Case Studies in Thermal Engineering最新文献_第2页

Dynamic characteristics of a two-phase mechanically pumped cooling loop for avionics

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2025-02-03 DOI: 10.1016/j.csite.2025.105830

Shaohuan Qi, Zhaohao Xu, Jiale Wang, Yu Xu

Given the varying flight conditions and mission requirements that affect aircraft cold sources and heat loads, it is crucial to investigate the dynamic behavior of a two-phase mechanically pumped cooling loop (MPCL) for avionics. Here, an experimental MPCL system charged with R134a was established, and its performance was evaluated under cold source temperatures of 16–46 °C and heat fluxes of 50–150 kW/m². When the cold source temperature varies, the heating wall temperature and pressure drop are 33.7–60.0 °C and 78.0−119.6 kPa for unadjustable pump mode, and they are 34.1–60.0 °C and 59.6−124.6 kPa for adjustable pump mode. When heat load starts, the heating wall temperature and pressure drop rapid rise, and then stabilize. For low temperature start-up, the heating wall temperature is lower, but the pressure drop is usually higher compared to high temperature start-up. When heat load jumps, heating wall temperature and pressure drop rise and then stabilize regardless of pump mode. The pump mode has a minor impact on the heating wall temperature, but the pressure drop is greater in adjustable mode than in unadjustable mode. The findings indicate the designed MPCL can always tend to be stable when the cold source or heat load change.

{"title":"Dynamic characteristics of a two-phase mechanically pumped cooling loop for avionics","authors":"Shaohuan Qi, Zhaohao Xu, Jiale Wang, Yu Xu","doi":"10.1016/j.csite.2025.105830","DOIUrl":"10.1016/j.csite.2025.105830","url":null,"abstract":"<div><div>Given the varying flight conditions and mission requirements that affect aircraft cold sources and heat loads, it is crucial to investigate the dynamic behavior of a two-phase mechanically pumped cooling loop (MPCL) for avionics. Here, an experimental MPCL system charged with R134a was established, and its performance was evaluated under cold source temperatures of 16–46 °C and heat fluxes of 50–150 kW/m<sup>2</sup>. When the cold source temperature varies, the heating wall temperature and pressure drop are 33.7–60.0 °C and 78.0−119.6 kPa for unadjustable pump mode, and they are 34.1–60.0 °C and 59.6−124.6 kPa for adjustable pump mode. When heat load starts, the heating wall temperature and pressure drop rapid rise, and then stabilize. For low temperature start-up, the heating wall temperature is lower, but the pressure drop is usually higher compared to high temperature start-up. When heat load jumps, heating wall temperature and pressure drop rise and then stabilize regardless of pump mode. The pump mode has a minor impact on the heating wall temperature, but the pressure drop is greater in adjustable mode than in unadjustable mode. The findings indicate the designed MPCL can always tend to be stable when the cold source or heat load change.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"67 ","pages":"Article 105830"},"PeriodicalIF":6.4,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143257811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental study on the solar heating and night sky radiative cooling properties of biochar

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2025-02-03 DOI: 10.1016/j.csite.2025.105832

Haiwei Xie, Jianyun Luo, Yan Zhang, Jiajuan Yan, Yuhao Qing

Daytime solar heating and nighttime radiative cooling are of great significance to global energy conservation and carbon neutrality because of their low cost, zero energy consumption and environmentally friendly characteristics. In this study, a new radiation material, walnut shell biochar (WBS), was proposed and its performance in daytime solar heating and nighttime radiative cooling was studied. The experimental results indicate that WBS exhibits a maximum absorption rate of 95.93 % within the solar radiation spectrum, along with an average emissivity of 92.45 % in the atmospheric transmission window. When utilizing a low-density polyethylene film cover plate with a thickness of 10 μm and employing 50 mesh of WBS, the combined effect of daytime solar heating and nighttime radiative cooling is optimized. Under conditions where the solar radiation intensity reaches 750 W/m², the surface temperature of WBS is observed to be 63.3 °C higher than that of the ambient temperature. Conversely, on clear nights, this surface temperature drops to be 15.5 °C lower than that of its surroundings. This research provides valuable technical support for developing integrated processes that leverage both daytime heating and nighttime radiative cooling.

{"title":"Experimental study on the solar heating and night sky radiative cooling properties of biochar","authors":"Haiwei Xie, Jianyun Luo, Yan Zhang, Jiajuan Yan, Yuhao Qing","doi":"10.1016/j.csite.2025.105832","DOIUrl":"10.1016/j.csite.2025.105832","url":null,"abstract":"<div><div>Daytime solar heating and nighttime radiative cooling are of great significance to global energy conservation and carbon neutrality because of their low cost, zero energy consumption and environmentally friendly characteristics. In this study, a new radiation material, walnut shell biochar (WBS), was proposed and its performance in daytime solar heating and nighttime radiative cooling was studied. The experimental results indicate that WBS exhibits a maximum absorption rate of 95.93 % within the solar radiation spectrum, along with an average emissivity of 92.45 % in the atmospheric transmission window. When utilizing a low-density polyethylene film cover plate with a thickness of 10 μm and employing 50 mesh of WBS, the combined effect of daytime solar heating and nighttime radiative cooling is optimized. Under conditions where the solar radiation intensity reaches 750 W/m<sup>2</sup>, the surface temperature of WBS is observed to be 63.3 °C higher than that of the ambient temperature. Conversely, on clear nights, this surface temperature drops to be 15.5 °C lower than that of its surroundings. This research provides valuable technical support for developing integrated processes that leverage both daytime heating and nighttime radiative cooling.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"67 ","pages":"Article 105832"},"PeriodicalIF":6.4,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143349450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Thermodynamic and economic analysis, optimization of SOFC/GT/SCO2/ORC hybrid power systems for methanol reforming-powered ships with carbon capture

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2025-02-03 DOI: 10.1016/j.csite.2025.105840

Shouguang Yao , Xuan Yan , Minjie Xia , Chuang Wang , Shaofan Wang

To realize the efficient use of energy and reduction of emissions of the power system of ocean-going vessels, a 25,000-ton chemical ship is used as the subject of this study. A hybrid power system containing carbon capture based on methanol external reforming of solid oxide fuel cell coupled with gas turbine is proposed, further to achieve efficient energy use and reduce carbon emissions, the power system combines a supercritical CO₂ cycle with an organic Rankine cycle in order to optimize the utilization of waste heat, and chemical absorption method for carbon capture. The proposed novel power system is analyzed for the impact of important factors of each system on performance of the system, and thermodynamic and economic analyses and evaluations are carried out. Ultimately, a genetic algorithm-based approach was employed to optimize the system's performance through multi-objective optimization, aiming for the best possible outcome. The optimized outcome shows that the system's net output power has reached 4743.81 kW, which fully satisfies the power requirements of the target vessel. Additionally, it achieves a carbon capture rate of 81.52 %, an energy efficiency of 60.56 %, and the cost of electricity production is 0.08727 $/kWh. The system realizes excellent thermodynamic performance and economy.

{"title":"Thermodynamic and economic analysis, optimization of SOFC/GT/SCO2/ORC hybrid power systems for methanol reforming-powered ships with carbon capture","authors":"Shouguang Yao , Xuan Yan , Minjie Xia , Chuang Wang , Shaofan Wang","doi":"10.1016/j.csite.2025.105840","DOIUrl":"10.1016/j.csite.2025.105840","url":null,"abstract":"<div><div>To realize the efficient use of energy and reduction of emissions of the power system of ocean-going vessels, a 25,000-ton chemical ship is used as the subject of this study. A hybrid power system containing carbon capture based on methanol external reforming of solid oxide fuel cell coupled with gas turbine is proposed, further to achieve efficient energy use and reduce carbon emissions, the power system combines a supercritical CO<sub>2</sub> cycle with an organic Rankine cycle in order to optimize the utilization of waste heat, and chemical absorption method for carbon capture. The proposed novel power system is analyzed for the impact of important factors of each system on performance of the system, and thermodynamic and economic analyses and evaluations are carried out. Ultimately, a genetic algorithm-based approach was employed to optimize the system's performance through multi-objective optimization, aiming for the best possible outcome. The optimized outcome shows that the system's net output power has reached 4743.81 kW, which fully satisfies the power requirements of the target vessel. Additionally, it achieves a carbon capture rate of 81.52 %, an energy efficiency of 60.56 %, and the cost of electricity production is 0.08727 $/kWh. The system realizes excellent thermodynamic performance and economy.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"67 ","pages":"Article 105840"},"PeriodicalIF":6.4,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143257810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental investigation and scenario-based optimization of energy flexibility in embedded radiant cooling systems

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2025-02-03 DOI: 10.1016/j.csite.2025.105835

Yun Xie , Yanxue Li , Hongshe Cui

This study experimentally demonstrates the precooling flexibility of radiant cooling panels embedded into the envelope. The results show that a 3-h precooling period provides approximately 2.5 h of recovery time, allowing the indoor temperature to rise steadily to the upper limit with relatively low energy consumption. This confirms the effectiveness of the proposed cooling system in load shifting without compromising indoor comfort. Additionally, different thermal models were developed and compared using measured data. The state-space model was identified as the most accurate and reliable model for capturing system thermodynamics. Scenario-based Model Predictive Control (MPC) energy managements were designed and evaluated optimized results. Compared to the measured results, the scenario optimized for minimum energy consumption reduced total energy use by 17.8 %. Scenarios responding to Time-of-Use (TOU) pricing and photovoltaics (PV) generation reduced energy costs by 31.4 % and 29.8 %, respectively, with the latter achieving 93.4 % PV self-consumption. Proposed energy management strategies maintained indoor temperatures within an acceptable thermal comfort range, with an average temperature difference of less than 0.1 °C during the radiant cooling system's operation. The effective reduction in energy costs without compromising thermal comfort highlights the potential of MPC in optimizing the flexibility by leveraging dynamic price and PV generation.

{"title":"Experimental investigation and scenario-based optimization of energy flexibility in embedded radiant cooling systems","authors":"Yun Xie , Yanxue Li , Hongshe Cui","doi":"10.1016/j.csite.2025.105835","DOIUrl":"10.1016/j.csite.2025.105835","url":null,"abstract":"<div><div>This study experimentally demonstrates the precooling flexibility of radiant cooling panels embedded into the envelope. The results show that a 3-h precooling period provides approximately 2.5 h of recovery time, allowing the indoor temperature to rise steadily to the upper limit with relatively low energy consumption. This confirms the effectiveness of the proposed cooling system in load shifting without compromising indoor comfort. Additionally, different thermal models were developed and compared using measured data. The state-space model was identified as the most accurate and reliable model for capturing system thermodynamics. Scenario-based Model Predictive Control (MPC) energy managements were designed and evaluated optimized results. Compared to the measured results, the scenario optimized for minimum energy consumption reduced total energy use by 17.8 %. Scenarios responding to Time-of-Use (TOU) pricing and photovoltaics (PV) generation reduced energy costs by 31.4 % and 29.8 %, respectively, with the latter achieving 93.4 % PV self-consumption. Proposed energy management strategies maintained indoor temperatures within an acceptable thermal comfort range, with an average temperature difference of less than 0.1 °C during the radiant cooling system's operation. The effective reduction in energy costs without compromising thermal comfort highlights the potential of MPC in optimizing the flexibility by leveraging dynamic price and PV generation.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"67 ","pages":"Article 105835"},"PeriodicalIF":6.4,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143372258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A multi-criteria optimization for a radial heat sink with semicircular fins based on the design of experiments approach 基于实验设计方法的半圆翅片径向散热器多准则优化

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2025-02-01 DOI: 10.1016/j.csite.2024.105727

Yousif Hashim Hussein , Tahseen Ahmad Tahseen , Abdulrazzak Akroot , M.A.H. Mithu , Ammar M. Abdulateef

Radial fins play a crucial role in enhancing energy efficiency and supporting sustainable industrial practices by optimizing heat transfer, aligning with the Sustainable Development Goals (SDGs). Addressing the need for high-efficiency systems to reduce greenhouse gas emissions, this study highlights the importance of optimizing factors in a General Factorial Design (GFD). Factors were coded and scaled within the range of +1 to −1, accounting for variations in the units of independent variables. This study utilized the Nusselt number and thermal resistance, along with an effective regression analysis, to develop a novel predictive model. Key performance indicators included R², adjusted R², predicted R², coefficient of variation (CV), and parameter separation from the best-fit results. The proposed model demonstrated remarkable accuracy in predicting the Nusselt number, with values of R², predicted R², adjusted R², and CV at 98.15 %, 97.08 %, 94.87 %, and 2.44 %, respectively. For thermal resistance, the corresponding values were 97.91 % for predicted R², 96.70 % for adjusted R², 94.21 % for CV, and 3.33 % for parameter separation. Therefore, it is evident that the proposed model is highly accurate in predicting semicircular radial heat sink performance, offering a robust tool for future heat sink designs and sustainable thermal management systems.

径向翅片通过优化传热，在提高能源效率和支持可持续工业实践方面发挥着至关重要的作用，符合可持续发展目标（sdg）。为了解决对高效系统减少温室气体排放的需求，本研究强调了在一般析因设计（GFD）中优化因素的重要性。因子被编码并在+1到- 1的范围内缩放，考虑到自变量单位的变化。本研究利用努塞尔数和热阻，结合有效的回归分析，建立了一种新的预测模型。关键绩效指标包括R2、调整R2、预测R2、变异系数（CV）、参数与最佳拟合结果的分离。该模型预测Nusselt数的准确率显著，R2、预测R2、调整R2和CV值分别为98.15%、97.08%、94.87%和2.44%。热阻预测R2值为97.91%，调整R2值为96.70%，CV值为94.21%，参数分离值为3.33%。因此，很明显，所提出的模型在预测半圆径向散热器性能方面是非常准确的，为未来的散热器设计和可持续的热管理系统提供了一个强大的工具。

{"title":"A multi-criteria optimization for a radial heat sink with semicircular fins based on the design of experiments approach","authors":"Yousif Hashim Hussein , Tahseen Ahmad Tahseen , Abdulrazzak Akroot , M.A.H. Mithu , Ammar M. Abdulateef","doi":"10.1016/j.csite.2024.105727","DOIUrl":"10.1016/j.csite.2024.105727","url":null,"abstract":"<div><div>Radial fins play a crucial role in enhancing energy efficiency and supporting sustainable industrial practices by optimizing heat transfer, aligning with the Sustainable Development Goals (SDGs). Addressing the need for high-efficiency systems to reduce greenhouse gas emissions, this study highlights the importance of optimizing factors in a General Factorial Design (GFD). Factors were coded and scaled within the range of +1 to −1, accounting for variations in the units of independent variables. This study utilized the Nusselt number and thermal resistance, along with an effective regression analysis, to develop a novel predictive model. Key performance indicators included R<sup>2</sup>, adjusted R<sup>2</sup>, predicted R<sup>2</sup>, coefficient of variation (CV), and parameter separation from the best-fit results. The proposed model demonstrated remarkable accuracy in predicting the Nusselt number, with values of R<sup>2</sup>, predicted R<sup>2</sup>, adjusted R<sup>2</sup>, and CV at 98.15 %, 97.08 %, 94.87 %, and 2.44 %, respectively. For thermal resistance, the corresponding values were 97.91 % for predicted R<sup>2</sup>, 96.70 % for adjusted R<sup>2</sup>, 94.21 % for CV, and 3.33 % for parameter separation. Therefore, it is evident that the proposed model is highly accurate in predicting semicircular radial heat sink performance, offering a robust tool for future heat sink designs and sustainable thermal management systems.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"66 ","pages":"Article 105727"},"PeriodicalIF":6.4,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142912334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A novel hybrid system consisting of direct ammonia solid oxide fuel cell, gas turbine and dual-loop organic rankine cycle (DA-SOFC-GT-ORC): Multi-objective optimization and performance analysis 一种由直接氨固体氧化物燃料电池、燃气轮机和双回路有机朗肯循环（DA-SOFC-GT-ORC）组成的新型混合动力系统：多目标优化与性能分析

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2025-02-01 DOI: 10.1016/j.csite.2024.105699

Weihua Cai , Hao Zhang , Xunjian Che , Zhongnong Zhang , Qian Li , Benan Cai , Kexin Liu

Ammonia is a hydrogen carrier that emits no carbon and benefits from a well-established infrastructure for production, storage, and transport, making it an increasingly favored clean fuel. This paper introduces the first exploration and analysis of a Direct Ammonia fueled Solid Oxide Fuel Cell and Gas Turbine system with a Dual-Loop Organic Rankine Cycle (DA-SOFC-GT-ORC). We performed a multi-objective optimization for this system, with emphasis on enhancing both efficiency and economic feasibility. Under optimized conditions, the system achieves an exergy efficiency of 60.45 %, which is 10.64 % higher than that of a methane-fueled system. We analyze factors affecting system performance, including fuel flow rate, air flow rate, and fuel utilization rate. The results demonstrate that elevated temperature and pressure at the SOFC inlet improve system performance. The maximum exergy destruction is observed in the SOFC, heat exchangers, and gas turbine. Adding more cells improves system performance but also increases overall costs, with the minimum production cost per electrical unit achieved at 45,000 cells. The economic efficiency is marginally affected by air flow rate, yet considerably by fuel flow rate. For minor fluctuations in power demand, it is recommended to adjust the air flow rate to maintain high economic efficiency.

氨是一种不排放碳的氢载体，并且得益于完善的生产、储存和运输基础设施，使其成为越来越受欢迎的清洁燃料。本文首次对双回路有机朗肯循环（DA-SOFC-GT-ORC）直接氨燃料固体氧化物燃料电池和燃气轮机系统进行了探索和分析。我们对该系统进行了多目标优化，重点是提高效率和经济可行性。在优化条件下，系统的火用效率为60.45%，比以甲烷为燃料的系统高10.64%。分析了影响系统性能的因素，包括燃油流量、空气流量和燃油利用率。结果表明，提高SOFC入口温度和压力可以改善系统性能。在SOFC、热交换器和燃气轮机中观察到最大的火用破坏。增加更多的电池可以提高系统性能，但也会增加总体成本，每个电气单元的最低生产成本达到45,000个电池。经济效率受空气流量的影响很小，但受燃油流量的影响很大。对于电力需求波动较小的情况，建议调整风量，保持较高的经济效益。

{"title":"A novel hybrid system consisting of direct ammonia solid oxide fuel cell, gas turbine and dual-loop organic rankine cycle (DA-SOFC-GT-ORC): Multi-objective optimization and performance analysis","authors":"Weihua Cai , Hao Zhang , Xunjian Che , Zhongnong Zhang , Qian Li , Benan Cai , Kexin Liu","doi":"10.1016/j.csite.2024.105699","DOIUrl":"10.1016/j.csite.2024.105699","url":null,"abstract":"<div><div>Ammonia is a hydrogen carrier that emits no carbon and benefits from a well-established infrastructure for production, storage, and transport, making it an increasingly favored clean fuel. This paper introduces the first exploration and analysis of a Direct Ammonia fueled Solid Oxide Fuel Cell and Gas Turbine system with a Dual-Loop Organic Rankine Cycle (DA-SOFC-GT-ORC). We performed a multi-objective optimization for this system, with emphasis on enhancing both efficiency and economic feasibility. Under optimized conditions, the system achieves an exergy efficiency of 60.45 %, which is 10.64 % higher than that of a methane-fueled system. We analyze factors affecting system performance, including fuel flow rate, air flow rate, and fuel utilization rate. The results demonstrate that elevated temperature and pressure at the SOFC inlet improve system performance. The maximum exergy destruction is observed in the SOFC, heat exchangers, and gas turbine. Adding more cells improves system performance but also increases overall costs, with the minimum production cost per electrical unit achieved at 45,000 cells. The economic efficiency is marginally affected by air flow rate, yet considerably by fuel flow rate. For minor fluctuations in power demand, it is recommended to adjust the air flow rate to maintain high economic efficiency.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"66 ","pages":"Article 105699"},"PeriodicalIF":6.4,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142912345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Study on the impact parameters of convective heat transfer in industrial-scale Siemens reactor 工业规模西门子反应器对流换热影响参数研究

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2025-02-01 DOI: 10.1016/j.csite.2024.105694

Xingping Yuan , Dan Zhao , Yanqing Hou , Ni Yang , Wenhui Ma , Fengyang Chen , Gang Xie

In industrial-scale Siemens reactors, convective heat transfer (CHT) plays a crucial role in regulating the uniformity of the reactor's temperature distribution and ensuring the quality of the polysilicon products. This study developed a forced CHT model for a 12-pair silicon rod industrial-scale Siemens reactor. The effects of operating parameters (inlet gas temperature, inlet gas velocity and silicon rod surface temperature) and geometrical parameters (diameter and number of silicon rods) on the CHT coefficient were analyzed, and the results indicate that the inlet gas velocity and the diameter of the silicon rods had the greatest effect on the CHT coefficient, which fluctuated up to. 85.5 W m⁻² K⁻¹. Furthermore, this study also considered the interactions between these factors and derived a correlation equation that characterizes the CHT behavior in the reactor. The equation was validated using production data from a 24-pair silicon rod industrial-scale Siemens reactor, with an error of only 7.6 %, demonstrating the reliability of the model. Consequently, the established forced CHT model and correlation equation can effectively predict CHT in industrial-scale Siemens reactors. This study provides a valuable tool for optimizing reactor design and operation, ultimately contributing to the reduction of silica fines formation and energy consumption during the production process.

在工业规模的西门子反应器中，对流换热（CHT）在调节反应器温度分布均匀性和保证多晶硅产品质量方面起着至关重要的作用。本研究开发了一个12对硅棒工业规模西门子反应器的强制CHT模型。分析了操作参数（进口气体温度、进口气体速度和硅棒表面温度）和几何参数（硅棒直径和数量）对CHT系数的影响，结果表明，进口气体速度和硅棒直径对CHT系数的影响最大，波动幅度可达。85.5 W m - 2 K - 1此外，本研究还考虑了这些因素之间的相互作用，并推导了表征反应器中CHT行为的相关方程。利用西门子工业规模的24对硅棒反应器的生产数据验证了该方程，误差仅为7.6%，证明了该模型的可靠性。因此，所建立的强制CHT模型和相关方程可以有效地预测工业规模西门子反应器的CHT。该研究为优化反应器设计和操作提供了有价值的工具，最终有助于减少生产过程中二氧化硅颗粒的形成和能源消耗。

{"title":"Study on the impact parameters of convective heat transfer in industrial-scale Siemens reactor","authors":"Xingping Yuan , Dan Zhao , Yanqing Hou , Ni Yang , Wenhui Ma , Fengyang Chen , Gang Xie","doi":"10.1016/j.csite.2024.105694","DOIUrl":"10.1016/j.csite.2024.105694","url":null,"abstract":"<div><div>In industrial-scale Siemens reactors, convective heat transfer (CHT) plays a crucial role in regulating the uniformity of the reactor's temperature distribution and ensuring the quality of the polysilicon products. This study developed a forced CHT model for a 12-pair silicon rod industrial-scale Siemens reactor. The effects of operating parameters (inlet gas temperature, inlet gas velocity and silicon rod surface temperature) and geometrical parameters (diameter and number of silicon rods) on the CHT coefficient were analyzed, and the results indicate that the inlet gas velocity and the diameter of the silicon rods had the greatest effect on the CHT coefficient, which fluctuated up to. 85.5 W m⁻<sup>2</sup> K⁻<sup>1</sup>. Furthermore, this study also considered the interactions between these factors and derived a correlation equation that characterizes the CHT behavior in the reactor. The equation was validated using production data from a 24-pair silicon rod industrial-scale Siemens reactor, with an error of only 7.6 %, demonstrating the reliability of the model. Consequently, the established forced CHT model and correlation equation can effectively predict CHT in industrial-scale Siemens reactors. This study provides a valuable tool for optimizing reactor design and operation, ultimately contributing to the reduction of silica fines formation and energy consumption during the production process.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"66 ","pages":"Article 105694"},"PeriodicalIF":6.4,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142912347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Structural optimization of solar chimney system based on heat efficiency and flow velocity: Numerical and Experimental studies 基于热效率和流速的太阳能烟囱系统结构优化：数值与实验研究

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2025-02-01 DOI: 10.1016/j.csite.2024.105714

Jing Jia , Jing Nie , Hao Su , Jin-Chen XU , Xinyao Ruan , Wei Gao

This study focuses on enhancing the heat collection performance of solar chimney systems (SCS). The effect of various sizing parameters on the square SCS with a single side inlet is investigated through experimental and numerical simulations for optimization. The experimental results demonstrate significant variation in temperature uniformity among absorbers made from different materials. The composite absorber consisting of bamboo glue board, aluminum, sand, and black high-density polyethylene foam board exhibits excellent temperature uniformity. Optimization is performed with heat collection efficiency and chimney inlet fluid velocity as objective functions. The results indicate that adjusting the transparent cover inclination angle and chimney dispersion angle significantly enhances heat collection efficiency. Specifically, the SCS achieves a heat collection efficiency of 42.54 % when the inclination angle is set to 10° and the chimney dispersion angle is set to 1°. The chimney inlet fluid velocity of the SCS varies with different chimney dispersion angles at the same transparent cover inclination. At a dispersion angle of 2°, the velocity reaches a maximum of 2.090 m/s. Due to the large transparent cover area of the SCS, it is recommended to integrate the SCS with buildings and agriculture to achieve zero energy consumption and promote sustainable agriculture.

本文主要研究如何提高太阳能烟囱系统的集热性能。通过实验和数值模拟研究了不同尺寸参数对单侧进气道方形超细管的影响。实验结果表明，不同材料制成的吸收体在温度均匀性上存在显著差异。由竹胶板、铝、砂和黑色高密度聚乙烯泡沫板组成的复合吸收体具有良好的温度均匀性。以集热效率和烟囱入口流体速度为目标函数进行优化。结果表明，调节透明罩倾角和烟囱分散角可显著提高集热效率。其中，当烟囱倾角为10°，烟囱分散角为1°时，集热效率为42.54%。在透明罩倾角相同的情况下，不同的烟囱弥散角影响了SCS的烟囱进口流体速度。当色散角为2°时，速度最大可达2.090 m/s。由于SCS的透明覆盖面积大，建议将SCS与建筑和农业相结合，实现零能耗，促进农业可持续发展。

{"title":"Structural optimization of solar chimney system based on heat efficiency and flow velocity: Numerical and Experimental studies","authors":"Jing Jia , Jing Nie , Hao Su , Jin-Chen XU , Xinyao Ruan , Wei Gao","doi":"10.1016/j.csite.2024.105714","DOIUrl":"10.1016/j.csite.2024.105714","url":null,"abstract":"<div><div>This study focuses on enhancing the heat collection performance of solar chimney systems (SCS). The effect of various sizing parameters on the square SCS with a single side inlet is investigated through experimental and numerical simulations for optimization. The experimental results demonstrate significant variation in temperature uniformity among absorbers made from different materials. The composite absorber consisting of bamboo glue board, aluminum, sand, and black high-density polyethylene foam board exhibits excellent temperature uniformity. Optimization is performed with heat collection efficiency and chimney inlet fluid velocity as objective functions. The results indicate that adjusting the transparent cover inclination angle and chimney dispersion angle significantly enhances heat collection efficiency. Specifically, the SCS achieves a heat collection efficiency of 42.54 % when the inclination angle is set to 10° and the chimney dispersion angle is set to 1°. The chimney inlet fluid velocity of the SCS varies with different chimney dispersion angles at the same transparent cover inclination. At a dispersion angle of 2°, the velocity reaches a maximum of 2.090 m/s. Due to the large transparent cover area of the SCS, it is recommended to integrate the SCS with buildings and agriculture to achieve zero energy consumption and promote sustainable agriculture.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"66 ","pages":"Article 105714"},"PeriodicalIF":6.4,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142939998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The role of circular shield in improving the thermal efficiency of domestic gas stove 圆罩在提高家用燃气灶热效率中的作用

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2025-02-01 DOI: 10.1016/j.csite.2024.105730

Mingze Su , Yu Lin , Deqi Meng , Naiping Gao , Tong Zhu , Jiawei Chen , Dingrui Zhang , Zhonghua Li , Xiaowen Liu

Domestic gas stoves are widely used in the world as they are cheap and easy to use, therefore their thermal efficiency is one of the important factors affecting the great task of energy conservation and emission reduction. Installing a circular shield is the simplest and effective way to improve the thermal efficiency of domestic gas stove, but there is still no consensus on the role of installing a circular shield. In this paper, Computational fluid dynamics simulations were carried out to mimic the testing process of the thermal efficiency of domestic gas stove. Based on the simulation results, thermodynamic analysis was then conducted to determine the heat distribution in each heat transfer pathway. By means of the thermodynamic analysis, the main role of circular shield in improving the thermal efficiency of domestic gas stove was finally elucidated. The role can be expressed as: the circular shield establishes a radiation heat transfer pathway from the circular shield to the bottom wall of the pot, and through this pathway, the circular shield transfers heat absorbed from the flue gas to the bottom wall of the pot. The clarification of the above mechanism is helpful for the further optimization of circular shield.

家用燃气灶因其价格低廉、使用方便而在世界范围内得到广泛应用，因此其热效率是影响节能减排这一重大任务的重要因素之一。安装圆形护罩是提高家用燃气灶热效率最简单有效的方法，但目前对于安装圆形护罩的作用还没有达成共识。本文采用计算流体力学方法模拟了家用燃气灶热效率的测试过程。根据模拟结果，进行热力学分析，确定各传热路径的热量分布。通过热力学分析，阐明了圆形护罩对提高家用燃气灶热效率的主要作用。其作用可以表示为：圆形屏蔽板建立了一条从圆形屏蔽板到锅底壁的辐射换热通道，通过这条通道，圆形屏蔽板将烟气吸收的热量传递到锅底壁。上述机理的阐明有助于圆形屏蔽板的进一步优化。

{"title":"The role of circular shield in improving the thermal efficiency of domestic gas stove","authors":"Mingze Su , Yu Lin , Deqi Meng , Naiping Gao , Tong Zhu , Jiawei Chen , Dingrui Zhang , Zhonghua Li , Xiaowen Liu","doi":"10.1016/j.csite.2024.105730","DOIUrl":"10.1016/j.csite.2024.105730","url":null,"abstract":"<div><div>Domestic gas stoves are widely used in the world as they are cheap and easy to use, therefore their thermal efficiency is one of the important factors affecting the great task of energy conservation and emission reduction. Installing a circular shield is the simplest and effective way to improve the thermal efficiency of domestic gas stove, but there is still no consensus on the role of installing a circular shield. In this paper, Computational fluid dynamics simulations were carried out to mimic the testing process of the thermal efficiency of domestic gas stove. Based on the simulation results, thermodynamic analysis was then conducted to determine the heat distribution in each heat transfer pathway. By means of the thermodynamic analysis, the main role of circular shield in improving the thermal efficiency of domestic gas stove was finally elucidated. The role can be expressed as: the circular shield establishes a radiation heat transfer pathway from the circular shield to the bottom wall of the pot, and through this pathway, the circular shield transfers heat absorbed from the flue gas to the bottom wall of the pot. The clarification of the above mechanism is helpful for the further optimization of circular shield.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"66 ","pages":"Article 105730"},"PeriodicalIF":6.4,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142939749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Orientation effect of arc array horizontal tubes inside a phase change storage unit on melting and solidification characteristics 相变存储装置内电弧阵列水平管的取向对熔化和凝固特性的影响

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2025-02-01 DOI: 10.1016/j.csite.2025.105804

Mohamed A. Alnakeeb, Mohaned M. El-Bashouty, Mostafa M. Zaytoun, Medhat M. Sorour

This numerical study examines the phase change material melting and solidification characteristics that are filled inside the shell of different multiple-tube arc array storage units. For all studied cases, the heat transfer surface area and the PCM quantities are kept constant. The melting and solidification are numerically simulated via the enthalpy-porosity method. A two-dimensional numerical model is created using the ANSYS-FLUENT 17.2 software. The current numerical model validation is achieved by comparing it with previously published study experimental data, demonstrating a strong agreement between the present model results and the earlier experimental findings. The results show that the arc location variation significantly influences both the melt and solidification. During the melting phase, the 180° arc array orientation showed the greatest reduction in total melting time, by 80.75 %, referred to the base case. In contrast, for the solidification phase period, the orientation of the 60° arc array demonstrated the most significant reduction in total solidification time, by 7.46 %, referred to the base case. For the full cyclic process, referred to the base case, the 90° arc array orientation obtained the greatest reduction for the total full cyclic time by 16.8 %.

本文对不同多管电弧阵列存储单元壳体内填充相变材料的熔化和凝固特性进行了数值研究。对于所有研究的情况，传热表面积和PCM量保持不变。采用焓孔法对其熔化和凝固过程进行了数值模拟。利用ANSYS-FLUENT 17.2软件建立了二维数值模型。当前的数值模型验证是通过将其与先前发表的研究实验数据进行比较来实现的，表明当前模型结果与先前的实验结果之间具有很强的一致性。结果表明，电弧位置的变化对熔体和凝固均有显著影响。在熔化阶段，与基准情况相比，180°电弧阵列方向最大程度地减少了总熔化时间，减少了80.75%。相比之下，对于凝固阶段，60°电弧阵列的取向显示出最显著的总凝固时间减少，与基准情况相比，减少了7.46%。在全循环过程中，参考基准情况，90°弧阵列方向对总全循环时间的减少最大，减少了16.8%。

{"title":"Orientation effect of arc array horizontal tubes inside a phase change storage unit on melting and solidification characteristics","authors":"Mohamed A. Alnakeeb, Mohaned M. El-Bashouty, Mostafa M. Zaytoun, Medhat M. Sorour","doi":"10.1016/j.csite.2025.105804","DOIUrl":"10.1016/j.csite.2025.105804","url":null,"abstract":"<div><div>This numerical study examines the phase change material melting and solidification characteristics that are filled inside the shell of different multiple-tube arc array storage units. For all studied cases, the heat transfer surface area and the PCM quantities are kept constant. The melting and solidification are numerically simulated via the enthalpy-porosity method. A two-dimensional numerical model is created using the ANSYS-FLUENT 17.2 software. The current numerical model validation is achieved by comparing it with previously published study experimental data, demonstrating a strong agreement between the present model results and the earlier experimental findings. The results show that the arc location variation significantly influences both the melt and solidification. During the melting phase, the 180° arc array orientation showed the greatest reduction in total melting time, by 80.75 %, referred to the base case. In contrast, for the solidification phase period, the orientation of the 60° arc array demonstrated the most significant reduction in total solidification time, by 7.46 %, referred to the base case. For the full cyclic process, referred to the base case, the 90° arc array orientation obtained the greatest reduction for the total full cyclic time by 16.8 %.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"66 ","pages":"Article 105804"},"PeriodicalIF":6.4,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143021172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0