Pub Date : 2024-11-15DOI: 10.1016/j.applthermaleng.2024.124939
Zhili Sun, Wenfu Zhang, Jiao Feng, Hou Sicong, Liang Di
To solve the problem of performance reduction caused by uneven two-phase refrigerant distribution in refrigeration system, two types of distributors were applied to the experimental bench of row tube plate instant freezer with adjustable liquid supply mode. The parameters of cooling rate, refrigerating capacity, COP, and outlet superheat of the row tube plate instant freezer with the application of the two different types of distributors were analyzed. The study shows that the cooling rate of Rectifier Nozzle-Type Critical Distributor is 13.7 % faster than that of the traditional quick-freezer under the condition of downward inlet and upward outlet liquid supply mode, and the cooling rate of Liquid Storage Distributor is 10 % faster than that of the traditional quick-freezer under the condition of upward inlet and downward outlet liquid supply mode. Under the condition of evaporating temperature −31 °C ∼ -35 °C. the refrigeration capacity, COP, and superheat inhomogeneity of the Rectifier Nozzle-Type Critical Distributor system is better performance in general. Simulation is carried out in combination with experimental conditions, and The simulation results show that the formation of annular flow and critical sound velocity in the Rectifier Nozzle-Type Critical Distributor has excellent distribution ability. A new idea for solving the problem of refrigeration inefficiency is presented in this study.
{"title":"Experimental study and simulation of the rectifier nozzle-type critical distributor applied to the application of row tube plate instant freezer","authors":"Zhili Sun, Wenfu Zhang, Jiao Feng, Hou Sicong, Liang Di","doi":"10.1016/j.applthermaleng.2024.124939","DOIUrl":"10.1016/j.applthermaleng.2024.124939","url":null,"abstract":"<div><div>To solve the problem of performance reduction caused by uneven two-phase refrigerant distribution in refrigeration system, two types of distributors were applied to the experimental bench of row tube plate instant freezer with adjustable liquid supply mode. The parameters of cooling rate, refrigerating capacity, COP, and outlet superheat of the row tube plate instant freezer with the application of the two different types of distributors were analyzed. The study shows that the cooling rate of Rectifier Nozzle-Type Critical Distributor is 13.7 % faster than that of the traditional quick-freezer under the condition of downward inlet and upward outlet liquid supply mode, and the cooling rate of Liquid Storage Distributor is 10 % faster than that of the traditional quick-freezer under the condition of upward inlet and downward outlet liquid supply mode. Under the condition of evaporating temperature −31 °C ∼ -35 °C. the refrigeration capacity, COP, and superheat inhomogeneity of the Rectifier Nozzle-Type Critical Distributor system is better performance in general. Simulation is carried out in combination with experimental conditions, and The simulation results show that the formation of annular flow and critical sound velocity in the Rectifier Nozzle-Type Critical Distributor has excellent distribution ability. A new idea for solving the problem of refrigeration inefficiency is presented in this study.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"259 ","pages":"Article 124939"},"PeriodicalIF":6.1,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-15DOI: 10.1016/j.applthermaleng.2024.124914
Mohammad Azarifar , Faisal Ahmed , Mehmet Arik
This article presents an approach to the design and fabrication of synthetic jet devices (SJDs) using rapid prototyping via additive manufacturing, marking the first study to employ this method for such devices. This manufacturing technique empowers researchers with complete design freedom, enabling the production of ultra-thin SJDs—as thin as 4 mm—without mechanical fasteners and facilitating the rapid fabrication of multiple devices with varying geometries. To showcase the potential of this method, SJDs with conical and cylindrical cavities and orifices ranging from 1.6 mm to 7 mm were designed, fabricated, and tested.
These devices achieved air jet exit velocities exceeding 106 m/s using a single piezoelectric diaphragm—among the highest reported in the literature—validating the effectiveness of this manufacturing approach. This high jet velocity is significant for practical applications requiring efficient thermal management, such as cooling high-power-density electronics, where compact and energy-efficient solutions are essential. Beyond achieving high velocities, it was revealed that maximizing jet velocity alone is not always optimal for heat removal. The hydrodynamic impulse generation rate was introduced as a more significant factor influencing heat transfer performance. By fabricating and testing multiple SJDs with different geometries, it was demonstrated that the impulse generation rate, which accounts for both jet velocity and flow rate, better correlates with enhanced heat transfer capabilities than jet velocity alone. This insight addresses an often-overlooked parameter in SJD design and has substantial implications for optimizing heat removal performance. Moreover, lumped element modeling, tuned solely on diaphragm deflection behavior, accurately predicted device performance and was validated using a hotwire anemometer. This model effectively characterizes center-axis orifice devices and confirms its applicability to thin-cavity designs, providing a valuable tool for future SJD development. Despite moderate volume flow rates (0.2 to 0.8 m3/h), the fabricated SJDs delivered significant improvements in heat transfer. Compared to natural convection, these devices achieved over 13 times greater heat removal rates, with an average heat transfer coefficient exceeding 120 W/m2·K over a 30 mm × 30 mm heated surface. These findings demonstrate the practicality and effectiveness of vortex-enhanced synthetic jet impingement for targeted and efficient cooling of localized hot spots. This approach offers multiple advantages over traditional rotary cooling systems like fans, including increased reliability, lower profile, while consuming less than 100 mW. The ability to rapidly prototype and optimize SJDs using additive manufacturing accelerates research and development in this field, paving the way for advanced thermal management solutions in real-world applications.
{"title":"Vortex-enhanced jet impingement and the role of impulse generation rate in heat removal using additively manufactured synthetic jet devices","authors":"Mohammad Azarifar , Faisal Ahmed , Mehmet Arik","doi":"10.1016/j.applthermaleng.2024.124914","DOIUrl":"10.1016/j.applthermaleng.2024.124914","url":null,"abstract":"<div><div>This article presents an approach to the design and fabrication of synthetic jet devices (SJDs) using rapid prototyping via additive manufacturing, marking the first study to employ this method for such devices. This manufacturing technique empowers researchers with complete design freedom, enabling the production of ultra-thin SJDs—as thin as 4 mm—without mechanical fasteners and facilitating the rapid fabrication of multiple devices with varying geometries. To showcase the potential of this method, SJDs with conical and cylindrical cavities and orifices ranging from 1.6 mm to 7 mm were designed, fabricated, and tested.</div><div>These devices achieved air jet exit velocities exceeding 106 m/s using a single piezoelectric diaphragm—among the highest reported in the literature—validating the effectiveness of this manufacturing approach. This high jet velocity is significant for practical applications requiring efficient thermal management, such as cooling high-power-density electronics, where compact and energy-efficient solutions are essential. Beyond achieving high velocities, it was revealed that maximizing jet velocity alone is not always optimal for heat removal. The hydrodynamic impulse generation rate was introduced as a more significant factor influencing heat transfer performance. By fabricating and testing multiple SJDs with different geometries, it was demonstrated that the impulse generation rate, which accounts for both jet velocity and flow rate, better correlates with enhanced heat transfer capabilities than jet velocity alone. This insight addresses an often-overlooked parameter in SJD design and has substantial implications for optimizing heat removal performance. Moreover, lumped element modeling, tuned solely on diaphragm deflection behavior, accurately predicted device performance and was validated using a hotwire anemometer. This model effectively characterizes center-axis orifice devices and confirms its applicability to thin-cavity designs, providing a valuable tool for future SJD development. Despite moderate volume flow rates (0.2 to 0.8 m<sup>3</sup>/h), the fabricated SJDs delivered significant improvements in heat transfer. Compared to natural convection, these devices achieved over 13 times greater heat removal rates, with an average heat transfer coefficient exceeding 120 W/m<sup>2</sup>·K over a 30 mm × 30 mm heated surface. These findings demonstrate the practicality and effectiveness of vortex-enhanced synthetic jet impingement for targeted and efficient cooling of localized hot spots. This approach offers multiple advantages over traditional rotary cooling systems like fans, including increased reliability, lower profile, while consuming less than 100 mW. The ability to rapidly prototype and optimize SJDs using additive manufacturing accelerates research and development in this field, paving the way for advanced thermal management solutions in real-world applications.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"259 ","pages":"Article 124914"},"PeriodicalIF":6.1,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-14DOI: 10.1016/j.applthermaleng.2024.124933
Jihun Choi, Hyunsoo Han, Tawseef Ahmad Wani, Daewoong Kim, Sangmin Jeon
We have developed, for the first time, a rotating evaporator that synergistically performs sustainable urban cooling and electricity generation. Fabricated using 3D printing, it features a nature-inspired hierarchical water path that mimics tree transpiration. Under 1-sun illumination, the rotating evaporator achieved an evaporation rate of 2.08 kg/m2h, and in the presence of wind at a speed of 4 m/s, the evaporator began rotating, enhancing the evaporation rate to 19.58 kg/m2h. When the rotator was fixed to prevent rotation, the evaporation rate decreased by 24 %, highlighting the advantage of rotation in water evaporation by effectively preventing vapor accumulation near the evaporating surface and supplying environmental energy. Notably, the rotating evaporator provided evaporative cooling 12.2 times greater than the incident solar energy, cooling 25.6 m3 of air by 1 °C in one hour, highlighting its potential to mitigate the urban heat island effect. This rotation also generated electricity, achieving a voltage of 1.07 V and a power density of 4.73 W/m2, which was sufficient for practical applications such as lighting and water purification.
{"title":"Rotating evaporator for sustainable urban cooling and electricity generation","authors":"Jihun Choi, Hyunsoo Han, Tawseef Ahmad Wani, Daewoong Kim, Sangmin Jeon","doi":"10.1016/j.applthermaleng.2024.124933","DOIUrl":"10.1016/j.applthermaleng.2024.124933","url":null,"abstract":"<div><div>We have developed, for the first time, a rotating evaporator that synergistically performs sustainable urban cooling and electricity generation. Fabricated using 3D printing, it features a nature-inspired hierarchical water path that mimics tree transpiration. Under 1-sun illumination, the rotating evaporator achieved an evaporation rate of 2.08 kg/m<sup>2</sup>h, and in the presence of wind at a speed of 4 m/s, the evaporator began rotating, enhancing the evaporation rate to 19.58 kg/m<sup>2</sup>h. When the rotator was fixed to prevent rotation, the evaporation rate decreased by 24 %, highlighting the advantage of rotation in water evaporation by effectively preventing vapor accumulation near the evaporating surface and supplying environmental energy. Notably, the rotating evaporator provided evaporative cooling 12.2 times greater than the incident solar energy, cooling 25.6 m<sup>3</sup> of air by 1 °C in one hour, highlighting its potential to mitigate the urban heat island effect. This rotation also generated electricity, achieving a voltage of 1.07 V and a power density of 4.73 W/m<sup>2</sup>, which was sufficient for practical applications such as lighting and water purification.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"259 ","pages":"Article 124933"},"PeriodicalIF":6.1,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-14DOI: 10.1016/j.applthermaleng.2024.124930
Liangfeng Wang , Jinxin Zhang , Shufeng Huang
The accumulation of a significant amount of vapor in minichannels severely limits their flow boiling heat transfer performance, posing a challenge for efficient thermal management in high-power electronic devices. To address this issue, we propose an innovative gradient porous copper rib minichannel with a vapor separation function. This design incorporates micro-pore porous copper and open-cell porous copper, where the unique structure of the micro-pore porous copper is crucial for achieving effective vapor separation. This innovative design not only expands the vapor discharge pathways within the minichannel but also significantly enhances the overall efficiency of vapor removal. Using water as the working fluid, flow boiling experiments were conducted across a range of mass fluxes (G = 26.1 kg/(m2s) ∼ 156.9 kg/(m2s)) and heat fluxes (qeff = 38.2 kW/m2 ∼ 267.5 kW/m2). The experimental results demonstrate that vapor separation significantly alleviates backflow and enhances heat transfer performance. Specifically, our findings indicate that the average temperature of the heat transfer surface decreases by 0 to 10 °C, while the maximum heat transfer coefficient increases by 2.3 times compared to conventional designs. This work presents a practical and innovative approach to mitigating vapor accumulation in minichannels, providing valuable insights for the design of high-performance minichannel heat sinks.
{"title":"Vapor separation in minichannel heat sink flow boiling application using gradient porous copper ribs","authors":"Liangfeng Wang , Jinxin Zhang , Shufeng Huang","doi":"10.1016/j.applthermaleng.2024.124930","DOIUrl":"10.1016/j.applthermaleng.2024.124930","url":null,"abstract":"<div><div>The accumulation of a significant amount of vapor in minichannels severely limits their flow boiling heat transfer performance, posing a challenge for efficient thermal management in high-power electronic devices. To address this issue, we propose an innovative gradient porous copper rib minichannel with a vapor separation function. This design incorporates micro-pore porous copper and open-cell porous copper, where the unique structure of the micro-pore porous copper is crucial for achieving effective vapor separation. This innovative design not only expands the vapor discharge pathways within the minichannel but also significantly enhances the overall efficiency of vapor removal. Using water as the working fluid, flow boiling experiments were conducted across a range of mass fluxes (<em>G</em> = 26.1 kg/(m<sup>2</sup>s) ∼ 156.9 kg/(m<sup>2</sup>s)) and heat fluxes (<em>q<sub>eff</sub></em> = 38.2 kW/m<sup>2</sup> ∼ 267.5 kW/m<sup>2</sup>). The experimental results demonstrate that vapor separation significantly alleviates backflow and enhances heat transfer performance. Specifically, our findings indicate that the average temperature of the heat transfer surface decreases by 0 to 10 °C, while the maximum heat transfer coefficient increases by 2.3 times compared to conventional designs. This work presents a practical and innovative approach to mitigating vapor accumulation in minichannels, providing valuable insights for the design of high-performance minichannel heat sinks.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"259 ","pages":"Article 124930"},"PeriodicalIF":6.1,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-14DOI: 10.1016/j.applthermaleng.2024.124932
Jiang Huang , Jianquan Jin , Jiaxin Liang , Yuanhua He , Yonggang Chen
To investigate the suppression effect of C6F12O on the thermal runaway (TR) of NCM soft-pack lithium-ion battery (LIB) in a confined space, a combustion and suppression experimental platform was established. A 300 W heating panel was employed as an external heat source to induce TR. Results indicate that, in the absence of agents, the TR process of the fully charged NCM soft-pack battery exhibited pronounced gas release and intense jet flames, with the entire event lasting approximately 20 s. The average peak temperature on the back side of the cell (Tb-max) could be reached up to 776.5 ℃, corresponding to an average peak temperature 539.8 ℃ in surrounding environment, highlighting the potential for severe thermal hazards. The critical extinguishing dose (Xext) and the critical thermal suppression dose (Xsup) of C6F12O were determined based on its extinguishing and cooling effects. The application of C6F12O could lead to the extinguishment of battery flames within 3 s, with the Xext not less than 2.62 kg/kWh. However, low dose (0.07 kg and 0.15 kg) of C6F12O can exacerbate the temperature rise of LIBs after TR, potentially leading to re-ignition. Whereas a dosage exceeding of Xsup = 5.48 kg/kWh can exert a positive suppression effect to counteract this influence. This research provides valuable insights for selecting the optimal C6F12O dosage and designing effective firefighting measures against LIB fires, while also offering novel research directions for extinguishing strategies.
{"title":"Experimental study on fire suppression of NCM lithium-ion battery by C6F12O in a confined space","authors":"Jiang Huang , Jianquan Jin , Jiaxin Liang , Yuanhua He , Yonggang Chen","doi":"10.1016/j.applthermaleng.2024.124932","DOIUrl":"10.1016/j.applthermaleng.2024.124932","url":null,"abstract":"<div><div>To investigate the suppression effect of C<sub>6</sub>F<sub>12</sub>O on the thermal runaway (TR) of NCM soft-pack lithium-ion battery (LIB) in a confined space, a combustion and suppression experimental platform was established. A 300 W heating panel was employed as an external heat source to induce TR. Results indicate that, in the absence of agents, the TR process of the fully charged NCM soft-pack battery exhibited pronounced gas release and intense jet flames, with the entire event lasting approximately 20 s. The average peak temperature on the back side of the cell (<em>T</em><sub>b-max</sub>) could be reached up to 776.5 ℃, corresponding to an average peak temperature 539.8 ℃ in surrounding environment, highlighting the potential for severe thermal hazards. The critical extinguishing dose (<em>X</em><sub>ext</sub>) and the critical thermal suppression dose (<em>X</em><sub>sup</sub>) of C<sub>6</sub>F<sub>12</sub>O were determined based on its extinguishing and cooling effects. The application of C<sub>6</sub>F<sub>12</sub>O could lead to the extinguishment of battery flames within 3 s, with the <em>X</em><sub>ext</sub> not less than 2.62 kg/kWh. However, low dose (0.07 kg and 0.15 kg) of C<sub>6</sub>F<sub>12</sub>O can exacerbate the temperature rise of LIBs after TR, potentially leading to re-ignition. Whereas a dosage exceeding of <em>X</em><sub>sup</sub> = 5.48 kg/kWh can exert a positive suppression effect to counteract this influence. This research provides valuable insights for selecting the optimal C<sub>6</sub>F<sub>12</sub>O dosage and designing effective firefighting measures against LIB fires, while also offering novel research directions for extinguishing strategies.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"259 ","pages":"Article 124932"},"PeriodicalIF":6.1,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-14DOI: 10.1016/j.applthermaleng.2024.124928
Guang Wang , Yufeng Qiao , Sixian Liu , Jingsong Wang , Qingguo Xue
In order to utilize municipal solid waste (MSW) in blast furnace ironmaking to realize synergistic reduction of pollution and carbon emissions, a novel method for pulverization of MSW by low temperature heat treatment and crushing, and evaluation of the properties of pulverized product for blast furnace injection were performed. In the present research work, residual waste obtained from MSW classification under the conditions of most Chinese cities was used as the representative raw material. The crushing performance of MSW can be improved by heat treatment. Considering the weight loss ratio, pulverization effect and density of heated MSW at different temperatures and durations, the optimal heat treatment parameters can be set as 300 °C and 20 min. The volatile content, fixed carbon content, ash content, S content, lower heating value of the pulverized product were 61.56 wt%, 19.02 wt%, 19.42 wt%, 0.39 wt% and 25.47 kJ/g, respectively. The pulverized product had worse fluidity and similar jet flow compared to industrial injection coal. Its decomposition heat for injection was 1732 kJ/kg. The initial combustion temperature and burnout temperature of the mixed fuel gradually decreased with the increasing of added pulverized product due to its much better combustion property. About 0.163 kg CO2 can be reduced if 1 kg of raw MSW was injected into blast furnace. The experimental results demonstrates that the obtained pulverized MSW could be used for blast furnace ironmaking to some extent as an environmentally friendly, low-carbon, and economically substitute of fossil fuel.
为了在高炉炼铁中利用城市固体废弃物（MSW），实现污染和碳排放的协同减少，本研究采用了一种新型方法，通过低温热处理和破碎对城市固体废弃物进行粉碎，并对高炉喷吹用粉碎产品的性能进行了评估。在本研究工作中，采用了在中国大多数城市条件下进行 MSW 分类所获得的残余垃圾作为代表性原料。通过热处理可以改善城市生活垃圾的粉碎性能。考虑到在不同温度和持续时间下加热 MSW 的失重率、粉碎效果和密度，可将最佳热处理参数设置为 300 °C 和 20 分钟。粉碎产品的挥发物含量、固定碳含量、灰分含量、S 含量和较低的热值分别为 61.56 wt%、19.02 wt%、19.42 wt%、0.39 wt% 和 25.47 kJ/g。与工业喷吹煤相比，粉化产品的流动性更差，喷射流量相似。其喷射分解热为 1732 kJ/kg。由于煤粉的燃烧性能更好，混合燃料的初始燃烧温度和燃尽温度随着煤粉添加量的增加而逐渐降低。将 1 kg 未加工的城市固体废弃物注入高炉可减少约 0.163 kg CO2。实验结果表明，所获得的煤粉可在一定程度上用于高炉炼铁，是一种环保、低碳、经济的化石燃料替代品。
{"title":"Pulverization of municipal solid waste and utilization of pulverized product as alternative fuel for blast furnace injection","authors":"Guang Wang , Yufeng Qiao , Sixian Liu , Jingsong Wang , Qingguo Xue","doi":"10.1016/j.applthermaleng.2024.124928","DOIUrl":"10.1016/j.applthermaleng.2024.124928","url":null,"abstract":"<div><div>In order to utilize municipal solid waste (MSW) in blast furnace ironmaking to realize synergistic reduction of pollution and carbon emissions, a novel method for pulverization of MSW by low temperature heat treatment and crushing, and evaluation of the properties of pulverized product for blast furnace injection were performed. In the present research work, residual waste obtained from MSW classification under the conditions of most Chinese cities was used as the representative raw material. The crushing performance of MSW can be improved by heat treatment. Considering the weight loss ratio, pulverization effect and density of heated MSW at different temperatures and durations, the optimal heat treatment parameters can be set as 300 °C and 20 min. The volatile content, fixed carbon content, ash content, S content, lower heating value of the pulverized product were 61.56 wt%, 19.02 wt%, 19.42 wt%, 0.39 wt% and 25.47 kJ/g, respectively. The pulverized product had worse fluidity and similar jet flow compared to industrial injection coal. Its decomposition heat for injection was 1732 kJ/kg. The initial combustion temperature and burnout temperature of the mixed fuel gradually decreased with the increasing of added pulverized product due to its much better combustion property. About 0.163 kg CO<sub>2</sub> can be reduced if 1 kg of raw MSW was injected into blast furnace. The experimental results demonstrates that the obtained pulverized MSW could be used for blast furnace ironmaking to some extent as an environmentally friendly, low-carbon, and economically substitute of fossil fuel.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"259 ","pages":"Article 124928"},"PeriodicalIF":6.1,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657785","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Solar assisted air source heat pump drying (SASHPD) system has been widely studied due to its excellent energy saving and high dried quality of product. To improve system performance, the control logic of a solar assisted multi-source heat pump drying (SMSHPD) system was investigated, and the simulation model and the experimental platform were established in this paper. The seasonal operating characteristics of the air source heat pump drying (ASHPD), the SASHPD and the SMSHPD modes were studied. The energy consumption, coefficient of performance (COP) and specific moisture extraction rate (SMER) of the three drying systems were calculated and analyzed. Additionally, the water tank temperature were also measured to determine the seasonal control logic of the drying system. It was found that compared to the ASHPD system, in summer, the energy consumption of the SASHPD system was reduced by 33.06 %, and COP and SMER was increased by 49.4 % and 49.38 %, respectively. Moreover, because of the high ambient temperature and water tank temperature, the experimental results indicated that only the SASHPD control logic should be implemented in summer. The maximum error of the simulation results was 9.1 % and the accuracy of the simulation model was confirmed. In autumn, the lower water tank temperature after drying illustrated that the solar energy can be more fully utilized, which explained why the performance of the SMSHPD mode was increased by 6.5 % compared to the SASHPD mode. Consequently, it is necessary to implement the SMSHPD control logic in autumn. Moreover, the operating temperature of the water source heat pump drying mode in autumn was optimized and the optimal temperature range was 28–54 °C. The average COP in one week after optimization was 6.21 % higher than that of the original operating temperature. Based on the validated simulation model, the optimal operating temperatures in spring and winter were also calculated and the control logic of the SMSHPD system operating in the four seasons were all obtained. This paper has important guiding significance for the reasonable choice of the control logic of a solar combined air source heat pump drying system.
{"title":"Study and optimization of the influence of the water tank temperature on the performance of a solar assisted multi-source heat pump drying system","authors":"Feng Hou, Yan Lu, Ting He, Hongchuang Sun, Yawei Li, Pei Yuan","doi":"10.1016/j.applthermaleng.2024.124922","DOIUrl":"10.1016/j.applthermaleng.2024.124922","url":null,"abstract":"<div><div>Solar assisted air source heat pump drying (SASHPD) system has been widely studied due to its excellent energy saving and high dried quality of product. To improve system performance, the control logic of a solar assisted multi-source heat pump drying (SMSHPD) system was investigated, and the simulation model and the experimental platform were established in this paper. The seasonal operating characteristics of the air source heat pump drying (ASHPD), the SASHPD and the SMSHPD modes were studied. The energy consumption, coefficient of performance (COP) and specific moisture extraction rate (SMER) of the three drying systems were calculated and analyzed. Additionally, the water tank temperature were also measured to determine the seasonal control logic of the drying system. It was found that compared to the ASHPD system, in summer, the energy consumption of the SASHPD system was reduced by 33.06 %, and COP and SMER was increased by 49.4 % and 49.38 %, respectively. Moreover, because of the high ambient temperature and water tank temperature, the experimental results indicated that only the SASHPD control logic should be implemented in summer. The maximum error of the simulation results was 9.1 % and the accuracy of the simulation model was confirmed. In autumn, the lower water tank temperature after drying illustrated that the solar energy can be more fully utilized, which explained why the performance of the SMSHPD mode was increased by 6.5 % compared to the SASHPD mode. Consequently, it is necessary to implement the SMSHPD control logic in autumn. Moreover, the operating temperature of the water source heat pump drying mode in autumn was optimized and the optimal temperature range was 28–54 °C. The average COP in one week after optimization was 6.21 % higher than that of the original operating temperature. Based on the validated simulation model, the optimal operating temperatures in spring and winter were also calculated and the control logic of the SMSHPD system operating in the four seasons were all obtained. This paper has important guiding significance for the reasonable choice of the control logic of a solar combined air source heat pump drying system.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"259 ","pages":"Article 124922"},"PeriodicalIF":6.1,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142658196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Metal foams with excellent mechanical properties and low effective thermal conductivity (ETC) are widely used in high-temperature components. The 3D microstructure evolution under high-temperature loading is complex. The deformation mode and ETC at high temperature of metal foams are determined by the microstructure at different stress and the parent material properties. In this paper, high-temperature in-situ micro X-ray computed tomography (μ-CT) compressive test was performed to monitor the 3D microstructure evolution and failure mechanism of closed-cell Al foams at 300 ℃. High-fidelity material twin models were then generated from the in-situ μ-CT scans under various high-temperature loadings to calculate the corresponding ETC of the foams. The effects of the applied strain and corresponding 3D microstructure on the ETC were discussed based on experimental and simulation results. The results reveal that the 3D porosity and ETC evolution of foam compressed at 300 °C are bilinear. A compressive strain of 30 % was identified as a critical strain, beyond which both porosity and ETC change dramatically with increasing strain. Finally, a theoretical model based on the Kelvin tetrakaidecahedron was developed to reveal the effect of microstructure evolution caused by compressive strain on the ETC of foams.
{"title":"High temperature in-situ 3D monitor of microstructure evolution and heat transfer performance of metal foam","authors":"Sihang Xiao, Tianhua Wen, Zhaoliang Qu, Shengyu Duan, Panding Wang, Hongshuai Lei, Daining Fang","doi":"10.1016/j.applthermaleng.2024.124864","DOIUrl":"10.1016/j.applthermaleng.2024.124864","url":null,"abstract":"<div><div>Metal foams with excellent mechanical properties and low effective thermal conductivity (ETC) are widely used in high-temperature components. The 3D microstructure evolution under high-temperature loading is complex. The deformation mode and ETC at high temperature of metal foams are determined by the microstructure at different stress and the parent material properties. In this paper, high-temperature <em>in-situ</em> micro X-ray computed tomography (μ-CT) compressive test was performed to monitor the 3D microstructure evolution and failure mechanism of closed-cell Al foams at 300 ℃. High-fidelity material twin models were then generated from the <em>in-situ</em> μ-CT scans under various high-temperature loadings to calculate the corresponding ETC of the foams. The effects of the applied strain and corresponding 3D microstructure on the ETC were discussed based on experimental and simulation results. The results reveal that the 3D porosity and ETC evolution of foam compressed at 300 °C are bilinear. A compressive strain of 30 % was identified as a critical strain, beyond which both porosity and ETC change dramatically with increasing strain. Finally, a theoretical model based on the Kelvin tetrakaidecahedron was developed to reveal the effect of microstructure evolution caused by compressive strain on the ETC of foams.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"259 ","pages":"Article 124864"},"PeriodicalIF":6.1,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-14DOI: 10.1016/j.applthermaleng.2024.124929
Xiangbo Huang , Weiyu Tang , Zan Wu , Yifan Wang , Li Luo , Kuang Sheng
Two-phase manifold microchannel heat sinks have gained significant interest for their efficient use of the coolant’s latent heat. Despite this, manifold microchannel flow boiling heat transfer has not yet been applied to wide-bandgap semiconductor power modules with multiple chips, primarily due to the complexity of the process and challenges related to electrical insulation. This study introduces a novel embedded manifold microchannel design that ensures uniform mass flow distribution, tailored for the thermal management of multi-chip power modules. The microchannels were laser-etched onto direct bonded copper (DBC) to reduce thermal resistance while maintaining electrical insulation. Thermal test vehicles (TTVs) for multi-chip power modules, featuring two different microchannel widths, were assembled using silver sintering. Experimental tests were then conducted using HFE-7100 as the coolant to evaluate two-phase heat dissipation performance. Results indicate that during flow boiling heat transfer, the temperature difference between chips in a power module strongly correlates with the exit quality. A higher coolant mass flow rate significantly reduces temperature variation between chips, particularly under high chip heat flux. At a coolant mass flow rate of 9 g/s, with a chip heat flux of 357 W/cm2 and total heat dissipation of 536 W, the minimum thermal resistance reached 0.15 cm2∙K/W, yielding a COP of 1391. With a slight sacrifice in thermal resistance, 0.17 cm2∙K/W and 0.20 cm2∙K/W were achieved at mass flow rates of 6 g/s and 3 g/s, respectively. Correspondingly, the COPs reached 2179 and 6749. This research offers valuable insights for applying flow boiling heat transfer with dielectric coolants to cool multi-chip power modules.
{"title":"Flow boiling of HFE-7100 for cooling Multi-Chip modules using manifold microchannels","authors":"Xiangbo Huang , Weiyu Tang , Zan Wu , Yifan Wang , Li Luo , Kuang Sheng","doi":"10.1016/j.applthermaleng.2024.124929","DOIUrl":"10.1016/j.applthermaleng.2024.124929","url":null,"abstract":"<div><div>Two-phase manifold microchannel heat sinks have gained significant interest for their efficient use of the coolant’s latent heat. Despite this, manifold microchannel flow boiling heat transfer has not yet been applied to wide-bandgap semiconductor power modules with multiple chips, primarily due to the complexity of the process and challenges related to electrical insulation. This study introduces a novel embedded manifold microchannel design that ensures uniform mass flow distribution, tailored for the thermal management of multi-chip power modules. The microchannels were laser-etched onto direct bonded copper (DBC) to reduce thermal resistance while maintaining electrical insulation. Thermal test vehicles (TTVs) for multi-chip power modules, featuring two different microchannel widths, were assembled using silver sintering. Experimental tests were then conducted using HFE-7100 as the coolant to evaluate two-phase heat dissipation performance. Results indicate that during flow boiling heat transfer, the temperature difference between chips in a power module strongly correlates with the exit quality. A higher coolant mass flow rate significantly reduces temperature variation between chips, particularly under high chip heat flux. At a coolant mass flow rate of 9 g/s, with a chip heat flux of 357 W/cm<sup>2</sup> and total heat dissipation of 536 W, the minimum thermal resistance reached 0.15 cm<sup>2</sup>∙K/W, yielding a COP of 1391. With a slight sacrifice in thermal resistance, 0.17 cm<sup>2</sup>∙K/W and 0.20 cm<sup>2</sup>∙K/W were achieved at mass flow rates of 6 g/s and 3 g/s, respectively. Correspondingly, the COPs reached 2179 and 6749. This research offers valuable insights for applying flow boiling heat transfer with dielectric coolants to cool multi-chip power modules.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"259 ","pages":"Article 124929"},"PeriodicalIF":6.1,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-13DOI: 10.1016/j.applthermaleng.2024.124926
Sasan Mozafari, Hossein Ali Pakravan, Reza Kamali
Microencapsulated phase change material slurry (MPCS) is a novel cooling fluid with promising performance. This study numerically investigates heat transfer and flow characteristics of MPCS within wavy microchannels. MPCS is modeled as a homogeneous, Newtonian fluid. Five wavy geometries were examined across a Reynolds number range of 50 to 250 (laminar flow regime), varying in amplitude and wavelength. The model results show that with increase in Reynolds number and decrease in the amplitude and radius of curvature of wavy microchannels, the pressure drop and Nusselt number also increase. Furthermore, the results reveal that Dean vortices intensify with increasing wave amplitude and Reynolds number. Conversely, these vortices weaken as channel wavelength and radius of curvature increase. The formation of Dean vortices enhances fluid mixing and consequently improves the thermal performance of the slurry. The study concludes that in wavy microchannels employing MPCS, increasing the Reynolds number, increasing the channel amplitude with respect to wavelength, and decreasing the radius of curvature improves the overall performance. Also, the results reveal that in higher Reynolds numbers, the radius of curvature is the most effective parameter on the overall performance of wavy microchannels.
{"title":"Thermal and hydrodynamic characteristics of microencapsulated phase change materials slurry flow in wavy microchannels","authors":"Sasan Mozafari, Hossein Ali Pakravan, Reza Kamali","doi":"10.1016/j.applthermaleng.2024.124926","DOIUrl":"10.1016/j.applthermaleng.2024.124926","url":null,"abstract":"<div><div>Microencapsulated phase change material slurry (MPCS) is a novel cooling fluid with promising performance. This study numerically investigates heat transfer and flow characteristics of MPCS within wavy microchannels. MPCS is modeled as a homogeneous, Newtonian fluid. Five wavy geometries were examined across a Reynolds number range of 50 to 250 (laminar flow regime), varying in amplitude and wavelength. The model results show that with increase in Reynolds number and decrease in the amplitude and radius of curvature of wavy microchannels, the pressure drop and Nusselt number also increase. Furthermore, the results reveal that Dean vortices intensify with increasing wave amplitude and Reynolds number. Conversely, these vortices weaken as channel wavelength and radius of curvature increase. The formation of Dean vortices enhances fluid mixing and consequently improves the thermal performance of the slurry. The study concludes that in wavy microchannels employing MPCS, increasing the Reynolds number, increasing the channel amplitude with respect to wavelength, and decreasing the radius of curvature improves the overall performance. Also, the results reveal that in higher Reynolds numbers, the radius of curvature is the most effective parameter on the overall performance of wavy microchannels.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"259 ","pages":"Article 124926"},"PeriodicalIF":6.1,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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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