due to its important role in conducting gigacycle fatigue tests. Gigacycle fatigue behavior of most materials used for very long life engineering applications is reviewed.Gigacycle fatigue behavior of magnesium alloys, aluminum alloys, titanium alloys, spheroid graphite cast iron, steels and nickel alloys are reviewed together with the examination of the most common material defects that initiate gigacycle fatigue failures in these materials. In addition, the stage-by-stage fatigue crack developments in the gigacycle regime are reviewed. This review is concluded by suggesting the directions for future works in gigacycle fatigue.

Development of 1500-r/min 75-Inch Ultra-Long Last Stage Blades for Nuclear Steam Turbine

2017 ◽  
Author(s):  
Deqi Yu ◽  
Jiandao Yang ◽  
Wei Lu ◽  
Daiwei Zhou ◽  
Kai Cheng ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Large Scale ◽  
Vibration Monitoring ◽  
Steam Turbines ◽  
Element Analysis ◽  
Rotating Blade ◽  
Lifetime Analysis ◽  
Computational Fluid Dynamics Cfd ◽  
Last Stage

The 1500-r/min 1905mm (75inch) ultra-long last three stage blades for half-speed large-scale nuclear steam turbines of 3rd generation nuclear power plants have been developed with the application of new design features and Computer-Aided-Engineering (CAE) technologies. The last stage rotating blade was designed with an integral shroud, snubber and fir-tree root. During operation, the adjacent blades are continuously coupled by the centrifugal force. It is designed that the adjacent shrouds and snubbers of each blade can provide additional structural damping to minimize the dynamic stress of the blade. In order to meet the blade development requirements, the quasi-3D aerodynamic method was used to obtain the preliminary flow path design for the last three stages in LP (Low-pressure) casing and the airfoil of last stage rotating blade was optimized as well to minimize its centrifugal stress. The latest CAE technologies and approaches of Computational Fluid Dynamics (CFD), Finite Element Analysis (FEA) and Fatigue Lifetime Analysis (FLA) were applied to analyze and optimize the aerodynamic performance and reliability behavior of the blade structure. The blade was well tuned to avoid any possible excitation and resonant vibration. The blades and test rotor have been manufactured and the rotating vibration test with the vibration monitoring had been carried out in the verification tests.

scholarly journals Investigation of Corrosion Resistance of Alloys with Potential Application in Supercritical Water-cooled Nuclear Reactors

2019 ◽  
Vol 63 (2) ◽  
pp. 328-332 ◽  
Author(s):  
Ákos Horváth ◽  
Attila R. Imre ◽  
György Jákli
Keyword(s):  
Corrosion Resistance ◽  
Supercritical Water ◽  
Power Plants ◽  
Fuel Cladding ◽  
Pressurized Water ◽  
Water Reactors ◽  
Reactor Types ◽  
Materials Used ◽  
Supercritical Water Cooled Reactor ◽  
Nuclear Applications

The Supercritical Water Cooled Reactor (SCWR) is one of the Generation IV reactor types, which has improved safety and economics, compared to the present fleet of pressurized water reactors. For nuclear applications, most of the traditional materials used for power plants are not applicable, therefore new types of materials have to be developed. For this purpose corrosion tests were designed and performed in a supercritical pressure autoclave in order to get data for the design of an in-pile high temperature and high-pressure corrosion loop. Here, we are presenting some results, related to corrosion resistance of some potential structural and fuel cladding materials.

scholarly journals MEASUREMENT OF THE EFFICIENCY OF EVACUATED TUBE SOLAR COLLECTORS UNDER VARIOUS OPERATING CONDITIONS

2012 ◽  
Vol 7 (3) ◽  
pp. 114-130 ◽  
Author(s):  
S. E. Zubriski ◽  
K. J. Dick
Keyword(s):  
Environmental Conditions ◽  
Operating Conditions ◽  
Hot Water ◽  
Heat Transfer Fluid ◽  
Operating Efficiency ◽  
Space Heating ◽  
Solar Collectors ◽  
Auxiliary Equipment ◽  
Evacuated Tubes ◽  
Evacuated Tube

The operating efficiency of evacuated tubes themselves under varying environmental conditions and installation scenarios, independent of water and space heating auxiliary equipment, are not readily available values. Further, Manitoba specific data has not been established. The purpose of this research program was to measure the efficiency of evacuated tube solar collectors under various operating conditions including: the angle of inclination towards the incident solar radiation, heat transfer fluid flow rate, glazing installation, and number of evacuated tubes. The operating conditions and configurations were chosen to represent realistic or probable installation scenarios and environmental conditions. Furthermore, the research aimed to identify the suitability of evacuated tube solar collectors to each of the scenarios. These design values are of use for appropriate sizing of water or space heating systems, system configuration and optimization, and calculation of return on investment. The scope of the research project was limited to the efficiency of various configurations of a 32-tube panel, not the entire solar domestic hot water or space heating system. Thus, factors such as heat loss in the tubing, solar storage tank, and heat exchanger efficiency were not investigated. The findings indicated that efficiency varied by approximately 5% between the different collector configurations, as observed from the overlay graph of results. When the efficiency of a collector is considered within a system it is proposed that effectiveness may be a better measure of overall performance.

scholarly journals A Project To Estimate The Power Capacity Of Geothermal Power Plants Based On The Enthalpy Of Geothermal Fluid And Plant Design

2021 ◽  
Author(s):  
Obumneme Oken
Keyword(s):  
Power Plant ◽  
Geothermal Energy ◽  
Electricity Generation ◽  
Power Plants ◽  
Hot Water ◽  
Power Capacity ◽  
Geothermal Fluid ◽  
Direct Heating ◽  
Single Flash ◽  
Geothermal Power

Nigeria has some surface phenomena that indicate the presence of viable geothermal energy. None of these locations have been explored extensively to determine the feasibility of sustainable geothermal energy development for electricity generation or direct heating. In this context, the present study aims to provide insight into the energy potential of such development based on the enthalpy estimation of geothermal reservoirs. This particular project was conducted to determine the amount of energy that can be gotten from a geothermal reservoir for electricity generation and direct heating based on the estimated enthalpy of the geothermal fluid. The process route chosen for this project is the single-flash geothermal power plant because of the temperature (180℃) and unique property of the geothermal fluid (a mixture of hot water and steam that exists as a liquid under high pressure). The Ikogosi warm spring in Ekiti State, Nigeria was chosen as the site location for this power plant. To support food security efforts in Africa, this project proposes the cascading of a hot water stream from the flash tank to serve direct heat purposes in agriculture for food preservation, before re-injection to the reservoir. The flowrate of the geothermal fluid to the flash separator was chosen as 3125 tonnes/hr. The power output from a single well using a single flash geothermal plant was evaluated to be 11.3 MW*. This result was obtained by applying basic thermodynamic principles, including material balance, energy balance, and enthalpy calculations. This particular project is a prelude to a robust model that will accurately determine the power capacity of geothermal power plants based on the enthalpy of fluid and different plant designs.

scholarly journals STUDY OF THE EFFECTIVENESS OF VIBRATION ISOLATION OF UNCONVENTIONAL TOROIDAL ROPE VIBRATION ISOLATORS IN DIESEL UNITS VIBRATION ISOLATION SYSTEM

Akustika ◽  
2019 ◽  
Vol 32 ◽  
pp. 110-114
Author(s):  
Minas Minasyan ◽  
Armen Minasyan ◽  
Aung Thant
Keyword(s):  
Power Plants ◽  
Vibration Isolation ◽  
Steel Wire ◽  
Experimental Studies ◽  
Wire Rope ◽  
Diesel Generator ◽  
Isolation System ◽  
Vibration Isolators ◽  
Before And After ◽  
Materials Used

The paper notes that the structure of the wire rope is one of the most suitable materials used as a fire-resistant elastic element of vibration-insulating structures and fasteners (vibration isolators). To solve the problems of vibration isolation of marine diesel power plants in the framework of development and improvement of the shock absorption system, the original patented elastic supports with elastic elements made of steel wire rope in the form of a torus are presented. When commercially available vibration isolators do not meet the relevant requirements of vibration protection of a particular object, the solution to the existing problem can be achieved by using the proposed wire rope vibration isolators. The technical results of the original patented inventions are: - equal stiffness in the horizontal plane - ensuring the reliability and high vibration efficiency of protection against impacts and shocks. The proposed designs of vibration isolators are easy (technological in manufacturing) to manufacture and assemble, reliable and durable - the service life is 10 years or more. Vibration efficiency is confirmed by the vibration acceleration spectra before and after the vibration isolator of the damping system of the ship diesel-generator DGA-500 and the diesel unit with a 2H 8.5/11 engine and water brake on a common sub-frame. The three-year trial life of the DGA-500 and experimental studies on a diesel unit with a 2H 8.5/11 engine and water brake on a common sub-frame confirms their efficiency and effectiveness.

Failure Investigation of Tubular Adhesive Dissimilar Joint

2015 ◽  
Vol 786 ◽  
pp. 43-47
Author(s):  
M. Faizi ◽  
W.M. Syafiq ◽  
M. Afendi ◽  
N.G. Chuen ◽  
Abu Bakar Shahriman
Keyword(s):  
Adhesive Joint ◽  
Failure Load ◽  
Testing Machine ◽  
Welding Process ◽  
Fatigue Tests ◽  
Failure Investigation ◽  
Lap Shear ◽  
Universal Testing ◽  
Shear Joint ◽  
Materials Used

Automotive industries are looking for new implementation to deliver a good finishing product to their customer. By using adhesive material, joining against two steel can replace normal technique which is welding process. However, the strength produced by this method must be investigated. The failure investigation of ductile adhesive intended for use in automotive tubular frame chassis has been assessed using simple tubular lap shear joint. There are two different overlap lengths of tubular adhesive joint considered in this test, i.e., 15 mm and 45 mm. The materials used for the adherents were stainless steel and mild steel, while adhesive used in the experiments was Araldite Standard 90 minutes epoxy resin. Tensile test by utilizing universal testing machine (UTM) was carried out to determine the shear strength of the adhesive joint in different overlap length. Fatigue tests were also conducted. From the results it is found that longer overlap length of the adhesive is preferable for use in automotive tubular frame chassis due to higher failure load it can withstand and better fatigue life.

scholarly journals Experimental Study on Effect of Water Spray Characteristics on Performance of Cooling Tower

2020 ◽  
Vol 170 ◽  
pp. 01009
Author(s):  
Akshay S. Dhurandhar ◽  
Amarsingh B. Kanase-Patil
Keyword(s):  
Power Plants ◽  
Cooling Tower ◽  
Thermal Power ◽  
Evaporative Cooling ◽  
Hot Water ◽  
Spray Angle ◽  
Counter Flow ◽  
Steam Power ◽  
To Come ◽  
Spiral Type

Cooling tower is an indispensable part, used as a direct contact type heat exchanger mainly for evaporative cooling. Cooling tower generally dissipates, remove heat from thermal power plants. In an induced draft cooling tower of counter flow, used for a mini-steam power plant, hot water enters at the top, while the air is introduced at the bottom and exits at the top, air is allowed to come in contact with falling water droplets, causing evaporative cooling. A possibility of desired change with different spray angle, patterns, is tried and analysed. On findings, best suited spray nozzle angle resulted is 90°, and amongst three spray patterns, full cone, hollow cone and spiral type nozzle; full cone nozzle of 90° spray angle helps achieving efficiency up to 82%. The range increases successively from 9.8°C to 15.5°C for FC nozzle, in approach to WBT; the desirable fall of 3.56°C is attained with effectiveness of 81.63%.

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