Network modelling of dry-type transformer cooling systems

2018 ◽  
Vol 37 (3) ◽  
pp. 1039-1053 ◽  
Author(s):  
Andrea Cremasco ◽  
Wei Wu ◽  
Andreas Blaszczyk ◽  
Bogdan Cranganu-Cretu
Keyword(s):  
Network Model ◽  
Thermal Model ◽  
Cfd Simulation ◽  
Cooling System ◽  
Cfd Simulations ◽  
Network Modelling ◽  
Cooling Systems ◽  
Content Type ◽  
System Configurations ◽  
Dielectric Insulation

Purpose The application of dry-type transformers is growing in the market because the technology is non-flammable, safer and environmentally friendly. However, the unit dimensions are normally larger and material costs become higher, as no oil is present for dielectric insulation or cooling. At designing stage, a transformer thermal model used for predicting temperature rise is fundamental and the modelling of cooling system is particularly important. This paper aims to describe a thermal model used to compute dry transformers with different cooling system configurations. Design/methodology/approach The paper introduces a fast-calculating thermal and pressure network model for dry-transformer cooling systems, preliminarily verified by analytical methods and advanced CFD simulations, and finally validated with experimental results. Findings This paper provides an overview of the network model of dry-transformer cooling system, describing its topology and its main variants including natural or forced ventilation, with or without cooling duct in the core, enclosure with roof and floor ventilation openings and air barriers. Finally, it presents a formulation for the new heat exchanger element. Originality/value The network approach presented in this paper allows to model efficiently the cooling system of dry-type transformers. This model is based on physical principles rather than empirical assessments that are valid only for specific transformer technologies. In comparison with CFD simulation approach, the network model runs much faster and the accuracies still fall in acceptable range; therefore, one is able to utilize this method in optimization procedures included in transformer design systems.

Influence of selected factors on parameters of a cooling system with a Peltier module and forced air flow

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Krzysztof Posobkiewicz ◽  
Krzysztof Górecki
Keyword(s):  
Thermal Resistance ◽  
Heat Sink ◽  
Cooling System ◽  
Heat Sinks ◽  
Cooling Power ◽  
Cooling Systems ◽  
Content Type ◽  
Peltier Module ◽  
Peltier Modules ◽  
Forced Air

Purpose The purpose of this study is to investigate the validation of the usefulness of cooling systems containing Peltier modules for cooling power devices based on measurements of the influence of selected factors on the value of thermal resistance of such a cooling system. Design/methodology/approach A cooling system containing a heat-sink, a Peltier module and a fan was built by the authors and the measurements of temperatures and thermal resistance in various supply conditions of the Peltier module and the fan were carried out and discussed. Findings Conclusions from the research carried out answer the question if the use of Peltier modules in active cooling systems provides any benefits comparing with cooling systems containing just passive heat-sinks or conventional active heat-sinks constructed of a heat-sink and a fan. Research limitations/implications The research carried out is the preliminary stage to asses if a compact thermal model of the investigated cooling system can be formulated. Originality/value In the paper, the original results of measurements and calculations of parameters of a cooling system containing a Peltier module and an active heat-sink are presented and discussed. An influence of power dissipated in the components of the cooling system on its efficiency is investigated.

CFD simulation of empty fuel tanks separation from a trainer jet

2020 ◽  
Vol 92 (10) ◽  
pp. 1459-1468
Author(s):  
Aleksander Olejnik ◽  
Adam Dziubiński ◽  
Łukasz Kiszkowiak
Keyword(s):  
Cfd Simulation ◽  
Body Movement ◽  
Cfd Simulations ◽  
Content Type ◽  
Sequential Release ◽  
Wind Tunnel Data ◽  
Computational Fluid Dynamics Cfd ◽  
External Forces ◽  
Additional Value ◽  
Control Surfaces

Purpose This study aims to create 6-degree of freedom (SDOF) for computational fluid dynamics (CFD) simulations of body movement, and to validate using the experimental data for empty tank separation from I-22 Iryda jet trainer. The procedure has an ability to be modified or extended, to simulate, for example, a sequential release from the joints. Design/methodology/approach A set of CFD simulations are calculated. Both the SDOF procedure and the CFD simulation settings are validated using the wind tunnel data available for the aircraft. Findings The simulation using designed procedure gives predictable results, but offers availability to be modified to represent external forces, i.e. from body interaction or control system without necessity to model the control surfaces. Practical implications The procedure could be used to model the separation of external stores and design the deployment of anti-radar chaff, flares or ejection seats. Originality/value The work presents original work, caused by insufficient abilities of original SDOF procedure in ANSYS code. Additional value is the ability of the procedure to be easily modified.

Performance Analysis With Future Predictions of Different Solar Cooling Systems in Guayaquil, Ecuador

2014 ◽  
Author(s):  
Carlos Naranjo-Mendoza ◽  
Jesús López-Villada ◽  
Gabriel Gaona ◽  
Jerko Labus
Keyword(s):  
Flow Rate ◽  
Cooling System ◽  
Meteorological Data ◽  
Cooling Systems ◽  
Great Opportunity ◽  
Constant Flow Rate ◽  
Solar Cooling ◽  
Average Annual Temperature ◽  
System Configurations

This paper presents a comparative analysis of three different solar cooling system configurations developed for a case study building in Guayaquil, Ecuador. Guayaquil is a city located at the Ecuadorian coast with an average annual temperature of 25°C. The city’s need for air conditioning throughout the year and the relatively intense solar radiation provide a great opportunity for implementation of solar cooling systems. The first cooling system includes a 175 kWc single-effect absorption chiller powered by evacuated tubes solar thermal collectors. This system was compared with two 140 kWc compression chiller systems (air-cooled (AC) and water-cooled (WC)) powered by grid-connected photovoltaics. Both constant flow rate (CFR) and variable flow rate (VFR) of chilled water were analyzed. The three systems have to satisfy a cooling demand of the top floor in one governmental building (app. 1296 m2) which was selected as case study. Additionally, two 140 kWc conventional compression chiller systems (AC and WC) were included in the comparison as reference systems. Cooling demand of the building was simulated in EnergyPlus and coupled with the appropriate system configurations developed in TRNSYS. The weather file (TMY) was developed based on real meteorological data collected in the last decade. The present analysis was extended with the prediction scenarios for the years 2020, 2050 and 2080 using climate change adapted weather files.

Market orientation and performance: modelling a neural network

2009 ◽  
Vol 43 (3/4) ◽  
pp. 421-437 ◽  
Author(s):  
Manuela Silva ◽  
Luiz Moutinho ◽  
Arnaldo Coelho ◽  
Alzira Marques
Keyword(s):  
Neural Network ◽  
Market Orientation ◽  
Network Model ◽  
Neural Network Model ◽  
Performance Modelling ◽  
Network Modelling ◽  
Content Type ◽  
Market Intelligence ◽  
And Performance ◽  
The Impact

PurposeThis paper aims to investigate the impact of market orientation (MO) on performance using a neural network model in order to find new linkages and new explanations for this relationship.Design/methodology/approachThis investigation is based on a survey data collection from a sample of 192 Portuguese companies. A neural network model has been developed to identify the effects of each dimension of MO on each dimension of performance.FindingsRelationship among MO and performance was corroborated but MO's impact is poor and based on its first dimension, market intelligence generation.Research limitations/implicationsFurther research in this field should be conducted using other tools offered by neural network modelling.Practical implicationsManagers should give more attention to cross‐functional co‐ordination in order to improve market intelligence dissemination and responsiveness and, thus, global performance.Originality/valueThe paper presents the development of a neural network model to analyse this relationship.

Three Dimensional CFD Simulation of Condensation Inside Inclined Tubes

2017 ◽  
Author(s):  
Amirhosein Moonesi Shabestary ◽  
Eckhard Krepper ◽  
Dirk Lucas ◽  
Thomas Höhne
Keyword(s):  
Heat Transfer ◽  
Annular Flow ◽  
Cfd Simulation ◽  
Cooling System ◽  
Heat Removal ◽  
Normal Operation ◽  
Cooling Systems ◽  
Horizontal Pipes ◽  
Subcooled Water ◽  
Operation Conditions

The current paper comprises CFD-modelling and simulation of condensation and heat transfer inside horizontal pipes. Designs of future nuclear boiling water reactor concepts are equipped with emergency cooling systems which are passive systems for heat removal. The emergency cooling system consists of slightly inclined horizontal pipes which are immersed in a tank of subcooled water. At normal operation conditions, the pipes are filled with water and no heat transfer to the secondary side of the condenser occurs. In the case of an accident the water level in the core is decreasing, steam comes in the emergency pipes and due to the subcooled water around the pipe, this steam will condense. The emergency condenser acts as a strong heat sink which is responsible for a quick depressurization of the reactor core when any accident happens. The actual project is defined in order to model all these processes which happen in the emergency cooling systems. The most focus of the project is on detection of different morphologies such as annular flow, stratified flow, slug flow and plug flow. The first step is the investigation of condensation inside a horizontal tube by considering the direct contact condensation (DCC). Therefore, at the inlet of the pipe an annular flow is assumed. In this step, the Algebraic Interfacial Area Density (AIAD) model is used in order to simulate the interface. The second step is the extension of the model to consider wall condensation effect as well which is closer to the reality. In this step, the inlet is pure steam and due to the wall condensation, a liquid film occurs near the wall which leads to annular flow. The last step will be modelling of different morphologies which are occurring inside the tube during the condensation via using the Generalized Two-Phase Flow (GENTOP) model extended by heat and mass transfer. By using GENTOP the dispersed phase is able to be considered and simulated. Finally, the results of the simulations will be validated by experimental data which will be available in HZDR. In this paper the results of the first part has been presented.

scholarly journals Performance improvement of an industrial control enclosure cooling system

2021 ◽  
pp. 177-177
Author(s):  
Wei-Ming Chiang ◽  
Fu-Jen Wang ◽  
K Kusnandar
Keyword(s):  
Heat Dissipation ◽  
Cfd Simulation ◽  
Cooling System ◽  
Flow Distribution ◽  
Field Measurements ◽  
Critical Issue ◽  
Industrial Control ◽  
Cooling Systems ◽  
Auxiliary Circulation ◽  
Air Vent

Following the trend of high-accuracy machining, thermal management of industrial control enclosures become a critical issue. Therefore, a well-designed enclosure cooling system is essential to manage the heat generation inside the enclosure. In this study, to improve the performance of cooling system and the air flow distribution inside the enclosure, computational fluid dynamics (CFD) simulation has been used to evaluate the application of using the auxiliary circulation fan and air baffler. Furthermore, this study also investigates the layout design for both supply air vent and return air vent arrangement by two types of commercialized cooling systems through field measurements. The simulation results show the short circulation of airflow is improved when the air baffler is installed. It also shows that the auxiliary circulation fan is suggested. Besides, air baffler is used to enhance the temperature distribution. The experimental results reveal the upper supply vent arrangement will cause the short circulation of airflow slightly. And, the auxiliary circulation fans can improve the heat dissipation of cooling systems. There is no short circulation of airflow for the lower supply vent arrangement, but the supply air cannot be distributed smoothly by the auxiliary circulation fans because the shape of the air baffler is not properly designed.

Three-dimensional CFD simulation and experimental validation of particle segregation in CFB riser

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Krishna Kant Dwivedi ◽  
Achintya Kumar Pramanick ◽  
Malay Kumar Karmakar ◽  
Pradip Kumar Chatterjee
Keyword(s):  
Fluidized Bed ◽  
Experimental Validation ◽  
Cfd Simulation ◽  
Particle Flow ◽  
Experimental Investigations ◽  
Gas Velocity ◽  
Particle Segregation ◽  
Cfd Simulations ◽  
Content Type ◽  
Drag Models

Purpose The purpose of this paper is to perform the computational fluid dynamics (CFD) simulation with experimental validation to investigate the particle segregation effect in abrupt and smooth shapes circulating fluidized bed (CFB) risers. Design/methodology/approach The experimental investigations were carried out in lab-scale CFB systems and the CFD simulations were performed by using commercial software BARRACUDA. Special attention was paid to investigate the gas-particle flow behavior at the top of the riser with three different superficial velocities, namely, 4, 6 and 7.7 m/s. Here, a CFD-based noble simulation approach called multi-phase particle in cell (MP-PIC) was used to investigate the effect of traditional drag models (Wen-Yu, Ergun, Wen-Yu-Ergun and Richardson-Davidson-Harrison) on particle flow characteristics in CFB riser. Findings Findings from the experimentations revealed that the increase in gas velocity leads to decrease the mixing index inside the riser. Moreover, the solid holdup found more in abrupt riser than smooth riser at the constant gas velocity. Despite the more experimental investigations, the findings with CFD simulations revealed that the MP-PIC approach, which was combined with different drag models could be more effective for the practical (industrial) design of CFB riser. Well agreement was found between the simulation and experimental outputs. The simulation work was compared with experimental data, which shows the good agreement (<4%). Originality/value The experimental and simulation study performed in this research study constitutes an easy-to-use with different drag coefficient. The proposed MP-PIC model is more effective for large particles fluidized bed, which can be helpful for further research on industrial gas-particle fluidized bed reactors. This study is expected to give throughout the analysis of CFB hydrodynamics with further exploration of overall fluidization.

scholarly journals Simplified Building Thermal Model Used for Optimal Control of Radiant Cooling System

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Lei He ◽  
Bo Lei ◽  
Haiquan Bi ◽  
Tao Yu
Keyword(s):  
Supervisory Control ◽  
Thermal Model ◽  
Thermal Environment ◽  
Cooling System ◽  
Hvac Systems ◽  
Cooling Load ◽  
System Operation ◽  
Cooling Systems ◽  
Radiant Cooling ◽  
Cooling Loads

MPC has the ability to optimize the system operation parameters for energy conservation. Recently, it has been used in HVAC systems for saving energy, but there are very few applications in radiant cooling systems. To implement MPC in buildings with radiant terminals, the predictions of cooling load and thermal environment are indispensable. In this paper, a simplified thermal model is proposed for predicting cooling load and thermal environment in buildings with radiant floor. In this thermal model, the black-box model is introduced to derive the incident solar radiation, while the genetic algorithm is utilized to identify the parameters of the thermal model. In order to further validate this simplified thermal model, simulated results from TRNSYS are compared with those from this model and the deviation is evaluated based on coefficient of variation of root mean square (CV). The results show that the simplified model can predict the operative temperature with a CV lower than 1% and predict cooling loads with a CV lower than 10%. For the purpose of supervisory control in HVAC systems, this simplified RC thermal model has an acceptable accuracy and can be used for further MPC in buildings with radiation terminals.

Assessment of the solar cooling technologies using analytical hierarchical process

2017 ◽  
Vol 14 (1) ◽  
pp. 84-90
Author(s):  
Muhammad Usman ◽  
Qazi Shehzad Ali ◽  
Muhammed Bilal
Keyword(s):  
Renewable Energy ◽  
Fossil Fuels ◽  
Cooling System ◽  
Renewable Energy Resources ◽  
Analytical Hierarchical Process ◽  
Cooling Systems ◽  
Content Type ◽  
Solar Cooling ◽  
Vapour Adsorption ◽  
Adsorption Cooling System

Purpose Decreasing sources of fossil fuels has caused an increase in importance of the renewable energy resources and systems that directly utilize renewable energy are even more important. The purpose of the paper is to compare the most common solar cooling technologies against the most important requirements. Design/methodology/approach A multi-criteria decision methodology, analytical hierarchical process, has been used to prioritize these technologies with respect to each other. Findings The findings of this study are the priorities of selected solar cooling concepts against performance affecting criteria. The solar vapour adsorption cooling system has been found to be the optimum solar cooling concept with practically the highest performance number compared with the other cooling systems. Originality/value This study can be used in the future development of solar cooling technologies to benefit from the best collective features of the specific technologies.

Assessment of thermal behavior of a cooling system to reduce thermal fatigue cracks in aluminum injection molds

2020 ◽  
pp. 75-86
Author(s):  
Sergio Antonio Camargo ◽  
Lauro Correa Romeiro ◽  
Carlos Alberto Mendes Moraes
Keyword(s):  
Thermal Fatigue ◽  
Cooling System ◽  
Fatigue Cracks ◽  
Cooling Water ◽  
Thermal Conditions ◽  
Thermal Gradients ◽  
Ansys Software ◽  
Cooling Systems ◽  
Thermal Fatigue Cracks ◽  
Number Of Cycles

The present article aimed to test changes in cooling water temperatures of males, present in aluminum injection molds, to reduce failures due to thermal fatigue. In order to carry out this work, cooling systems were studied, including their geometries, thermal gradients and the expected theoretical durability in relation to fatigue failure. The cooling system tests were developed with the aid of simulations in the ANSYS software and with fatigue calculations, using the method of Goodman. The study of the cooling system included its geometries, flow and temperature of this fluid. The results pointed to a significant increase in fatigue life of the mold component for the thermal conditions that were proposed, with a significant increase in the number of cycles, to happen failures due to thermal fatigue.

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