Pub Date : 2024-10-01DOI: 10.1016/j.tsep.2024.102946
Shen Gao , Xian Wang , Yunxiao Wang , Yanxing Zhao , Maoqiong Gong
Accurate monitoring of subcutaneous temperature is crucial for the safety and efficacy of cryolipolysis. However, existing measurement and simulation methods often require trade-offs between accuracy, depth, and computational efficiency. This study introduces a novel deep learning architecture, ConvD-DeepONet, specifically designed to predict subcutaneous temperature fields with both high accuracy and efficiency. The model effectively captures spatial information and produces multi-dimensional output, owing to the innovative integration of convolutional layers and the decoder network. An average absolute error (MAE) of 0.0038 ℃ and a root mean square error (RMSE) of 0.0083 ℃ are achieved, resulting in over a 50 % reduction compared to the baseline models. Moreover, each prediction is completed in just 5.9 ms, rendering it 120 times faster than traditional finite element method simulations. These results indicate that ConvD-DeepONet is a promising tool for real-time subcutaneous temperature prediction, with the potential to enhance the safety and efficacy of cryolipolysis.
{"title":"Predicting the subcutaneous temperature in cryolipolysis using deep operator networks","authors":"Shen Gao , Xian Wang , Yunxiao Wang , Yanxing Zhao , Maoqiong Gong","doi":"10.1016/j.tsep.2024.102946","DOIUrl":"10.1016/j.tsep.2024.102946","url":null,"abstract":"<div><div>Accurate monitoring of subcutaneous temperature is crucial for the safety and efficacy of cryolipolysis. However, existing measurement and simulation methods often require trade-offs between accuracy, depth, and computational efficiency. This study introduces a novel deep learning architecture, ConvD-DeepONet, specifically designed to predict subcutaneous temperature fields with both high accuracy and efficiency. The model effectively captures spatial information and produces multi-dimensional output, owing to the innovative integration of convolutional layers and the decoder network. An average absolute error (MAE) of 0.0038 ℃ and a root mean square error (RMSE) of 0.0083 ℃ are achieved, resulting in over a 50 % reduction compared to the baseline models. Moreover, each prediction is completed in just 5.9 ms, rendering it 120 times faster than traditional finite element method simulations. These results indicate that ConvD-DeepONet is a promising tool for real-time subcutaneous temperature prediction, with the potential to enhance the safety and efficacy of cryolipolysis.</div></div>","PeriodicalId":23062,"journal":{"name":"Thermal Science and Engineering Progress","volume":"55 ","pages":"Article 102946"},"PeriodicalIF":5.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142356780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.tsep.2024.102945
Gerard Deepak , M. Parthiban , Srigitha.S. Nath , Badria Sulaiman Alfurhood , B. Mouleswararao , V Ravi Kishore
This paper proposes a novel approach for realising zero-defect manufacturing by integrating AI-based thermal modelling to perform multi-stage process, product, and system optimisation in complex manufacturing chains. It integrates advanced thermal simulation and sensor data feed in real-time as a multistage thermal prediction and management system via machine learning algorithms. This framework seeks to predict thermal behaviour using a combination of convolutional neural networks (CNNs), long short-term memory (LSTM) networks, and graph neural networks (GNNs) for encoding, predicting, and learning the spatial, temporal, and interactive thermal behaviour, respectively. It further embeds finite element analysis (FEA) simulations for high-fidelity thermal predictions using data fusion through Kalman filters. This helps obtain the optimal estimates of thermal states from sensor measurements involving different types of sensors and the characteristics of signals. A multistage multimodal optimization framework involves genetic algorithms (GA) for global thermal parameter optimisation, reinforcement learning (RL) for multi-stage dynamic process control optimisation, and multi-agent systems (MAS) for coordinated multi-stage multi-objective balance embedded in a digital twin architecture. Evaluation results show that the effectiveness of the proposed system in improving the overall production efficiency is 33%, reducing defects is 47%, and reducing energy utilisation is 22%, when compared to the current de facto approaches. There is also a 38% improvement in predictive capability in preventing, detecting, and predicting of cross-stage process faults.
{"title":"Ai-enhanced thermal modeling for integrated process-product-system optimization in zero-defect manufacturing chains","authors":"Gerard Deepak , M. Parthiban , Srigitha.S. Nath , Badria Sulaiman Alfurhood , B. Mouleswararao , V Ravi Kishore","doi":"10.1016/j.tsep.2024.102945","DOIUrl":"10.1016/j.tsep.2024.102945","url":null,"abstract":"<div><div>This paper proposes a novel approach for realising zero-defect manufacturing by integrating AI-based thermal modelling to perform multi-stage process, product, and system optimisation in complex manufacturing chains. It integrates advanced thermal simulation and sensor data feed in real-time as a multistage thermal prediction and management system via machine learning algorithms. This framework seeks to predict thermal behaviour using a combination of convolutional neural networks (CNNs), long short-term memory (LSTM) networks, and graph neural networks (GNNs) for encoding, predicting, and learning the spatial, temporal, and interactive thermal behaviour, respectively. It further embeds finite element analysis (FEA) simulations for high-fidelity thermal predictions using data fusion through Kalman filters. This helps obtain the optimal estimates of thermal states from sensor measurements involving different types of sensors and the characteristics of signals. A multistage multimodal optimization framework involves genetic algorithms (GA) for global thermal parameter optimisation, reinforcement learning (RL) for multi-stage dynamic process control optimisation, and multi-agent systems (MAS) for coordinated multi-stage multi-objective balance embedded in a digital twin architecture. Evaluation results show that the effectiveness of the proposed system in improving the overall production efficiency is 33%, reducing defects is 47%, and reducing energy utilisation is 22%, when compared to the current de facto approaches. There is also a 38% improvement in predictive capability in preventing, detecting, and predicting of cross-stage process faults.</div></div>","PeriodicalId":23062,"journal":{"name":"Thermal Science and Engineering Progress","volume":"55 ","pages":"Article 102945"},"PeriodicalIF":5.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142427326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present paper investigates different organic Rankine cycle (ORC) configurations, which can convert low-grade industrial waste heat streams (80–100 °C) into electricity. More specifically, the basic ORC, the reheated ORC, the ORC with a quasi-isothermal expander, and the trilateral flash cycle, are analyzed and compared. The quasi-isothermal expansion is achieved through heated oil injection at multiple stages inside the expander. Initially, these cycles are studied parametrically in terms of energy and exergy, considering the same available heat source load. The exergetic evaluation is enhanced through a thorough component-level exergetic analysis. Additionally, the cycles’ performance during a typical winter and a typical summer is examined. The final stage of this analysis includes the techno-economic investigation and comparison of the organic cycle designs. The results indicate that the ORC with quasi-isothermal expansion achieves the best thermodynamic performance compared to the other three designs. The largest calculated values of the net electrical power, the energy efficiency, and the exergy efficiency are 165.6 kW, 9.8 %, and 53.9 %, respectively. In parallel, the same cycle configuration is the most cost-effective, leading to a net present value equal to 2288 k€, and a payback period value of 1.3 years, when the operating hours are equal to 8000 per year. Hence, the ORC with quasi-isothermal expansion is found to be the most proper option for power production at low-temperature heat sources, while the reheated ORC performs marginally poorer from thermodynamic and techno-economic viewpoint.
{"title":"Energy, exergy, and economic comparison of ORC with quasi-isothermal expansion with other ORC designs for low-grade waste heat recovery","authors":"Panagiotis Lykas , Konstantinos Atsonios , Apostolos Gkountas , Panteleimon Bakalis , Dimitrios Manolakos , Panagiotis Grammelis , Grigorios Itskos , Nikolaos Nikolopoulos","doi":"10.1016/j.tsep.2024.103010","DOIUrl":"10.1016/j.tsep.2024.103010","url":null,"abstract":"<div><div>The present paper investigates different organic Rankine<!--> <!-->cycle (ORC) configurations, which can convert low-grade industrial waste heat streams (80–100 °C) into electricity. More specifically, the basic ORC, the reheated ORC, the ORC with<!--> <!-->a quasi-isothermal expander, and the trilateral flash cycle, are analyzed and compared. The quasi-isothermal expansion is achieved through heated oil injection at multiple stages inside the expander. Initially, these cycles are studied parametrically in terms of energy and exergy, considering the same available heat source load. The exergetic evaluation<!--> <!-->is enhanced through a thorough component-level exergetic analysis. Additionally, the cycles’<!--> <!-->performance during a typical winter and a typical summer<!--> <!-->is examined. The final stage of this analysis includes the techno-economic investigation and comparison of the organic cycle designs. The<!--> <!-->results indicate that the ORC with quasi-isothermal expansion achieves the best thermodynamic performance compared to the other three designs. The largest calculated values of the net electrical power, the energy efficiency, and the exergy efficiency are 165.6 kW, 9.8 %, and 53.9 %, respectively. In parallel, the same cycle configuration is the most cost-effective, leading to a net present value equal to 2288 k€, and a payback period value of 1.3 years, when the operating hours are equal to 8000 per year. Hence, the ORC with quasi-isothermal expansion is found to be the most proper option for power production at low-temperature heat sources, while the reheated ORC performs marginally poorer from thermodynamic and techno-economic viewpoint.</div></div>","PeriodicalId":23062,"journal":{"name":"Thermal Science and Engineering Progress","volume":"55 ","pages":"Article 103010"},"PeriodicalIF":5.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142658107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.tsep.2024.103002
Liang Li , Zhen Qian , Bo Niu , Xiubing Liang , Xiaojing Wang , Donghui Long
Electron transpiration cooling (ETC) is a spontaneous endothermic process that occurs during thermionic emission, which shows great potential in ultra-high-temperature thermal protection systems (TPS). Herein, we systematically analyze the main influencing factors on the cooling effect of ETC, such as incoming flow velocity, geometry, and material work function. A two-dimensional finite element model, based on Navier-Stokes equations coupled with the 11-species air reaction model and two-temperature model, is developed to solve the thermal interaction between ETC and the non-equilibrium flow field. Three operational thresholds for ETC are identified. Lower work functions enhance electron emission, thereby reducing wall temperature. With a 2.0 eV work function, ETC significantly outperforms blackbody radiation at 1360 K, and its cooling efficiency increases with temperature. For flow velocities above Mach 9.0, ETC is effective at the leading edge with a 2.4 eV work function and a 5 mm radius. However, it loses effectiveness with a 300 mm leading edge radius, even at Mach 16.0. Notably, at Mach 19.6, with a 2.0 eV work function and a 5 mm radius, ETC reduces surface temperature by up to 48.1 %. These findings highlight the considerable potential of ETC for applications in ultra-high-temperature TPS. These findings highlight the considerable potential of ETC for applications in ultra-high-temperature TPS.
{"title":"Impacting factors and operation thresholds of electron transpiration cooling-based thermal protection system","authors":"Liang Li , Zhen Qian , Bo Niu , Xiubing Liang , Xiaojing Wang , Donghui Long","doi":"10.1016/j.tsep.2024.103002","DOIUrl":"10.1016/j.tsep.2024.103002","url":null,"abstract":"<div><div>Electron transpiration cooling (ETC) is a spontaneous endothermic process that occurs during thermionic emission, which shows great potential in ultra-high-temperature thermal protection systems (TPS). Herein, we systematically analyze the main influencing factors on the cooling effect of ETC, such as incoming flow velocity, geometry, and material work function. A two-dimensional finite element model, based on Navier-Stokes equations coupled with the 11-species air reaction model and two-temperature model, is developed to solve the thermal interaction between ETC and the non-equilibrium flow field. Three operational thresholds for ETC are identified. Lower work functions enhance electron emission, thereby reducing wall temperature. With a 2.0 eV work function, ETC significantly outperforms blackbody radiation at 1360 K, and its cooling efficiency increases with temperature. For flow velocities above Mach 9.0, ETC is effective at the leading edge with a 2.4 eV work function and a 5 mm radius. However, it loses effectiveness with a 300 mm leading edge radius, even at Mach 16.0. Notably, at Mach 19.6, with a 2.0 eV work function and a 5 mm radius, ETC reduces surface temperature by up to 48.1 %. These findings highlight the considerable potential of ETC for applications in ultra-high-temperature TPS. These findings highlight the considerable potential of ETC for applications in ultra-high-temperature TPS.</div></div>","PeriodicalId":23062,"journal":{"name":"Thermal Science and Engineering Progress","volume":"55 ","pages":"Article 103002"},"PeriodicalIF":5.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142658039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.tsep.2024.102967
Kazuhiro Oda , Hiroki Oda , Yasushi Takase , Nao-Aki Noda
Heat-curing adhesives are widely used after being cured by heating to a temperature higher than room temperature. To evaluate the adhesive strength, therefore, it is necessary to consider both the thermal stress generated during heat curing and external loads such as tensile stress. Butt joint specimens are essential for evaluating tensile adhesive strength but also thermal strength. The interfacial strength can be discussed from the stress intensity factor (SIF) of a fictitious edge interfacial crack assumed at the interface end. This is because the SIF is controlled by the intensity of singular stress field (ISSF) at the crack-free interface end and a constant term associated with the thermal load. In this paper, a useful thermal SIF solution is proposed by superposing the SIF under tensile stress and the SIF under uniform interface stress associated with thermal loading. This general SIF expression provided under arbitrary material combination can be applied for predicting the tensile strength and critical temperature change without performing new FEM calculations. The usefulness of the expression is confirmed through the adhesive strength of Aluminum/Epoxy butt joint experimentally obtained. Once the critical SIF can be obtained from the tensile strength and the temperature change , the adhesive strength can be expressed as = constant of an assumed fictitious interface, and this can be used to predict critical for various temperature change and for various adhesive bondline thickness .
{"title":"Strength analysis due to thermal loading and tensile loading when metals are bonded by heat-curing adhesives","authors":"Kazuhiro Oda , Hiroki Oda , Yasushi Takase , Nao-Aki Noda","doi":"10.1016/j.tsep.2024.102967","DOIUrl":"10.1016/j.tsep.2024.102967","url":null,"abstract":"<div><div>Heat-curing adhesives are widely used after being cured by heating to a temperature higher than room temperature. To evaluate the adhesive strength, therefore, it is necessary to consider both the thermal stress generated during heat curing and external loads such as tensile stress. Butt joint specimens are essential for evaluating tensile adhesive strength but also thermal strength. The interfacial strength can be discussed from the stress intensity factor (SIF) of a fictitious edge interfacial crack assumed at the interface end. This is because the SIF is controlled by the intensity of singular stress field (ISSF) at the crack-free interface end and a constant term associated with the thermal load. In this paper, a useful thermal SIF solution is proposed by superposing the SIF under tensile stress and the SIF under uniform interface stress associated with thermal loading. This general SIF expression provided under arbitrary material combination can be applied for predicting the tensile strength <span><math><mrow><msub><mi>σ</mi><mi>c</mi></msub></mrow></math></span> and critical temperature change <span><math><mrow><mi>Δ</mi><mi>T</mi></mrow></math></span> without performing new FEM calculations. The usefulness of the expression is confirmed through the adhesive strength of Aluminum/Epoxy butt joint experimentally obtained. Once the critical SIF <span><math><mrow><msub><mi>K</mi><mrow><mn>1</mn><mi>C</mi></mrow></msub></mrow></math></span> can be obtained from the tensile strength <span><math><mrow><msub><mi>σ</mi><mi>c</mi></msub></mrow></math></span> and the temperature change <span><math><mrow><mi>Δ</mi><mi>T</mi></mrow></math></span>, the adhesive strength can be expressed as <span><math><mrow><msub><mi>K</mi><mrow><mn>1</mn><mi>C</mi></mrow></msub></mrow></math></span> = constant of an assumed fictitious interface, and this can be used to predict critical <span><math><mrow><msub><mi>σ</mi><mi>c</mi></msub></mrow></math></span> for various temperature change <span><math><mrow><mi>Δ</mi><mi>T</mi></mrow></math></span> and for various adhesive bondline thickness <span><math><mrow><mi>h</mi></mrow></math></span>.</div></div>","PeriodicalId":23062,"journal":{"name":"Thermal Science and Engineering Progress","volume":"55 ","pages":"Article 102967"},"PeriodicalIF":5.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142658109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.tsep.2024.102989
Hongxiang Lan , Lizhan Bai , Jingwei Fu , Shijin Nie , Huanfa Wang , Guiping Lin
Vapor chamber holds great application potential in the field of heat dissipation for high-power electronic devices. This study developed a novel vapor chamber using 3D-printing technology to enhance heat dissipation for compact electronic devices. The vapor chamber was constructed from aluminum alloy with a structural dimension of . In this work, the extended condensation structure of the vapor chamber was combined with an external cooling structure, resulting in a 729 % increase in the external heat dissipation area compared to the evaporation area in a limited space. Extensive experiments were conducted using deionized water as the working fluid under various cooling conditions and heat loads. The results showed that the vapor chamber was capable of maintaining a low thermal resistance at high power and high heat flux conditions, with a minimum thermal resistance of 0.087 °C/W when the heat load was 1000 W. At a cooling water flow rate of 0.1 L/s, the vapor chamber demonstrated the capacity to withstand a critical heat load of up to 1600 W, with the heat flux of 326 W/cm2. Compared to conventional vapor chambers, this novel vapor chamber is better able to achieve stable and efficient heat dissipation under high power and high heat flux conditions, especially in a limited space.
蒸气室在大功率电子设备散热领域具有巨大的应用潜力。本研究利用 3D 打印技术开发了一种新型蒸发腔，以增强紧凑型电子设备的散热性能。蒸发室由铝合金制成，结构尺寸为 60×60×30mm3。在这项工作中，蒸发室的扩展冷凝结构与外部冷却结构相结合，使外部散热面积比有限空间内的蒸发面积增加了 729%。在各种冷却条件和热负荷下，使用去离子水作为工作流体进行了大量实验。结果表明，蒸发室能够在高功率和高热通量条件下保持较低的热阻，当热负荷为 1000 W 时，最小热阻为 0.087 °C/W；在冷却水流速为 0.1 L/s 时，蒸发室能够承受高达 1600 W 的临界热负荷，热通量为 326 W/cm2。与传统的蒸气室相比，这种新型蒸气室更能在高功率和高热通量条件下实现稳定高效的散热，尤其是在有限的空间内。
{"title":"Experimental study on the thermal performance of a novel vapor chamber manufactured by 3D-printing technology","authors":"Hongxiang Lan , Lizhan Bai , Jingwei Fu , Shijin Nie , Huanfa Wang , Guiping Lin","doi":"10.1016/j.tsep.2024.102989","DOIUrl":"10.1016/j.tsep.2024.102989","url":null,"abstract":"<div><div>Vapor chamber holds great application potential in the field of heat dissipation for high-power electronic devices. This study developed a novel vapor chamber using 3D-printing technology to enhance heat dissipation for compact electronic devices. The vapor chamber was constructed from aluminum alloy with a structural dimension of <span><math><mrow><mn>60</mn><mo>×</mo><mn>60</mn><mo>×</mo><mn>30</mn><msup><mrow><mi>m</mi><mi>m</mi></mrow><mn>3</mn></msup></mrow></math></span>. In this work, the extended condensation structure of the vapor chamber was combined with an external cooling structure, resulting in a 729 % increase in the external heat dissipation area compared to the evaporation area in a limited space. Extensive experiments were conducted using deionized water as the working fluid under various cooling conditions and heat loads. The results showed that the vapor chamber was capable of maintaining a low thermal resistance at high power and high heat flux conditions, with a minimum thermal resistance of 0.087 °C/W when the heat load was 1000 W. At a cooling water flow rate of 0.1 L/s, the vapor chamber demonstrated the capacity to withstand a critical heat load of up to 1600 W, with the heat flux of 326 W/cm<sup>2</sup>. Compared to conventional vapor chambers, this novel vapor chamber is better able to achieve stable and efficient heat dissipation under high power and high heat flux conditions, especially in a limited space.</div></div>","PeriodicalId":23062,"journal":{"name":"Thermal Science and Engineering Progress","volume":"55 ","pages":"Article 102989"},"PeriodicalIF":5.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142658167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.tsep.2024.102988
F. Redoine , N. Belouaggadia , R. Lbibb , N. Sebaibi
Thermal Energy Storage using Latent Heat (TES-LH) systems offers a promising solution for mitigating the intermittency of solar energy and meeting growing energy demands. However, the low thermal conductivity of storage materials poses a challenge to their efficiency. This study introduces an innovative approach by incorporating hexagonal honeycomb annular fins into TES-LH devices to enhance heat transfer performance. CFD simulations were conducted using ANSYS Fluent to analyze a tubular TES-LH device equipped with these fins and a phase-change material (PCM). The parametric analysis focused on the effect of hexagonal cell thickness and length on PCM melting time. The new design was compared with conventional TES-LH units, and the influence of Heat Transfer Fluid (HTF) inlet parameters, such as temperature and flow rate, on PCM melting time was investigated. The results reveal that the honeycomb fin design significantly improves heat transfer, reducing PCM melting time from 840 s in the conventional setup to 216 s. This improvement is attributed to the increased surface area provided by the fins, enhancing the overall efficiency of the TES-LH system. Additionally, the impact of HTF inlet temperature and velocity on PCM melting time are highlighted. These findings demonstrate the potential for significant advancements in TES-LH systems, making them more efficient for real-world applications.
{"title":"Improving thermal energy storage system performance with innovative honeycomb fins","authors":"F. Redoine , N. Belouaggadia , R. Lbibb , N. Sebaibi","doi":"10.1016/j.tsep.2024.102988","DOIUrl":"10.1016/j.tsep.2024.102988","url":null,"abstract":"<div><div>Thermal Energy Storage using Latent Heat (TES-LH) systems offers a promising solution for mitigating the intermittency of solar energy and meeting growing energy demands. However, the low thermal conductivity of storage materials poses a challenge to their efficiency. This study introduces an innovative approach by incorporating hexagonal honeycomb annular fins into TES-LH devices to enhance heat transfer performance. CFD simulations were conducted using ANSYS Fluent to analyze a tubular TES-LH device equipped with these fins and a phase-change material (PCM). The parametric analysis focused on the effect of hexagonal cell thickness and length on PCM melting time. The new design was compared with conventional TES-LH units, and the influence of Heat Transfer Fluid (HTF) inlet parameters, such as temperature and flow rate, on PCM melting time was investigated. The results reveal that the honeycomb fin design significantly improves heat transfer, reducing PCM melting time from 840 s in the conventional setup to 216 s. This improvement is attributed to the increased surface area provided by the fins, enhancing the overall efficiency of the TES-LH system. Additionally, the impact of HTF inlet temperature and velocity on PCM melting time are highlighted. These findings demonstrate the potential for significant advancements in TES-LH systems, making them more efficient for real-world applications.</div></div>","PeriodicalId":23062,"journal":{"name":"Thermal Science and Engineering Progress","volume":"55 ","pages":"Article 102988"},"PeriodicalIF":5.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.tsep.2024.102997
Yuwen You , Yan Chen , Bin Yang , Chunmei Guo , Rong Gao , Yiwei Ma
The wet channel plate surface of indirect evaporative cooler (IEC) cannot be completely wet in actual working conditions, and the plate surface parameters of liquid film wetting rate and liquid film thickness are difficult to observe, and the lack of relevant experimental research and data support. Therefore, in this paper, machine vision technology will be used to experimentally investigate the wetting rate and liquid film thickness of the secondary side channel of the IEC, and the UDF interface program and the parameters of the original simulation model will be enhanced. The results show that the average and maximum errors of the first and second outlet temperatures of the corrected analytical model are reduced compared with the original model, and the average error is within 5% under different spray flow rates.
{"title":"Optimization of liquid film parameters of indirect evaporative cooling system based on machine vision","authors":"Yuwen You , Yan Chen , Bin Yang , Chunmei Guo , Rong Gao , Yiwei Ma","doi":"10.1016/j.tsep.2024.102997","DOIUrl":"10.1016/j.tsep.2024.102997","url":null,"abstract":"<div><div>The wet channel plate surface of indirect evaporative cooler (IEC) cannot be completely wet in actual working conditions, and the plate surface parameters of liquid film wetting rate and liquid film thickness are difficult to observe, and the lack of relevant experimental research and data support. Therefore, in this paper, machine vision technology will be used to experimentally investigate the wetting rate and liquid film thickness of the secondary side channel of the IEC, and the UDF interface program and the parameters of the original simulation model will be enhanced. The results show that the average and maximum errors of the first and second outlet temperatures of the corrected analytical model are reduced compared with the original model, and the average error is within 5% under different spray flow rates.</div></div>","PeriodicalId":23062,"journal":{"name":"Thermal Science and Engineering Progress","volume":"55 ","pages":"Article 102997"},"PeriodicalIF":5.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142658108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.tsep.2024.102936
Mona Gad , Bo Gao , Dan Ni , Wenbin Zhang , Longlong Yan , Ning Zhang
Centrifugal pumps are essential in various industrial applications, including renewable energy. To maximize the pump’s overall performance, estimating flow energy losses (FEL) is crucial. However, due to internal flow complexity, it is necessary to employ new methods and approaches to better understand FEL mechanisms. This study uses entropy generation theory to investigate the relationship between FEL and various flow patterns in all pump hydraulic components. Numerical simulations were conducted using a 3-dimensional incompressible unsteady flow at four different flow coefficients. The delayed detached eddy simulation (DDES) model was used, and the results showed good agreement with experimental data compared to the SST k-w model. Emphasis was given to the flow energy losses and the relative and absolute velocity distribution in the impeller and diffuser components at various flow coefficients. Flow energy losses primarily occur in the impeller (70%) followed by the diffuser (23%). Impeller losses are concentrated at the outlet region due to the wake-jet phenomena (28.6%), splitter blades region (15.3%), and impeller’s leading edge (LE) (10.7%). Vaned diffuser losses occur in the vanless zone (stator-rotor interaction) and near leading/trailing edges. Moreover, wall shear stress and the significant relative velocity gradient near the walls of the impeller and diffuser blades are the main contributors to the FEL in this region. This study provides insights into a better understanding of FEL mechanisms and highlights areas for improving pump performance.
离心泵在包括可再生能源在内的各种工业应用中至关重要。为了最大限度地提高泵的整体性能，估算流动能量损失（FEL）至关重要。然而，由于内部流动的复杂性，有必要采用新的方法和途径来更好地了解 FEL 机制。本研究采用熵生成理论来研究 FEL 与所有泵液压元件中各种流动模式之间的关系。采用四种不同流量系数的三维不可压缩非稳定流进行了数值模拟。与 SST k-w 模型相比，延迟分离涡模拟 (DDES) 模型的结果与实验数据显示出良好的一致性。重点研究了不同流量系数下的流动能量损失以及叶轮和扩散器部件中的相对速度和绝对速度分布。流动能量损失主要发生在叶轮（70%），其次是扩散器（23%）。叶轮的损失主要集中在出口区域（28.6%）、分流器叶片区域（15.3%）和叶轮前缘（10.7%）。无叶片扩散器损失发生在无叶片区（定转子相互作用）和前缘/后缘附近。此外，叶轮和扩散器叶片壁面附近的壁面剪应力和显著的相对速度梯度是造成该区域 FEL 的主要原因。这项研究为更好地理解 FEL 机制提供了见解，并突出了提高泵性能的领域。
{"title":"Influence of internal flow structure on flow energy losses in a centrifugal pump with splitter blades using entropy generation theory","authors":"Mona Gad , Bo Gao , Dan Ni , Wenbin Zhang , Longlong Yan , Ning Zhang","doi":"10.1016/j.tsep.2024.102936","DOIUrl":"10.1016/j.tsep.2024.102936","url":null,"abstract":"<div><div>Centrifugal pumps are essential in various industrial applications, including renewable energy. To maximize the pump’s overall performance, estimating flow energy losses (FEL) is crucial. However, due to internal flow complexity, it is necessary to employ new methods and approaches to better understand FEL mechanisms. This study uses entropy generation theory to investigate the relationship between FEL and various flow patterns in all pump hydraulic components. Numerical simulations were conducted using a 3-dimensional incompressible unsteady flow at four different flow coefficients. The delayed detached eddy simulation (DDES) model was used, and the results showed good agreement with experimental data compared to the SST k-<em>w</em> model. Emphasis was given to the flow energy losses and the relative and absolute velocity distribution in the impeller and diffuser components at various flow coefficients. Flow energy losses primarily occur in the impeller (70%) followed by the diffuser (23%). Impeller losses are concentrated at the outlet region due to the wake-jet phenomena (28.6%), splitter blades region (15.3%), and impeller’s leading edge (LE) (10.7%). Vaned diffuser losses occur in the vanless zone (stator-rotor interaction) and near leading/trailing edges.<!--> <!-->Moreover, wall shear stress and the significant relative velocity gradient near the walls of the impeller and diffuser blades are the main contributors to the FEL in this region. This study provides insights into a better understanding of FEL mechanisms and highlights areas for improving pump performance.</div></div>","PeriodicalId":23062,"journal":{"name":"Thermal Science and Engineering Progress","volume":"55 ","pages":"Article 102936"},"PeriodicalIF":5.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142356839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.tsep.2024.102919
Xingxing Ma , Jinfeng Wang , Jing Xie , Hao Xu , Guosen Ye , Jilin Jiang , Xinrong Han
Zero superheat degree at the outlet of the evaporator is important for the efficient operation of refrigeration systems. Though it is the theoretically possible to control zero superheat degree to zero, it is rare to find publications in this area. In this study, the effects of the electronic expansion valve and the pressure regulation valve on zero superheat control investigated experimentally. The results indicate that when the control value of degree was set to zero, the electronic expansion valve could not achieve accurate control. The evaporation pressure and temperature kept changing, and the refrigerant flow state at the outlet of the evaporator alternated dramatically at the same time. There was a significant appearance of liquid refrigerant at the evaporator outlet. However, the stable control of zero superheat could be achieved when using the Electronic Expansion Valve and Pressure Regulation Valve Common Control Method (EPCCM). The combination of the pressure regulation valve and the Electronic Expansion Valve enables independent control of the evaporation pressure and the superheat degree at the outlet of the evaporator, which makes it possible to control the superheat of the refrigerant at the outlet of the evaporator to zero. The experiment results also show that the EPCCM has remarkable effect on zero superheat control, as well as safe and stable operation of the refrigeration systems.
{"title":"Optimization of zero superheat control at the evaporator outlet: Application of EXV and pressure regulation valve","authors":"Xingxing Ma , Jinfeng Wang , Jing Xie , Hao Xu , Guosen Ye , Jilin Jiang , Xinrong Han","doi":"10.1016/j.tsep.2024.102919","DOIUrl":"10.1016/j.tsep.2024.102919","url":null,"abstract":"<div><div>Zero superheat degree at the outlet of the evaporator is important for the efficient operation of refrigeration systems. Though it is the theoretically possible to control zero superheat degree to zero, it is rare to find publications in this area. In this study, the effects of the electronic expansion valve and the pressure regulation valve on zero superheat control investigated experimentally. The results indicate that when the control value of degree was set to zero, the electronic expansion valve could not achieve accurate control. The evaporation pressure and temperature kept changing, and the refrigerant flow state at the outlet of the evaporator alternated dramatically at the same time. There was a significant appearance of liquid refrigerant at the evaporator outlet. However, the stable control of zero superheat could be achieved when using the Electronic Expansion Valve and Pressure Regulation Valve Common Control Method (EPCCM). The combination of the pressure regulation valve and the Electronic Expansion Valve enables independent control of the evaporation pressure and the superheat degree at the outlet of the evaporator, which makes it possible to control the superheat of the refrigerant at the outlet of the evaporator to zero. The experiment results also show that the EPCCM has remarkable effect on zero superheat control, as well as safe and stable operation of the refrigeration systems.</div></div>","PeriodicalId":23062,"journal":{"name":"Thermal Science and Engineering Progress","volume":"55 ","pages":"Article 102919"},"PeriodicalIF":5.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142356779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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