scholarly journals Heat Transfer in the Ducts of the Cooling Systems of Traction Motors

2018 ◽  
Vol 7 (4.3) ◽  
pp. 315
Author(s):  
A А. Aleksahin ◽  
A V Panchu ◽  
L A. Parkhomenko ◽  
H V. Bilovol
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Nuclear Power ◽  
Power Plants ◽  
Cooling System ◽  
Transfer Processes ◽  
New Energy ◽  
Working Media ◽  
Artificial Heat ◽  
The Impact

Requirements for increasing thermal efficiency heat exchangers, which lead to energy saving, material and reduction cost, and as a result of reducing the impact on the environment, led to the development and use of various methods of increasing heat transfer. These methods are called intensification of heat transfer processes. Intensification of heat and mass transfer processes is of great importance for making progress in improving the existing and creation of new energy and heat-exchange equipment. Among the ways of intensifying heat transfer, the swirling of flows of working media is one of the simplest and most common methods and is widely used in energy-intensive channels of nuclear power plants, heat exchangers, aeronautical and rocket and space equipment, chemical industry and other technical devices. We have proposed formulas to determine the cooling air velocity necessary to ensure the required temperature condition of the traction motor assemblies. Decrease in the power of fans in the cooling system using the artificial heat transfer intensification in the ducts was estimated based on the generalization of the results of calculations.  

THE THERMAL MODE OF LARGE-SPAN EXCA VATIONS DURING THE CONSTRUCTION OF NUCLEAR POWER FACILITIES

2020 ◽  
Vol 2 (1) ◽  
pp. 289-301
Author(s):  
I.P. KARNACHEV ◽  
◽  
V.G. NIKOLAEV ◽  
V.V. BIRYUKOV ◽  
S.A. GUSAK ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Mathematical Models ◽  
Experimental Research ◽  
Nuclear Power ◽  
Power Plants ◽  
Phase Transfer ◽  
Thermal Mode ◽  
Large Span ◽  
Transfer Processes

The paper observes particular experimental research results on increase of stability of mining excavations in a permafrost area under low positive temperatures. The authors discuss the tasks on determining the temperature field parameters around the different-section excavations of underground small nuclear power plants at the construction stage. The mathematical models were designed for heat transfer processes in frozen rocks. The rocks were simulated as pore media filled with water with phase transfer under heating. This allowed creating virtual computing stands on which it became possible to work out the thermal modes of excavation driving.

Development and Application of a Plugging Margin Evaluation Method Taking Into Account the Fouling of Shell-and-Tube Heat Exchangers

2005 ◽  
Author(s):  
Kyeong Mo Hwang ◽  
Tae Eun Jin
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Thermal Performance ◽  
Heat Exchangers ◽  
Nuclear Power ◽  
Power Plants ◽  
Evaluation Method ◽  
Operating Time ◽  
Flow Characteristics ◽  
Shell And Tube

As the operating time of heat exchangers progresses, fouling caused by water-borne deposits and the number of plugged tubes increase and thermal performance decreases. Both fouling and tube plugging are known to interfere with normal flow characteristics and to reduce thermal efficiencies of heat exchangers. The heat exchangers of Korean nuclear power plants have been analyzed in terms of heat transfer rate and overall heat transfer coefficient as a means of heat exchanger management. Except for fouling resulting from the operation of heat exchangers, all the tubes of heat exchangers have been replaced when the number of plugged tubes exceeded the plugging criteria based on design performance sheet. This paper describes a plugging margin evaluation method taking into account the fouling of shell-and-tube heat exchangers. The method can evaluate thermal performance, estimate future fouling variation, and consider current fouling level in the calculation of plugging margin. To identify the effectiveness of the developed method, fouling and plugging margin evaluations were performed at a component cooling heat exchanger in a Korean nuclear power plant.

Mini-Channel Supercritical CO2 Heat Transfer Measurements for Brayton Cycle Regenerators

2009 ◽  
Author(s):  
Alan Kruizenga ◽  
Mark Anderson ◽  
Michael Corradini
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Critical Point ◽  
Heat Exchangers ◽  
Nuclear Power ◽  
Power Plants ◽  
Effective Length ◽  
Transfer Coefficients ◽  
Capital Costs ◽  
Mini Channels

Recently, it has become increasingly important to improve efficiency and reduce capital costs in nuclear power plants. This prompted significant work in studying advanced Brayton cycles for high temperature energy conversion. A particular improvement in the operation of an advanced carbon dioxide cycle, is the use of compact, highly efficient, diffusion bonded heat exchangers for the recuperators. These heat exchangers operate near the pseudo-critical point of liquid carbon dioxide, making use of the drastic variation of the thermo-physical properties. This paper focuses on the experimental measurements of heat transfer and pressure drop characteristics within mini-channels. Two test section channel geometries are studied: a straight channel and a zig-zag channel. Both configurations are 0.5m in length and constructed out of 316 stainless steel with a series of nine parallel 1.9mm semi-circular channels. The zig-zag configuration has an angle of 115 degrees with an effective length of ∼0.58m. Heat transfer measurements are conducted for varying ranges of inlet temperatures, pressures, and mass flow rates. Local and average heat transfer coefficients near the critical point are determined from measured wall temperatures and calculated local bulk temperatures.

scholarly journals Heat Pipe as a Passive Cooling System Driving New Generation of Nuclear Power Plants

2021 ◽  
pp. 30-38
Author(s):  
Ziba Zibandeh Nezam ◽  
Bahman Zohuri
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Nuclear Power ◽  
Power Plants ◽  
Cooling System ◽  
Heat Pipes ◽  
Passive Cooling ◽  
Nuclear Power Reactor ◽  
Pipe System ◽  
New Generation

The technology of the Heat Pipe (HP) system is very well known for scientists and engineers working in the field of thermal-hydraulic since its invention at Las Alamos Nation Laboratory around the 1960s time frame. It is a passive heat transfer/heat exchanger system that comes in the form of either a constant or variable system without any mechanical built-in moving part. This passive heat transfer system and its augmentation within the core of nuclear power reactors have been proposed in the past few decades. The sodium, potassium, or mercury type heat pipe system using any of these three elements for the cooling system has been considered by many manufacturers of fission reactors and recently fusion reactors particularly Magnetic Confinement Fusion (MCF). Integration of the heat pipes as passive cooling can be seen in a new generation of a nuclear power reactor system that is designed for unconventional application field such as a space-based vehicle for deep space or galaxy exploration, planetary surface-based power plants as well as operation in remote areas on Earth. With the new generation of Small Modular Reactor (SMR) in form of Nuclear Micro Reactors (NMR), this type of fission reactor has integrated Alkali metal heat pipes to a series of Stirling convertors or thermoelectric converters for power generation that would generate anywhere from 13kwt to 3Mwt thermal of power for the energy conversion system.

scholarly journals Optimization of heat transfer processes in the circuit of a nuclear power plant in order to increase it

2021 ◽  
Vol 3 (134) ◽  
pp. 79-86
Author(s):  
Svetlana Shvachich ◽  
Vladimir Bulychev ◽  
Kateryna Ternova
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Heat Exchangers ◽  
Nuclear Power ◽  
Nuclear Energy ◽  
Secondary Circuit ◽  
Transfer Processes ◽  
Heat Carriers

The urgency of the work is due to the depletion of traditional fuel reserves and increasing the load on the biosphere because of emissions from burning coal, oil and gas. The solution of these problems are the development of nuclear energy. The advantages of nuclear energy are analyzed, namely: high calorific value of nuclear fuel, better economic indicators, less environmental pollution. The purpose of this work is to optimize the heat transfer processes in the secondary circuit of a nuclear power plant. It is proposed to take the second circuit of the third power unit of the Rivne nuclear power plant as the object of research. The need for knowledge of heat transfer processes and hydrodynamics is determined by the fact that nuclear reactors are energy-intensive thermal machines, in which these processes are manifested in a rather complex form. Therefore, measures to optimize heat transfer processes in the thermal circuit of the second circuit of the NPP in order to increase energy performance are considered. In order to remove from the system the hardness salts that settle on the walls of the equipment and impair the heat transfer processes, a reagent has been selected to bind the hardness salts. he addition of the PuroTech113 reagent to the working circuit of the secondary circuit made it possible to free the system from the deposition of hardness salts in it, as this reagent "binds" free calcium and magnesium ions. In turn, scale is no longer deposited on the walls of the heat exchange equipment, which allows to fully transferring the required amount of heat. Recalculation of the thermal balance showed that the efficiency of the unit is increased by 3%.The efficiency coefficient of the heat exchanger was chosen as the criterion of optimality. The efficiency of the heat exchanger in the general case is a function of the mode parameters, the scheme of mutual movement of heat carriers and features of hydrodynamics and heat transfer of real heat exchangers. The problem of optimizing the movement of heat carriers in intermediate heat exchangers is solved in paper.

Human reliability in non-destructive inspections of nuclear power plant components: modeling and analysis

2019 ◽  
Vol 7 (2B) ◽  
Author(s):  
Vanderley Vasconcelos ◽  
Wellington Antonio Soares ◽  
Raissa Oliveira Marques ◽  
Silvério Ferreira Silva Jr ◽  
Amanda Laureano Raso
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Human Factors ◽  
Nuclear Power ◽  
Power Plants ◽  
Failure Modes ◽  
Cooling System ◽  
Human Reliability ◽  
Non Destructive ◽  
Plant Components

Non-destructive inspection (NDI) is one of the key elements in ensuring quality of engineering systems and their safe use. This inspection is a very complex task, during which the inspectors have to rely on their sensory, perceptual, cognitive, and motor skills. It requires high vigilance once it is often carried out on large components, over a long period of time, and in hostile environments and restriction of workplace. A successful NDI requires careful planning, choice of appropriate NDI methods and inspection procedures, as well as qualified and trained inspection personnel. A failure of NDI to detect critical defects in safety-related components of nuclear power plants, for instance, may lead to catastrophic consequences for workers, public and environment. Therefore, ensuring that NDI is reliable and capable of detecting all critical defects is of utmost importance. Despite increased use of automation in NDI, human inspectors, and thus human factors, still play an important role in NDI reliability. Human reliability is the probability of humans conducting specific tasks with satisfactory performance. Many techniques are suitable for modeling and analyzing human reliability in NDI of nuclear power plant components, such as FMEA (Failure Modes and Effects Analysis) and THERP (Technique for Human Error Rate Prediction). An example by using qualitative and quantitative assessesments with these two techniques to improve typical NDI of pipe segments of a core cooling system of a nuclear power plant, through acting on human factors issues, is presented.

MODELLING AND SIMULATION OF HEAT TRANSFER PROCESSES FOR HEAT EXCHANGERS USED IN WASTEWATER TREATMENT

2016 ◽  
Vol 15 (5) ◽  
pp. 1027-1033 ◽  
Author(s):  
Timea Gabor ◽  
Viorel Dan ◽  
Ancuta Elena Tiuc ◽  
Ioana Monica Sur ◽  
Iulian Nicolae Badila
Keyword(s):  
Heat Transfer ◽  
Wastewater Treatment ◽  
Heat Exchangers ◽  
Modelling And Simulation ◽  
Transfer Processes

scholarly journals Efficiency Improvement of Miniaturized Heat Exchangers

Fluids ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 25
Author(s):  
Iris Gerken ◽  
Thomas Wetzel ◽  
Jürgen J. Brandner
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Heat Exchangers ◽  
Assessment Method ◽  
Flow Path ◽  
Transfer Enhancement ◽  
Pressure Losses ◽  
Pin Fin ◽  
Additional Pressure ◽  
The Impact

Micro heat exchangers have been revealed to be efficient devices for improved heat transfer due to short heat transfer distances and increased surface-to-volume ratios. Further augmentation of the heat transfer behaviour within microstructured devices can be achieved with heat transfer enhancement techniques, and more precisely for this study, with passive enhancement techniques. Pin fin geometries influence the flow path and, therefore, were chosen as the option for further improvement of the heat transfer performance. The augmentation of heat transfer with micro heat exchangers was performed with the consideration of an improved heat transfer behaviour, and with additional pressure losses due to the change of flow path (pin fin geometries). To capture the impact of the heat transfer, as well as the impact of additional pressure losses, an assessment method should be considered. The overall exergy loss method can be applied to micro heat exchangers, and serves as a simple assessment for characterization. Experimental investigations with micro heat exchanger structures were performed to evaluate the assessment method and its importance. The heat transfer enhancement was experimentally investigated with microstructured pin fin geometries to understand the impact on pressure loss behaviour with air.

Design and testing of energy-efficient heat exchangers for Newtonian and non-Newtonian fluids – A review

2021 ◽  
pp. 095765092110470
Author(s):  
Jayesh P ◽  
Mukkamala Y ◽  
Bibin John
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Heat Exchangers ◽  
Internal Surface ◽  
Surface Modifications ◽  
Newtonian Fluids ◽  
Tube Surface ◽  
Pumping Power ◽  
Transfer Enhancement ◽  
The Impact

Heat transfer enhancement, pumping power and weight minimization in enhanced heat exchangers has long been achieved by deploying tubes with internal surface modifications like microgrooves, ribs, fins, knurls, and dimples with and without tube inserts. This article presents a very extensive review of experimental and computational studies on heat transfer enhancement, which covers convectional and unconventional working fluids under different fluid flow conditions. Compound augmentation with tube surface modifications and inserts has yielded enhancements in the overall heat transfer coefficient of over 116% in the fully developed turbulent flow regime. Exotic fluids like nano-coolants deployed in spiral grooved mircofin tubes yielded 196% enhancement in tube side heat transfer rate for concentrations as low as 0.5% by volume, while the thermal efficiency index measuring the overall enhancement in relation to the pumping power was 75%. However, reviews that address the combined effect of unconventional fluids, surface modifications and tube inserts on the overall thermo-hydraulic performance of annular heat exchangers seem to be limited. Further, nano-coolants aren’t frequently used in the process industry. The goal of this study is to document and evaluate the impact of cost-effective and energy-saving passive enhancement techniques such as tube surface modifications, tube inserts, and annular enhancement techniques on annular heat exchangers used in the process industries with Newtonian and non-Newtonian fluids. This review should be useful to engineers, academics and medical professionals working with non-Newtonian fluids and enhanced heat exchangers.

RevospECT® PRO Software for Automated Interpretation of Results and Automatic Tracking of Defects during Eddy Current Inspection of Heat Exchangers

NDT World ◽  
2021 ◽  
pp. 21-23
Author(s):  
Denis Shorikov ◽  
Aleksandra Melnikova
Keyword(s):  
Eddy Current ◽  
Heat Exchangers ◽  
Nuclear Power ◽  
Power Plants ◽  
Level Ii ◽  
Unique System ◽  
Self Study ◽  
Software Product ◽  
Eddy Current Inspection ◽  
Automated Interpretation

The eddy current NDT method has been successfully used at Russian nuclear power plants for more than 20 years, but there are still problems with assessing the reliability of the results. Software product of Zetec Inc. (USA) RevospECT® Pro allows you to automatically analyze and compare the monitoring results of the same object, obtained at different times, which allows you to track the development of defects. Thanks to a unique system for collecting and analyzing information, its ability to self-study, RevospECT® Pro is able to make decisions on its own, replacing the level II specialist in full.

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