In this paper, a novel system based on the combination of a supercritical recompression Brayton cycle (SRBC) and LiBr-H2O absorption refrigeration cycle (ARC) is proposed, in which ARC utilizes the waste heat of SRBC for cooling and further reduces main compressor inlet temperature. The potential of using xenon and krypton as additives for supercritical CO2 Brayton cycle is explored via comparative analysis. The results show that CO2/Krypton is more suitable to be working fluid of combined system because of its higher thermal efficiency and lower costs. The effects of the operating parameters and mass fraction of krypton on the thermo-economic performance of combined system are discussed. Multi-objective optimization is applied to simultaneously optimize the thermal efficiency and total product unit cost of the system. Compared with stand-alone cycle, combined system can improve the cycle efficiency over a wide temperature range. The exergy efficiency of SRBC/ARC using CO2/Krypton (0.64/0.36) increased from 0.638 to 0.688, from 0.653 to 0.665, and from 0.586 to 0.646 at ambient temperature T0 = 10, 25, 35°C, respectively, increasing by 7.84%, 1.84% and 10.24% compared with SCO2RBC. The combined system will achieve its full potential when the critical temperature of the working fluid is close to the ambient temperature.
{"title":"Thermo-economic comparative study and Multi-objective optimization of supercritical CO2-based mixtures Brayton cycle combined with absorption refrigeration cycle","authors":"Yanan Ma, P. Hu","doi":"10.1115/1.4062435","DOIUrl":"https://doi.org/10.1115/1.4062435","url":null,"abstract":"\u0000 In this paper, a novel system based on the combination of a supercritical recompression Brayton cycle (SRBC) and LiBr-H2O absorption refrigeration cycle (ARC) is proposed, in which ARC utilizes the waste heat of SRBC for cooling and further reduces main compressor inlet temperature. The potential of using xenon and krypton as additives for supercritical CO2 Brayton cycle is explored via comparative analysis. The results show that CO2/Krypton is more suitable to be working fluid of combined system because of its higher thermal efficiency and lower costs. The effects of the operating parameters and mass fraction of krypton on the thermo-economic performance of combined system are discussed. Multi-objective optimization is applied to simultaneously optimize the thermal efficiency and total product unit cost of the system. Compared with stand-alone cycle, combined system can improve the cycle efficiency over a wide temperature range. The exergy efficiency of SRBC/ARC using CO2/Krypton (0.64/0.36) increased from 0.638 to 0.688, from 0.653 to 0.665, and from 0.586 to 0.646 at ambient temperature T0 = 10, 25, 35°C, respectively, increasing by 7.84%, 1.84% and 10.24% compared with SCO2RBC. The combined system will achieve its full potential when the critical temperature of the working fluid is close to the ambient temperature.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"113 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89547432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract As rotating detonation engines (RDEs) progress in maturity, the importance of monitoring advancements toward development of active control becomes more critical. Experimental RDE data processing at time scales which satisfy real-time diagnostics will likely require the use of machine learning. This study aims to develop and deploy a novel real-time monitoring technique capable of determining detonation wave number, direction, frequency, and individual wave speeds throughout experimental RDE operational windows. To do so, the diagnostic integrates image classification by a convolutional neural network (CNN) and ionization current signal analysis. Wave mode identification through single-image CNN classification bypasses the need to evaluate sequential images and offers instantaneous identification of the wave mode present in the RDE annulus. Real-time processing speeds are achieved due to low data volumes required by the methodology, namely one short-exposure image and a short window of sensor data to generate each diagnostic output. The diagnostic acquires live data using a modified experimental setup alongside Pylon and PyDAQmx libraries within a python data acquisition environment. Lab-deployed diagnostic results are presented across varying wave modes, operating conditions, and data quality, currently executed at 3–4 Hz with a variety of iteration speed optimization options to be considered as future work. These speeds exceed that of conventional techniques and offer a proven structure for real-time RDE monitoring. The demonstrated ability to analyze detonation wave presence and behavior during RDE operation will certainly play a vital role in the development of RDE active control, necessary for RDE technology maturation toward industrial integration.
{"title":"USE OF CONVOLUTIONAL NEURAL NETWORK IMAGE CLASSIFICATION AND HIGH-SPEED ION PROBE DATA TOWARDS REAL-TIME DETONATION CHARACTERIZATION IN A WATER-COOLED ROTATING DETONATION ENGINE","authors":"Kristyn Johnson, Donald Ferguson, Andrew C. Nix","doi":"10.1115/1.4062182","DOIUrl":"https://doi.org/10.1115/1.4062182","url":null,"abstract":"Abstract As rotating detonation engines (RDEs) progress in maturity, the importance of monitoring advancements toward development of active control becomes more critical. Experimental RDE data processing at time scales which satisfy real-time diagnostics will likely require the use of machine learning. This study aims to develop and deploy a novel real-time monitoring technique capable of determining detonation wave number, direction, frequency, and individual wave speeds throughout experimental RDE operational windows. To do so, the diagnostic integrates image classification by a convolutional neural network (CNN) and ionization current signal analysis. Wave mode identification through single-image CNN classification bypasses the need to evaluate sequential images and offers instantaneous identification of the wave mode present in the RDE annulus. Real-time processing speeds are achieved due to low data volumes required by the methodology, namely one short-exposure image and a short window of sensor data to generate each diagnostic output. The diagnostic acquires live data using a modified experimental setup alongside Pylon and PyDAQmx libraries within a python data acquisition environment. Lab-deployed diagnostic results are presented across varying wave modes, operating conditions, and data quality, currently executed at 3–4 Hz with a variety of iteration speed optimization options to be considered as future work. These speeds exceed that of conventional techniques and offer a proven structure for real-time RDE monitoring. The demonstrated ability to analyze detonation wave presence and behavior during RDE operation will certainly play a vital role in the development of RDE active control, necessary for RDE technology maturation toward industrial integration.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135223086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Radio frequency (RF) electronics are developing towards high power, high integration, and high-power density, resulting in a continuous increase in heat flux. The traditional high-power RF package, which is usually composed of aluminum nitride (AlN) substrate, aluminum silicon housing shell, and aluminum alloy cold plate, exhibits poor heat dissipation ability and high thickness due to excessive interfaces and a long thermal conduction path. In this paper, aimed at improving heat dissipation ability and reducing the thickness of RF electronics, the microchannel was transferred from the cold plate to the AlN HTCC substrate which plays the role of electrical connection, structural support, and liquid cooling cold plate. The embedded AlN microchannel cooler was firstly designed. Then, a prototype of the AlN substrate with 64 simulated chip arrays and microchannels was fabricated and the thermal performance was evaluated using an experimental setup. Finally, the thermal performances of the proposed and traditional cooler were compared using a CFD simulation. The results indicated that the proposed embedded cooling structure could enhance the heat flux dissipation ability by 61% and reduce the packaging thickness by 40% compared with the traditional cooling structure.
{"title":"Embedded Microfluidic Cooling in Aluminum Nitride (AlN) HTCC Substrate for High-power RF Chip Array","authors":"Yupu Ma, T. Wei, Jiyu Qian, Jian Peng","doi":"10.1115/1.4062400","DOIUrl":"https://doi.org/10.1115/1.4062400","url":null,"abstract":"\u0000 Radio frequency (RF) electronics are developing towards high power, high integration, and high-power density, resulting in a continuous increase in heat flux. The traditional high-power RF package, which is usually composed of aluminum nitride (AlN) substrate, aluminum silicon housing shell, and aluminum alloy cold plate, exhibits poor heat dissipation ability and high thickness due to excessive interfaces and a long thermal conduction path. In this paper, aimed at improving heat dissipation ability and reducing the thickness of RF electronics, the microchannel was transferred from the cold plate to the AlN HTCC substrate which plays the role of electrical connection, structural support, and liquid cooling cold plate. The embedded AlN microchannel cooler was firstly designed. Then, a prototype of the AlN substrate with 64 simulated chip arrays and microchannels was fabricated and the thermal performance was evaluated using an experimental setup. Finally, the thermal performances of the proposed and traditional cooler were compared using a CFD simulation. The results indicated that the proposed embedded cooling structure could enhance the heat flux dissipation ability by 61% and reduce the packaging thickness by 40% compared with the traditional cooling structure.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"6 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86478495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The aim of this work is to unveil the exergy transfer and overall thermal performance of the metal foams partially filled in varying thicknesses in the vertical channel. The numerical examination performed in this study consists of a heater cum plate assembly which is placed at the core of the vertical channel and the heat transfer from the plates is augmented by placing high thermal conductivity metal foams on either side of the channel. The novelty of the present investigation is to find the optimum filling rate in various thicknesses of the channel with respect to overall thermal performance along with exergy transfer. Four different partial filling rates are considered in each thickness of the channel to find the optimum exergy transfer. The integrated Darcy Extended Forchheimer (DEF) and local thermal non-equilibrium (LTNE) models are used for forecasting the flow features and heat transfer through the metal foam porous medium. The numerical methodology implemented in this research is confirmed by comparing the results with the literature and found a fairly good agreement between them. The flow physiognomies in terms of pressure drop and friction factor, heat transfer performance in terms of Nusselt number and performance factor, exergy transfer in terms of mean exergy based Nusselt number are presented and discussed. Results showed that higher working limits permitted by exergy (WLPERe) is obtained for lesser metal foam filling rate as well as for higher metal foam thicknesses for all the cases examined in the study.
{"title":"Exergy Transfer and Irreversibility of Metal Foams Filled in a Vertical Channel","authors":"K. K, Banjara Kotresha, Kishan Naik","doi":"10.1115/1.4062399","DOIUrl":"https://doi.org/10.1115/1.4062399","url":null,"abstract":"\u0000 The aim of this work is to unveil the exergy transfer and overall thermal performance of the metal foams partially filled in varying thicknesses in the vertical channel. The numerical examination performed in this study consists of a heater cum plate assembly which is placed at the core of the vertical channel and the heat transfer from the plates is augmented by placing high thermal conductivity metal foams on either side of the channel. The novelty of the present investigation is to find the optimum filling rate in various thicknesses of the channel with respect to overall thermal performance along with exergy transfer. Four different partial filling rates are considered in each thickness of the channel to find the optimum exergy transfer. The integrated Darcy Extended Forchheimer (DEF) and local thermal non-equilibrium (LTNE) models are used for forecasting the flow features and heat transfer through the metal foam porous medium. The numerical methodology implemented in this research is confirmed by comparing the results with the literature and found a fairly good agreement between them. The flow physiognomies in terms of pressure drop and friction factor, heat transfer performance in terms of Nusselt number and performance factor, exergy transfer in terms of mean exergy based Nusselt number are presented and discussed. Results showed that higher working limits permitted by exergy (WLPERe) is obtained for lesser metal foam filling rate as well as for higher metal foam thicknesses for all the cases examined in the study.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"61 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83973327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thermal management is a challenging engineering problem for CubeSats due to the limited available volumes restricting the thermal control applications. Therefore, performing thermal modelling and analyses of these small satellites is very crucial for applying proper thermal control measures to maintain safe operating conditions in space. Despite the growing interest in this field, there are still a limited number of studies investigating thermal behavior of CubeSats. In this paper, surface temperature profiles of 1U, 2U, 3U, 5U, 6U and 12U sized CubeSats are simulated for varying low earth orbits. The effects of altitudes changing between 400 km to 2000 km and the beta angles changing between 0 to 75 degrees are analytically investigated. Not only the coatings with different absorptance and emissivity values but also different amounts of internal heat dissipations are examined to reveal their impact on thermal balance of satellites. Results demonstrate surface temperatures are highly depended on those variables. The amount of heat absorbed by satellite panels are affected by different sizes of CubeSats, different coating properties of panels and different orbital configurations. The outcomes of this research may be beneficial especially in the early design phase for designing of small satellites and selecting proper orbital configurations.
{"title":"Analytical investigation of surface temperatures for different sized CubeSats at varying Low Earth Orbits","authors":"C. Atar, M. Aktaş, N. Sözbir, M. Bulut","doi":"10.1115/1.4062401","DOIUrl":"https://doi.org/10.1115/1.4062401","url":null,"abstract":"\u0000 Thermal management is a challenging engineering problem for CubeSats due to the limited available volumes restricting the thermal control applications. Therefore, performing thermal modelling and analyses of these small satellites is very crucial for applying proper thermal control measures to maintain safe operating conditions in space. Despite the growing interest in this field, there are still a limited number of studies investigating thermal behavior of CubeSats. In this paper, surface temperature profiles of 1U, 2U, 3U, 5U, 6U and 12U sized CubeSats are simulated for varying low earth orbits. The effects of altitudes changing between 400 km to 2000 km and the beta angles changing between 0 to 75 degrees are analytically investigated. Not only the coatings with different absorptance and emissivity values but also different amounts of internal heat dissipations are examined to reveal their impact on thermal balance of satellites. Results demonstrate surface temperatures are highly depended on those variables. The amount of heat absorbed by satellite panels are affected by different sizes of CubeSats, different coating properties of panels and different orbital configurations. The outcomes of this research may be beneficial especially in the early design phase for designing of small satellites and selecting proper orbital configurations.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"18 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80077927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Compressibility and rarefaction effect plays an essential role in the design and study of objects experiencing hypersonic flows. The presence of chemical and thermal non-equilibrium in hypersonic flows increases the complexity of estimating aerothermodynamic properties, which are essential for developing thermal protection systems and the aerothermodynamic design of hypersonic vehicles. In this study, the hy2Foam solver, is used to understand the effect of Knudsen number (which in turn depends on the altitude) and free-stream enthalpy variation on the surface aerothermodynamic properties such as pressure, heat flux, velocity slip, temperature jump, and flow-field variables such as species concentration and temperature, in five-species air flow over a cylinder, for both noncatalytic and fully catalytic wall condition. The novelty of the work lies in reporting the effect of rarefaction on thermal and chemical non-equilibrium (associated with hypersonic flows), and thus on the surface properties under different enthalpy and wall catalytic condition. It has been shown the rarefaction effect is more pronounced on the vibrational temperature component, and for high enthalpy gas. The surface wall heat flux and the chemical reaction rate among the species decrease with rarefaction. The skin friction coefficient is one of the most sensitive properties, while the pressure coefficient has been the least susceptible to non-equilibrium effects. The stagnation points heat flux at different Knudsen numbers shows good agreement with the existing correlation in literature for low and high enthalpy flows, which further establishes the validity of the study done in this work.
{"title":"Effect of rarefaction on thermal and chemical non-equilibrium for Hypersonic flow with different enthalpy and catalytic wall conditions","authors":"Shubham Kumar, A. Assam","doi":"10.1115/1.4062358","DOIUrl":"https://doi.org/10.1115/1.4062358","url":null,"abstract":"\u0000 Compressibility and rarefaction effect plays an essential role in the design and study of objects experiencing hypersonic flows. The presence of chemical and thermal non-equilibrium in hypersonic flows increases the complexity of estimating aerothermodynamic properties, which are essential for developing thermal protection systems and the aerothermodynamic design of hypersonic vehicles. In this study, the hy2Foam solver, is used to understand the effect of Knudsen number (which in turn depends on the altitude) and free-stream enthalpy variation on the surface aerothermodynamic properties such as pressure, heat flux, velocity slip, temperature jump, and flow-field variables such as species concentration and temperature, in five-species air flow over a cylinder, for both noncatalytic and fully catalytic wall condition. The novelty of the work lies in reporting the effect of rarefaction on thermal and chemical non-equilibrium (associated with hypersonic flows), and thus on the surface properties under different enthalpy and wall catalytic condition. It has been shown the rarefaction effect is more pronounced on the vibrational temperature component, and for high enthalpy gas. The surface wall heat flux and the chemical reaction rate among the species decrease with rarefaction. The skin friction coefficient is one of the most sensitive properties, while the pressure coefficient has been the least susceptible to non-equilibrium effects. The stagnation points heat flux at different Knudsen numbers shows good agreement with the existing correlation in literature for low and high enthalpy flows, which further establishes the validity of the study done in this work.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"17 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86089196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
As the main energy consumption part of the central air-conditioning system, the energy saving of the chilled water system is particularly important. In this paper, an improved fruit fly optimization algorithm (IFOA) is used to optimize the operation parameters of the chilled water system to reduce the energy consumption of the chilled water system. In IFOA, the three-dimensional position coordinate is introduced to expand the search space of the algorithm, and the variable step strategy balances the global search ability and local search ability of the algorithm, and helps a single Drosophila jump out of the local optimization through chaos mapping. In order to verify the optimization effect of IFOA on the chilled water system, the energy consumption model of the chilled water system is established. With the lowest total energy consumption of the system as the goal, the operating parameters such as the chilled water supply temperature and the speed ratio of the chilled water pump are optimized. The simulation results show that the energy saving optimization method of central air-conditioning chilled water system based on IFOA can make the average energy saving rate of the system reach 7.9%. Compared with other optimization algorithms, the method has better energy saving effect and is more stable.
{"title":"Energy saving optimization of chilled water system based on improved fruit fly optimization algorithm","authors":"Zengxi Feng, Wenjing Wang, Xin He, Gang Li, Lutong Zhang, Weipeng Xiang","doi":"10.1115/1.4062359","DOIUrl":"https://doi.org/10.1115/1.4062359","url":null,"abstract":"\u0000 As the main energy consumption part of the central air-conditioning system, the energy saving of the chilled water system is particularly important. In this paper, an improved fruit fly optimization algorithm (IFOA) is used to optimize the operation parameters of the chilled water system to reduce the energy consumption of the chilled water system. In IFOA, the three-dimensional position coordinate is introduced to expand the search space of the algorithm, and the variable step strategy balances the global search ability and local search ability of the algorithm, and helps a single Drosophila jump out of the local optimization through chaos mapping. In order to verify the optimization effect of IFOA on the chilled water system, the energy consumption model of the chilled water system is established. With the lowest total energy consumption of the system as the goal, the operating parameters such as the chilled water supply temperature and the speed ratio of the chilled water pump are optimized. The simulation results show that the energy saving optimization method of central air-conditioning chilled water system based on IFOA can make the average energy saving rate of the system reach 7.9%. Compared with other optimization algorithms, the method has better energy saving effect and is more stable.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"26 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85121934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The development of prediction models for solar thermal systems has been a research interest for many years. The present study focuses on developing prediction model for solar box cookers (SBCs) through computational, and machine learning (ML) approaches. We aim to forecast cooking load temperatures of SBC through ML techniques such as random forest (RF), k-Nearest Neighbor (k-NN), linear regression, and decision tree. ML is a commonly used form of artificial intelligence, and it continues to be popular and attractive as it finds new applications every day. A numerical model based on thermal balance is used to generate the data set for the ML algorithm considering different locations across the world. Experiments on the SBC in Indian weather conditions are conducted from January through March 2022 to validate the numerical model. The temperatures for different components obtained through numerical modeling agree with experimental values with less than 7% maximum error. Although all the developed models can predict the temperature of cooking load, the RF model outperformed the other models. The root mean square error (RMSE), determination coefficient (R2), mean absolute error (MAE), and mean square error (MSE) for the RF model are 2.14 (°C), 0.992, 1.45 (°C) and 4.58 (°C), respectively. The regression coefficients indicate that the RF model can accurately predict the thermal parameters of SBCs with great precision. This study will inspire researchers to explore the possibilities of ML prediction models for solar thermal conversion applications.
{"title":"Performance prediction model development for solar box cooker using computational and machine learning techniques","authors":"Anilkumar B.C., Ranjith Maniyeri, A. S","doi":"10.1115/1.4062357","DOIUrl":"https://doi.org/10.1115/1.4062357","url":null,"abstract":"\u0000 The development of prediction models for solar thermal systems has been a research interest for many years. The present study focuses on developing prediction model for solar box cookers (SBCs) through computational, and machine learning (ML) approaches. We aim to forecast cooking load temperatures of SBC through ML techniques such as random forest (RF), k-Nearest Neighbor (k-NN), linear regression, and decision tree. ML is a commonly used form of artificial intelligence, and it continues to be popular and attractive as it finds new applications every day. A numerical model based on thermal balance is used to generate the data set for the ML algorithm considering different locations across the world. Experiments on the SBC in Indian weather conditions are conducted from January through March 2022 to validate the numerical model. The temperatures for different components obtained through numerical modeling agree with experimental values with less than 7% maximum error. Although all the developed models can predict the temperature of cooking load, the RF model outperformed the other models. The root mean square error (RMSE), determination coefficient (R2), mean absolute error (MAE), and mean square error (MSE) for the RF model are 2.14 (°C), 0.992, 1.45 (°C) and 4.58 (°C), respectively. The regression coefficients indicate that the RF model can accurately predict the thermal parameters of SBCs with great precision. This study will inspire researchers to explore the possibilities of ML prediction models for solar thermal conversion applications.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"5 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89238022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, the performance of the forced cross-flow water cooling tower was investigated with the ANSYS CFX program. The geometric dimensions and boundary condition values of the cooling towers in the study were taken to be close to the real values. The effect of air velocity, water droplet diameter and inlet water temperature change according to the temperature of the water coming out of the 2m wide, 2m long and 3m high cooling tower was investigated. For the cooling tower, data values suitable for design are selected. The study used air velocities of 2 m/s, 4 m/s, 6 m/s, and 8 m/s, water droplet diameters of 0.01, 0.008, 0.005, and 0.001 m, and inlet water temperatures of 306.15, 309.15, 311.15, and 313.15 K). In addition, the relationship between cooling range and air velocity for mass flow values of different process waters was also investigated. As a result of the study, it was observed that the process leaving water temperatures decreased with the increase of air velocities, but the cooling range increased. A similar situation was observed with the reduction of water droplet diameters. However, it has been observed that when the inlet water temperatures are increased, the outlet process water temperatures and the cooling interval also increase.
{"title":"Numerical Investigation of Cross-Flow Water Cooling Towers","authors":"Ö. Can, Muhammed Alabbas","doi":"10.1115/1.4062356","DOIUrl":"https://doi.org/10.1115/1.4062356","url":null,"abstract":"\u0000 In this study, the performance of the forced cross-flow water cooling tower was investigated with the ANSYS CFX program. The geometric dimensions and boundary condition values of the cooling towers in the study were taken to be close to the real values. The effect of air velocity, water droplet diameter and inlet water temperature change according to the temperature of the water coming out of the 2m wide, 2m long and 3m high cooling tower was investigated. For the cooling tower, data values suitable for design are selected. The study used air velocities of 2 m/s, 4 m/s, 6 m/s, and 8 m/s, water droplet diameters of 0.01, 0.008, 0.005, and 0.001 m, and inlet water temperatures of 306.15, 309.15, 311.15, and 313.15 K). In addition, the relationship between cooling range and air velocity for mass flow values of different process waters was also investigated. As a result of the study, it was observed that the process leaving water temperatures decreased with the increase of air velocities, but the cooling range increased. A similar situation was observed with the reduction of water droplet diameters. However, it has been observed that when the inlet water temperatures are increased, the outlet process water temperatures and the cooling interval also increase.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"22 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90058596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the present work, we propose an efficient thermoelectric cooler design for mitigating the cooling demand of high-end electronic components such as microprocessors, semiconductor lasers, etc. A 3D numerical model is developed using the finite element method (FEM) based commercial software COMSOL Multiphysics to investigate the effect of various geometric and operating parameters on the cooling performance of the thermoelectric cooler. The parameters such as fill factor, leg dimensions, heat sink size, and phase change material (PCM) filling pattern in the inter-fin spacings/gaps are optimized. Two heat sink PCM designs, M1 (alternate fin gaps filled) and M2 (all fin gaps filled), are investigated for hotspot mitigation. For no load conditions, the thermoelectric cooler module with a 20% fill factor produces a cooling of 20.5 °C with an average cooling per unit input power of 37.5°CW−1. When a heating load of 625 W/cm>2 is applied, its cold-side temperature reaches 91 °C. TEC module with n-eicosane PCM (M2 design) provides an effective cooling of 37 °C and an average cooling per unit input power of 42.3°CW−1. spacings/gaps are optimized. OM32 and n-eicosane were the two PCMs employed in the present study. The cold-side temperature reached 91 oC at the heating load of 625 W/cm2 when the thermoelectric cooler (TEC) device is switched OFF. The cold side temperature of the TEC dropped by 37 oC after 500 s at an input current of 7 A.
{"title":"Efficient Thermoelectric Cooler for Localized Cooling in Electronic Devices","authors":"Rishikesh Kumar, Mohd. Kaleem Khan, M. Pathak","doi":"10.1115/1.4062333","DOIUrl":"https://doi.org/10.1115/1.4062333","url":null,"abstract":"\u0000 In the present work, we propose an efficient thermoelectric cooler design for mitigating the cooling demand of high-end electronic components such as microprocessors, semiconductor lasers, etc. A 3D numerical model is developed using the finite element method (FEM) based commercial software COMSOL Multiphysics to investigate the effect of various geometric and operating parameters on the cooling performance of the thermoelectric cooler. The parameters such as fill factor, leg dimensions, heat sink size, and phase change material (PCM) filling pattern in the inter-fin spacings/gaps are optimized. Two heat sink PCM designs, M1 (alternate fin gaps filled) and M2 (all fin gaps filled), are investigated for hotspot mitigation. For no load conditions, the thermoelectric cooler module with a 20% fill factor produces a cooling of 20.5 °C with an average cooling per unit input power of 37.5°CW−1. When a heating load of 625 W/cm>2 is applied, its cold-side temperature reaches 91 °C. TEC module with n-eicosane PCM (M2 design) provides an effective cooling of 37 °C and an average cooling per unit input power of 42.3°CW−1. spacings/gaps are optimized. OM32 and n-eicosane were the two PCMs employed in the present study. The cold-side temperature reached 91 oC at the heating load of 625 W/cm2 when the thermoelectric cooler (TEC) device is switched OFF. The cold side temperature of the TEC dropped by 37 oC after 500 s at an input current of 7 A.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"30 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87147622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：