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Records with Keyword: Modelling
Showing records 51 to 75 of 402. [First] Page: 1 2 3 4 5 6 7 Last
Application of Regression and ANN Models for Heat Pumps with Field Measurements
Anjan Rao Puttige, Staffan Andersson, Ronny Östin, Thomas Olofsson
April 14, 2023 (v1)
Keywords: artificial neural network, field measurements, heat pump, Modelling, regression model
Developing accurate models is necessary to optimize the operation of heating systems. A large number of field measurements from monitored heat pumps have made it possible to evaluate different heat pump models and improve their accuracy. This study used measured data from a heating system consisting of three heat pumps to compare five regression and two artificial neural network (ANN) models. The models’ performance was compared to determine which model was suitable during the design and operation stage by calibrating them using data provided by the manufacturer and the measured data. A method to refine the ANN model was also presented. The results indicate that simple regression models are more suitable when only manufacturers’ data are available, while ANN models are more suited to utilize a large amount of measured data. The method to refine the ANN model is effective at increasing the accuracy of the model. The refined models have a relative root mean square error (RMSE) of less th... [more]
Influence of the Semiconductor Devices Cooling Conditions on Characteristics of Selected DC−DC Converters
Krzysztof Górecki
April 14, 2023 (v1)
Keywords: averaged models, DC–DC converters, diode-transistor switch, electrothermal models, Modelling, power semiconductor de vices, SPICE
The problem of an influence of cooling conditions of power semiconductor devices on properties of selected DC−DC converters is considered. The new version of electrothermal average model of a diode-transistor switch for SPICE (Simulation Program with Integrated Circuit Emphasis) is used in the investigations. This model makes it possible to take into account thermal inertia of semiconductor devices as well as mutual thermal interactions between these devices. The investigations are performed for boost and buck converters containing the power MOS (Metal-Oxide-Semiconductor) transistor and the diode. Computational results obtained using the proposed model are shown and discussed. Particularly, an influence of thermal phenomena in the diode and the power MOS transistor on the converters output voltage and internal temperature of the semiconductor devices is considered. The correctness of the selected results of computations was verified experimentally.
High Performance Electric Vehicle Powertrain Modeling, Simulation and Validation
Feyijimi Adegbohun, Annette von Jouanne, Ben Phillips, Emmanuel Agamloh, Alex Yokochi
April 14, 2023 (v1)
Keywords: chassis dynamometer, drive cycle, electric vehicle, Modelling
Accurate electric vehicle (EV) powertrain modeling, simulation and validation is paramount for critical design and control decisions in high performance vehicle designs. Described in this paper is a methodology for the design and development of EV powertrain through modeling, simulation and validation on a real-world vehicle system with detailed analysis of the results. Although simulation of EV powertrains in software simulation environments plays a significant role in the design and development of EVs, validating these models on the real-world vehicle systems plays an equally important role in improving the overall vehicle reliability, safety and performance. This modeling approach leverages the use of MATLAB/Simulink software for the modeling and simulation of an EV powertrain, augmented by simultaneously validating the modeling results on a real-world vehicle which is performance tested on a chassis dynamometer. The combination of these modeling techniques and real-world validation... [more]
Optimization of Thermal Backfill Configurations for Desired High-Voltage Power Cables Ampacity
Stanislaw Czapp, Filip Ratkowski
April 14, 2023 (v1)
Keywords: ampacity, economic optimization, high-voltage power cables, Modelling
The ampacity of high-voltage power cables depends, among others, on their core cross-sectional area as well as thermal resistivity of the thermal backfill surrounding the cables. The cross-sectional area of the power cables’ core is selected according to the expected power to be transferred via the cable system. Usually, the higher the power transfer required, the higher the cross-sectional area of the core. However, the cost of high-voltage power cables is relatively high and strictly depends on the dimensions of the core. Therefore, from the economic point of view, it is interesting to focus on the improvement of the thermal condition around the cables, by changing the dimension of the thermal backfill, instead of increasing the power cables’ core cross-sectional area. In practice, it is important to find the optimal dimensions of both cable core and thermal backfill to achieve the economically attractive solution of the power cable transfer system. This paper presents a mathematical... [more]
Complex Valuation of Energy from Agricultural Crops including Local Conditions
Václav Voltr, Martin Hruška, Luboš Nobilis
April 14, 2023 (v1)
Keywords: climate, energy crops, gross margin, LCA, local conditions, Modelling, soil
This paper provides values of economic, energy and environmental assessments of 20 crops and assesses the relationships of soil-climatic conditions in the example of the Czech Republic. The comparison of main soil quality indicators according to the configuration of land and climate regions is performed on the basis of energy and economic efficiency as well as a comparison of the level of environmental impacts. The environmental impacts are identified based on the assessment of emissions from production and also in the form of soil compaction as an indicator of the relationship to soil quality. As concerns soil properties, of major importance is soil skeleton, slope of land and the depth of soil, which cause an increase in emissions from the energy produced. Substantially better emission parameters per 1 MJ through energy crops, the cultivation of perennial crops and silage maize has been supported. Among energy crops, a positive relationship with the quality of soil is seen in alfalfa... [more]
Compact Modelling of Electrical, Optical and Thermal Properties of Multi-Colour Power LEDs Operating on a Common PCB
Krzysztof Górecki, Przemysław Ptak
April 14, 2023 (v1)
Subject: Other
Keywords: electro-thermal models, Modelling, multi-colour power LEDs, mutual thermal couplings, self-heating, SPICE, thermal phenomena
This paper concerns the problem of modelling electrical, thermal and optical properties of multi-colour power light-emitting diodes (LEDs) situated on a common PCB (Printed Circuit Board). A new form of electro-thermo-optical model of such power LEDs is proposed in the form of a subcircuit for SPICE (Simulation Program with Integrated Circuits Emphasis). With the use of this model, the currents and voltages of the considered devices, their junction temperature and selected radiometric parameters can be calculated, taking into account self-heating phenomena in each LED and mutual thermal couplings between each pair of the considered devices. The form of the formulated model is described, and a manner of parameter estimation is also proposed. The correctness and usefulness of the proposed model are verified experimentally for six power LEDs emitting light of different colours and mounted on an experimental PCB prepared by the producer of the investigated devices. Verification was perform... [more]
Modeling Stray Capacitances of High-Voltage Capacitive Dividers for Conventional Measurement Setups
Alessandro Mingotti, Federica Costa, Lorenzo Peretto, Roberto Tinarelli, Paolo Mazza
April 14, 2023 (v1)
Keywords: capacitive divider, capacitor, expressions, high voltage, Modelling, stray capacitance, voltage divider
Stray capacitances (SCs) are a serious issue in high-voltage (HV) applications. Their presence can alter the circuit or the operation of a device, resulting in wrong or even disastrous consequences. To this purpose, in this work, we describe the modeling of SCs in HV capacitive dividers. Such modeling does not rely on finite element analysis or complicated geometries; instead, it starts from an equivalent circuit of a conventional measurement setup described by the standard IEC 61869-11. Once the equivalent model including the SCs is found, closed expressions of the SCs are derived starting from the ratio error definition. Afterwards, they are validated in a simulation environment by implementing various circuit configurations. The results demonstrate the expressions applicability and effectiveness; hence, thanks to their simplicity, they can be implemented by system operators, researchers, and manufacturers avoiding the use of complicated methods and technologies.
Model-Based Design of a Pseudo-Cogenerative Heating System for e-Boat Battery Cold Start
Dario Fusai, Alessandro Soldati, Davide Lusignani, Paolo Santarelli, Paolo Patroncini
April 13, 2023 (v1)
Subject: Environment
Keywords: Batteries, energy management, environmental factors, Modelling, power conversion, thermal management
Full-electric boats are an expression of recent advancements in the area of vessel electrification. The installed batteries can suffer from poor cold-start performance, especially in the frigid season and at higher latitudes, leading to driving power limitations immediately after startup. At state, the leading solution is to adopt a dedicated heater placed on the common cooling/heating circuit; this implies poor volume, weight, and cost figures, given the very limited duty cycle of such a part. The Heater-in-Converter (HiC) technology allows removing this specialized component, exploiting the power electronics converters already available on board: HiC modulates their efficiency to produce valuable heat (pseudo-cogeneration). In this work, we use the model-based approach to design this system, which requires heating power minimization to fulfill power electronics limitations, while guaranteeing the user-expected startup time to full power. A multistage model is used to get the yearly v... [more]
Modeling Water Droplet Freezing and Collision with a Solid Surface
Doston Shayunusov, Dmitry Eskin, Boris V. Balakin, Svyatoslav Chugunov, Stein Tore Johansen, Iskander Akhatov
April 13, 2023 (v1)
Keywords: breakage, collision, crystallization, droplet–wall sticking probability, ice crust, ice-accretion, Modelling
Water droplets released from the sea surface represent one of the major causes of ice accretion on marine vessels. A one-dimensional model of the freezing of a spherical water droplet moving in cold air was developed. The crystallization model allows one to obtain an analytical solution if a uniform temperature distribution over the liquid’s core is assumed. The model was validated using STAR CCM+ Computational fluid dynamics (CFD) code. A collision of a partially frozen droplet with a solid wall assuming the plastic deformation of an ice crust was also considered. The ratio of the crust deformation to the crust thickness was evaluated. It was assumed that if this ratio were to exceed unity, the droplet would stick to the wall’s surface due to ice bridge formation caused by the water released from the droplet’s core.
A Systematic Review on Predicting and Forecasting the Electrical Energy Consumption in the Manufacturing Industry
Jessica Walther, Matthias Weigold
April 13, 2023 (v1)
Keywords: Energy, forecasting, manufacturing, Modelling, prediction
In the context of the European Green Deal, the manufacturing industry faces environmental challenges due to its high demand for electrical energy. Thus, measures for improving the energy efficiency or flexibility are applied to address this problem in the manufacturing industry. In order to quantify energy efficiency or flexibility potentials, it is often necessary to predict or forecast the energy consumption. This paper presents a systematic review of state-of-the-art of existing approaches to predict or forecast the energy consumption in the manufacturing industry. Seventy-two articles are classified according to the defined categories System Boundary, Modelling Technique, Modelling Focus, Modelling Horizon, Modelling Perspective, Modelling Purpose and Model Output. Based on the reviewed articles future research activities are derived.
Improved Modeling of a Multi-Level Inverter for TACS to Reduce Computational Time and Improve Accuracy
Sung-An Kim
April 13, 2023 (v1)
Subject: Other
Keywords: induction motor, Modelling, multi-level inverter, pulse width modulation, variable speed drive
A modeling of a turbo air compressor system (TACS), with a multi-level inverter for driving variable speed, combining an electrical model of an electric motor drive system (EMDS) and a mechanical model of a turbo air compressor, is essential to accurately analyze dynamics characteristics. Compared to the mechanical model, the electrical model has a short sampling time due to the high frequency switching operation of the numerous power semiconductors inside the multi-level inverter. This causes the problem of increased computational time for dynamic characteristics analysis of TACS. To solve this problem, the conventional model of the multi-level inverter has been proposed to simplify the switching operation of the power semiconductors, however it has low accuracy because it does not consider pulse width modulation (PWM) operation. Therefore, this paper proposes an improved modeling of the multi-level inverter for TACS to reduce computational time and improve the accuracy of electrical... [more]
Modelling of a Flow-Induced Oscillation, Two-Cylinder, Hydrokinetic Energy Converter Based on Experimental Data
Yanfang Lv, Liping Sun, Michael M. Bernitsas, Mengjie Jiang, Hai Sun
April 13, 2023 (v1)
Keywords: backpropagation neural network, flow-induced oscillation, galloping, harnessed power and efficiency, Modelling, two tandem cylinders, vortex-induced oscillation
The VIVACE Converter consists of cylindrical oscillators in tandem subjected to transverse flow-induced oscillations (FIOs) that can be improved by varying the system parameters for a given in-flow velocity: damping, stiffness, and in-flow center-to-center spacing. Compared to a single isolated cylinder, tandem cylinders can harness more hydrokinetic energy due to synergy in FIO. Experimental and numerical methods have been utilized to analyze the FIO and energy harnessing of VIVACE. A surrogate-based model of two tandem cylinders is developed to predict the power harvesting and corresponding efficiency by introducing a backpropagation neural network. It is then utilized to reduce excessive experimental or computational testing. The effects of spacing, damping, and stiffness on harvested power and efficiency of the established prediction-model are analyzed. At each selected flow velocity, optimization results of power harvesting using the prediction-model are calculated under different... [more]
Some Aspects of the Modelling of Thin-Layer Drying of Sawdust
Andrzej Bryś, Agnieszka Kaleta, Krzysztof Górnicki, Szymon Głowacki, Weronika Tulej, Joanna Bryś, Piotr Wichowski
April 13, 2023 (v1)
Keywords: dehydration, drying, mechanical engineering, Modelling, sawdust
Drying of spruce, beech, willow, and alder sawdust was examined in a laboratory type dryer. The effect of drying air temperature T (25, 60, and 80 °C) and airflow velocity v (0.01, 0.15, and 1.5 m/s) was investigated. The obtained results demonstrated that drying air temperature and airflow velocity have impacts on the drying of sawdust. The experimental dehydration data of sawdust obtained were fitted to theoretical, semi-theoretical, and empirical thin-layer models. The accuracies of the models were estimated using the correlation coefficient (R), root mean square error (RMSE), and reduced chi-square (χ2). All models except the theoretical model of a sphere described the drying characteristics of sawdust satisfactorily. The effect of T and v on the parameters (constants and coefficients) of the drying models were determined. The effect, by the proposed equations, was also described. This work combines aspects of mechanical engineering and modelling of the drying process.
Design Parameters of a Double-Slope Solar Still: Modelling, Sensitivity Analysis, and Optimization
Hossein Yousefi, Mohamad Aramesh, Bahman Shabani
April 13, 2023 (v1)
Keywords: desalination, design optimization, double slope solar still, Modelling, sensitivity analysis, solar thermal energy
This study presents a novel, highly detailed, and accurate modelling method for calculation of the total annual solar thermal energy received by a double-slope solar still. The model is further utilized for sensitivity analysis and optimization with the help of Genetic Algorithm and TOPSIS methods. The model reveals that the main parameters that can independently affect solar energy input are the basin length, width, tilt angle, surface azimuth angle, and the glass covers’ inclination angle. The sensitivity of the annual solar energy input to all these parameters is analyzed. Moreover, all the parameters are chosen to be involved in the optimization problem. Sensitivity analysis results show that except for basin azimuth angle all other parameters significantly affect the amount of energy input to the solar still. Genetic Algorithm identified 60 optimum sets of parameters, one of which was selected by the TOPSIS method. The optimum values for the basin width, length, tilt and azimuth a... [more]
Interactive Scenario-Based Assessment Approach of Urban Street Lighting and Its Application to Estimating Energy Saving Benefits
Boris A. Portnov, Rami Saad, Tamar Trop
April 13, 2023 (v1)
Subject: Environment
Keywords: Modelling, perceived lighting quality index (PLQI), scenario-assessment, street lighting (SL), urban environment
If excessive and misdirected, street lighting (SL) causes energy waste and might pose significant risks to humans and natural ecosystems. Based on data collected by an interactive user-oriented method, we developed a novel empirical approach that enables the spatial identification of over-illuminated areas in residential neighborhoods and calculation of potential energy savings that can be achieved there, by reducing excessive illumination. We applied the estimated model to a densely populated residential neighborhood in the City of Tel Aviv-Yafo in Israel, to test the proposed approach’s performance. According to our estimates, illumination levels can be lowered by up to 50% in approximately 60% of the neighborhood’s area, which is currently over-illuminated, thus leading to significant energy savings, while preserving a reasonable level of visual comfort associated with SL.
Impact of Dropwise Condensation on the Biomass Production Rate in Covered Raceway Ponds
Jack Hoeniges, Keyong Zhu, Jeremy Pruvost, Jack Legrand, El-khider Si-Ahmed, Laurent Pilon
April 12, 2023 (v1)
Keywords: biofuel, bioprocess engineering, design, light transfer, Modelling, photobioreactor
This study investigates the effect of condensed water droplets on the areal biomass productivity of outdoor culture systems with a free surface, protected by a transparent window or cover to prevent contamination and to control the growth conditions. Under solar radiation, evaporation from the culture causes droplets to condense on the interior surface of the cover. To quantify the effect of droplets on the system’s performance, the bidirectional transmittance of a droplet-covered window was predicted using the Monte Carlo ray-tracing method. It was combined with a growth kinetics model of Chlorella vulgaris to predict the temporal evolution of the biomass concentration on 21 June and 23 September in Los Angeles, CA. A droplet contact angle of 30∘ or 90∘ and a surface area coverage of 50% or 90% were considered. Light scattering by the condensed droplets changed the direction of the incident sunlight while reducing the amount of light reaching the culture by up to 37%. The combined eff... [more]
Numerical Modeling and Optimization of an Air Handling Unit
José Lopes, João Silva, Senhorinha Teixeira, José Teixeira
April 12, 2023 (v1)
Keywords: air handling unit, Computational Fluid Dynamics, flow control unit, Modelling
Concerns about the efficiency of Heating, Ventilating, and Air Conditioning systems, including Air Handling Units (AHUs), started in the last century due to the energy crisis. Thenceforth, important improvements on the AHUs performance have emerged. Among the various improvements, the control of the AHUs and the redesign of the fans are the most important ones. Although, with increasingly demanding energy efficiency requirements, other constructive solutions must be investigated. Therefore, the objective of this work is to investigate, using a computational fluid dynamics (CFD) tool, the fluid flow inside an AHU and to analyze different constructive solutions in order to improve the AHU performance. The numerical model provided a reasonable agreement with the experimental results in terms of air flow rate, despite the assumed simplifications. Regarding the constructive solution concept, the CFD results for the two different flow control units (FCUs) showed improvements in terms of fan... [more]
Modelling Future Agricultural Mechanisation of Major Crops in China: An Assessment of Energy Demand, Land Use and Emissions
Iván García Kerdan, Sara Giarola, Ellis Skinner, Marin Tuleu, Adam Hawkes
April 12, 2023 (v1)
Keywords: agriculture, China, Energy, land use, mechanisation, Modelling
Agricultural direct energy use is responsible for about 1−2% of global emissions and is the major emitting sector for methane (2.9 GtCO2eq y−1) and nitrous oxide (2.3 GtCO2eq y−1). In the last century, farm mechanisation has brought higher productivity levels and lower land demands at the expense of an increase in fossil energy and agrochemicals use. The expected increase in certain food and bioenergy crops and the uncertain mitigation options available for non-CO2 emissions make of vital importance the assessment of the use of energy and the related emissions attributable to this sector. The aim of this paper is to present a simulation framework able to forecast energy demand, technological diffusion, required investment and land use change of specific agricultural crops. MUSE-Ag & LU, a novel energy systems-oriented agricultural and land use model, has been used for this purpose. As case study, four main crops (maize, soybean, wheat and rice) have been modelled in mainland China. Bes... [more]
The Use of Hypergeometric Functions in Hysteresis Modeling
Dejana Herceg, Krzysztof Chwastek, Đorđe Herceg
April 11, 2023 (v1)
Subject: Materials
Keywords: ferromagnetic materials, hysteresis loop, Modelling
Accurate hysteresis models are necessary for modeling of magnetic components of devices such as transformers and motors. This study presents a hysteresis model with a convenient analytical form, based on hypergeometric functions with one free parameter, built upon a class of parameterized curves. The aim of this work is to explore suitability of the presented model for describing major and minor loops, as well as to demonstrate improved agreement between experimental and modeled hysteresis loops. The procedure for generating first order reversal curves is also discussed. The added parameter, introduced into the model, controls the shape of the model curve, especially near saturation. It can be adjusted to provide better agreement between measured and model curves. The model parameters are nonlinearly dependent; therefore, they are determined in a nonlinear curve fitting procedure. The choice of the initial approximation and a suitable set of constraints for the optimization procedure a... [more]
Drying Kinetics, Physicochemical and Thermal Analysis of Onion Puree Dried Using a Refractance Window Dryer
Ruchika Zalpouri, Manpreet Singh, Preetinder Kaur, Amrit Kaur, Kirtiraj K. Gaikwad, Ashutosh Singh
April 11, 2023 (v1)
Keywords: artificial neural network, convective drying, Modelling, onion puree, quality, refractance window drying
Onions have a high moisture content, which makes them more susceptible to microbial growth. Drying is one of the postharvest preservation methods applied to decrease onion moisture content, thereby increasing its storage life. In this study, onions were peeled, washed, cut into quarters, hot water blanched, and pureed. The puree was further dried using two different drying methods: refractance window drying (RWD) (water temperature: 70 °C) and convective drying (CD) (50 °C). The puree was spread on prefabricated trays at varying thicknesses of 2 mm, 4 mm, and 6 mm. It was observed that, irrespective of the drying method, moisture ratio (MR) decreased and drying time and effective moisture diffusivity increased with respect to the thickness of the puree. In addition, the Lewis model and the Wang and Singh model showed the highest R2 and lowest SEE value for RWD and CD, respectively. Moreover, the MR of onion puree during RWD and CD was predicted using a multi-layer feed-forward (MLF) ar... [more]
A Tool Condition Monitoring System Based on Low-Cost Sensors and an IoT Platform for Rapid Deployment
Johanna Marie Failing, José V. Abellán-Nebot, Sergio Benavent Nácher, Pedro Rosado Castellano, Fernando Romero Subirón
April 11, 2023 (v1)
Keywords: industrial internet of things, IoT platform, logistic regression, Modelling, tool condition monitoring
Tool condition monitoring (TCM) systems are key technologies for ensuring machining efficiency. Despite the large number of TCM solutions, these systems have not been implemented in industry, especially in small- and medium-sized enterprises (SMEs), mainly because of the need for invasive sensors, time-consuming deployment solutions and a lack of straightforward, scalable solutions from the laboratory. The implementation of TCM solutions for the new era of the Industry 4.0 is encouraging practitioners to look for systems based on IoT (Internet of Things) platforms with plug and play capabilities, minimum interruption time during setup and minimal experimental tests. In this paper, we propose a TCM system based on low-cost and non-invasive sensors that are plug and play devices, an IoT platform for fast deployment and a mobile app for receiving operator feedback. The system is based on a sensing node by Arduino Uno Wi-Fi that acts as an edge-computing node to extract a similarity index... [more]
A Review of the Thermochemical Behaviour of Fluxes in Submerged Arc Welding: Modelling of Gas Phase Reactions
Theresa Coetsee, Frederik De Bruin
April 11, 2023 (v1)
Keywords: aluminium, basicity, flux, gas, Modelling, oxygen, SAW, slag, thermodynamics, weld metal, welding
This review is focused on the thermochemical behaviour of fluxes in submerged arc welding (SAW). The English-language literature from the 1970s onwards is reviewed. It was recognised early on that the thermochemical behaviour of fluxes sets the weld metal total ppm O and the element transfer extent from the molten flux (slag) to the weld pool. Despite the establishment of this link between the flux-induced oxygen potential and element transfer, it is also well accepted that the slag−metal equilibrium does not control SAW process metallurgy. Instead, the gas phase must be taken into account to better describe SAW process metallurgy equilibrium calculations. This is illustrated in the gas−slag−metal equilibrium simulation model developed by Coetsee. This model provides improved accuracy in predicting the weld metal total ppm O values as compared to the empirical trend of Tuliani et al. Recent works on the application of Al metal powder with alloying metal powders provide new insights int... [more]
High-Impedance Fault Diagnosis: A Review
Abdulaziz Aljohani, Ibrahim Habiballah
April 11, 2023 (v1)
Keywords: artificial neural networks, fault detection techniques, fault location techniques, high-impedance fault, Machine Learning, Modelling, signal processing, Stockwell transform, wavelet transform
High-impedance faults (HIFs) represent one of the biggest challenges in power distribution networks. An HIF occurs when an electrical conductor unintentionally comes into contact with a highly resistive medium, resulting in a fault current lower than 75 amperes in medium-voltage circuits. Under such condition, the fault current is relatively close in value to the normal drawn ampere from the load, resulting in a condition of blindness towards HIFs by conventional overcurrent relays. This paper intends to review the literature related to the HIF phenomenon including models and characteristics. In this work, detection, classification, and location methodologies are reviewed. In addition, diagnosis techniques are categorized, evaluated, and compared with one another. Finally, disadvantages of current approaches and a look ahead to the future of fault diagnosis are discussed.
Efficient Integration of Machine Learning into District Heating Predictive Models
Libor Kudela, Radomír Chýlek, Jiří Pospíšil
April 11, 2023 (v1)
Keywords: district heating, dynamics, Machine Learning, Modelling, Optimization, pipes, smart systems
Modern control strategies for district-level heating and cooling supply systems pose a difficult challenge. In order to integrate a wide range of hot and cold sources, these new systems will rely heavily on accumulation and much lower operating temperatures. This means that predictive models advising the control strategy must take into account long-lasting thermal effects but must not be computationally too expensive, because the control would not be possible in practice. This paper presents a simple but powerful systematic approach to reducing the complexity of individual components of such models. It makes it possible to combine human engineering intuition with machine learning and arrive at comprehensive and accurate models. As an example, a simple steady-state heat loss of buried pipes is extended with dynamics observed in a much more complex model. The results show that the process converges quickly toward reasonable solutions. The new auto-generated model performs 5 × 104 times f... [more]
Numerical and Experimental Analysis of Heat Transfer for Solid Fuels Combustion in Fixed Bed Conditions
Wojciech Judt
April 4, 2023 (v1)
Keywords: combustion, Computational Fluid Dynamics, experimental analysis, fixed bed, heat load, heat transfer, Modelling, solid fuels
The paper concerns the analysis of the heat transfer process that occurred during solid fuel burning in fixed bed conditions. The subject of the analysis is a cylindrical combustion chamber with an output of 12 kW heating power equipped with a retort burner for hard coal and biomass combustion. During the research, a numerical and experimental study is performed. The analysis is prepared for various heat load of the combustion chamber, which allowed for the reconstruction of real working conditions for heating devices working with solid fuels combustion. The temperature distribution obtained by the experimental way is compared with results of the numerical modeling. Local distribution of principal heat transfer magnitudes like a heat flux density and a heat transfer coefficient that occurred on the sidewall of the combustion chamber is analyzed. The analysis showed, that the participation of convection and radiation in the overall heat transfer process has resulted from the heat load o... [more]
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