International Communications in Heat and Mass Transfer最新文献

英文中文

Numerical investigation on vacuum spray flash evaporation of ethanol-water solution

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2025-02-20 DOI: 10.1016/j.icheatmasstransfer.2025.108719

Benan Cai , Jianxin Zhang , Yuqi Zhao , Xunjian Che , Jianchuang Sun , Jiameng Tian , Weihua Cai

To investigate the flash evaporation of aqueous ethanol in vacuum environment, a correction factor is introduced to modify the flash evaporation rate equation. The modified method is based on the Lagrangian-Eulerian model that couples the momentum and mass transfer of continuous and discrete phases. The results for droplets temperature exhibit average errors of less than 3.28 K compared to experimental data, thereby verifying accuracy of the method. Through the analysis of the flash evaporation behavior of two-component droplets, two distinct stages can be identified. “The first stage of flashing” is characterized by high flash evaporation rate, rapid temperature decline, and short duration, while “the second stage of flashing” is opposite to the Stage I. As the droplet size increases and the initial ethanol concentration decreases, it is observed that the duration of Stage I increases. This phenomenon extends the duration of high flash evaporation rate, thereby enhancing the mass transfer to the vapor, leads to larger decline of ethanol mass fraction. Increasing the spray temperature or decreasing the vacuum pressure can also enhance the mass transfer and flash evaporation rate. However, spray temperature shows a more significant effect on the flash evaporation rate and evaporated mass than that of vacuum pressure.

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引用次数: 0

Heat transfer performance and bubble-particle interaction dynamics in particle-laden pool boiling

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2025-02-20 DOI: 10.1016/j.icheatmasstransfer.2025.108735

Xin Chen, Ying Zhang, Hekun Jia, Bifeng Yin, Jie Ni, Li Xin, Fei Dong

Adding particles to fluids to enhance boiling heat transfer is promising, with particle size critically influencing boiling behavior. This study experimentally investigates boiling heat transfer and bubble-particle dynamics in particle-laden fluids, emphasizing the effects of aluminum particle size. Boiling curves were recorded, and the dynamics of particle-bubble interactions were captured. Particle and gas-liquid flow patterns were categorized, and the impact of particle-bubble interactions on heat transfer was analyzed. The results indicate that when superheat (ΔT) < 14 K, boiling performance relates positively to particle size. When ΔT exceeds 14 K, it's negative. At low superheat, particles deposit on the heated surface, promoting bubble nucleation and growth in corners. Larger particles provide a greater contact area, promoting bubble growth. Bubbles preferentially detach from the gaps between particles, and larger sizes facilitate this process. As the superheat increases, bubbles begin to merge, forming columns or vapor mass. Smaller particles (1–2 mm) adhere to bubbles, ascending with them in a fluidized state, while larger particles (3–4 mm) resist bubble displacement, leading to bubble/vapor film accumulation on the heated surface, particle suspension, and heat transfer deterioration. Particle bouncing enhances bubble nucleate and growth. Simulation shows particle settling affects local pressure to promotes this process.

{"title":"Heat transfer performance and bubble-particle interaction dynamics in particle-laden pool boiling","authors":"Xin Chen, Ying Zhang, Hekun Jia, Bifeng Yin, Jie Ni, Li Xin, Fei Dong","doi":"10.1016/j.icheatmasstransfer.2025.108735","DOIUrl":"10.1016/j.icheatmasstransfer.2025.108735","url":null,"abstract":"<div><div>Adding particles to fluids to enhance boiling heat transfer is promising, with particle size critically influencing boiling behavior. This study experimentally investigates boiling heat transfer and bubble-particle dynamics in particle-laden fluids, emphasizing the effects of aluminum particle size. Boiling curves were recorded, and the dynamics of particle-bubble interactions were captured. Particle and gas-liquid flow patterns were categorized, and the impact of particle-bubble interactions on heat transfer was analyzed. The results indicate that when superheat (ΔT) < 14 K, boiling performance relates positively to particle size. When ΔT exceeds 14 K, it's negative. At low superheat, particles deposit on the heated surface, promoting bubble nucleation and growth in corners. Larger particles provide a greater contact area, promoting bubble growth. Bubbles preferentially detach from the gaps between particles, and larger sizes facilitate this process. As the superheat increases, bubbles begin to merge, forming columns or vapor mass. Smaller particles (1–2 mm) adhere to bubbles, ascending with them in a fluidized state, while larger particles (3–4 mm) resist bubble displacement, leading to bubble/vapor film accumulation on the heated surface, particle suspension, and heat transfer deterioration. Particle bouncing enhances bubble nucleate and growth. Simulation shows particle settling affects local pressure to promotes this process.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"163 ","pages":"Article 108735"},"PeriodicalIF":6.4,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143454388","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}

引用次数: 0

Integrating perimeter constraints into topology optimization of thermal conduction structures considering the manufacturing efficiency

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2025-02-20 DOI: 10.1016/j.icheatmasstransfer.2025.108736

Bing Yi , Jiawei Liu , Rui Liu , Xiang Peng

Topology optimization has the advantages of large design freedom and optimization searching space. Hence, it has been introduced into the topology optimization of structures with excellent thermal conductive properties with given volume constraints. However, the optimized structures contain a lot of complex geometry, which increases the difficulty and cost of manufacturing. To address these challenges by balancing the manufacturing cost and thermal conductivity property, a perimeter-constrained topology optimization method for thermal conduction structures is proposed. First, the structural boundaries are extracted by using the modified two-step filter and projection process, which directly relates to the manufacturing costs. Subsequently, the perimeter constraint is integrated into the formulation of the topology optimization model based on Solid Isotropic Material with Penalization (SIMP), and the thermal compliance is set as the objective function. Then, the sensitivity analysis is derived for both the constraints and objective function, and the method of moving asymptotes (MMA) is used to solve the model iteratively. Finally, several numerical examples are conducted to show the performance of the proposed method for topology optimization of heat conduction structure under various boundary conditions. The average temperature of the examples only improved by 2–3 K under the condition that the perimeter is reduced by 50 % of the conventional results. The results validate the effectiveness of the proposed method for the ability to balance the manufacturing costs and the thermal conductivity property of the optimized structure according to the requirements of the designers.

{"title":"Integrating perimeter constraints into topology optimization of thermal conduction structures considering the manufacturing efficiency","authors":"Bing Yi , Jiawei Liu , Rui Liu , Xiang Peng","doi":"10.1016/j.icheatmasstransfer.2025.108736","DOIUrl":"10.1016/j.icheatmasstransfer.2025.108736","url":null,"abstract":"<div><div>Topology optimization has the advantages of large design freedom and optimization searching space. Hence, it has been introduced into the topology optimization of structures with excellent thermal conductive properties with given volume constraints. However, the optimized structures contain a lot of complex geometry, which increases the difficulty and cost of manufacturing. To address these challenges by balancing the manufacturing cost and thermal conductivity property, a perimeter-constrained topology optimization method for thermal conduction structures is proposed. First, the structural boundaries are extracted by using the modified two-step filter and projection process, which directly relates to the manufacturing costs. Subsequently, the perimeter constraint is integrated into the formulation of the topology optimization model based on Solid Isotropic Material with Penalization (SIMP), and the thermal compliance is set as the objective function. Then, the sensitivity analysis is derived for both the constraints and objective function, and the method of moving asymptotes (MMA) is used to solve the model iteratively. Finally, several numerical examples are conducted to show the performance of the proposed method for topology optimization of heat conduction structure under various boundary conditions. The average temperature of the examples only improved by 2–3 K under the condition that the perimeter is reduced by 50 % of the conventional results. The results validate the effectiveness of the proposed method for the ability to balance the manufacturing costs and the thermal conductivity property of the optimized structure according to the requirements of the designers.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"163 ","pages":"Article 108736"},"PeriodicalIF":6.4,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143444714","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}

引用次数: 0

Dynamic evolution behaviors and heat feedback characteristics in the co-burning of a large-area dike fire and multiple tank fires

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2025-02-20 DOI: 10.1016/j.icheatmasstransfer.2025.108717

Qineng Zhou , Fanliang Ge , Jie Ji , Chen Wang

The co-burning of multiple tank fires and dike fire is a typical fire phenomenon in massive fire accidents, which involved intricate heat and mass transfer processes. This study aims to investigate the dynamic evolution behaviors and explore the heat feedback characteristics exhibited by co-burning fires. A series of co-burning fires (CBFs) experiments with different tank spacings were conducted. For comparison, the experiments of double tank fires (DTFs) and dike fire (DF) were also conducted. The flame morphology of CBFs shows that the burning process can be divided into four stages, i.e., elevated and ground fire of initial stage, boiling over stage, quasi-stable co-burning stage, and extinguishing stage. During the quasi-stable stage, the fuel of the tank is in film boiling. And the mass loss rate of the tank increases sharply accompanied by flame lift-off compared with discrete double tank fires. It indicates that the heat feedback enhancement plays a dominant role due to the direct heating of sidewall by the dike fire. The analysis of heat feedback reveals that the mode of heat conduction changes and the dominated heat feedback for CBFs has shifted from radiation to conduction compared with DTFs, accounting for about 65 % of the total heat feedback.

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引用次数: 0

Numerical analysis of crystallization and freezing of flying droplet in artificial snowmaking

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2025-02-20 DOI: 10.1016/j.icheatmasstransfer.2025.108740

Peiwen Dong, Yinlong Li, Guoqiang Liu, Gang Yan

Artificial snowmaking is a kind of spray freezing, including heat and mass transfer and crystallization. The freezing process of flying droplets is complex, involving various transient characteristics. In this paper, the aim is to explore the transient characteristics of flying droplet freezing process during artificial snowmaking. A numerical model of flying droplet freezing is established combining with heat transfer theory and crystallization kinetics after experimental validation. The model incorporates the compressible flow, gas throttling, air entrainment and droplet trajectory to reveal the transient properties of flying droplet. The influence of ambient and operating parameters on the freezing time is comprehensively studied, such as the initial droplet temperature, diameter and velocity, the ambient temperature, humidity and pressure and the Mach number of airflow from nozzle. It is found that the influence of ambient temperature, droplet diameter, and Mach number is more significant on droplet freezing. When the ambient temperature is −5 °C and the Mach number is 3, the lowest temperature of 50 μm droplets can reach −7.13 °C. Finally, a critical criterion for snowmaking is proposed, which provides a new approach to compensate for the insufficient ambient temperature by adjusting the initial droplet diameter and Mach number.

{"title":"Numerical analysis of crystallization and freezing of flying droplet in artificial snowmaking","authors":"Peiwen Dong, Yinlong Li, Guoqiang Liu, Gang Yan","doi":"10.1016/j.icheatmasstransfer.2025.108740","DOIUrl":"10.1016/j.icheatmasstransfer.2025.108740","url":null,"abstract":"<div><div>Artificial snowmaking is a kind of spray freezing, including heat and mass transfer and crystallization. The freezing process of flying droplets is complex, involving various transient characteristics. In this paper, the aim is to explore the transient characteristics of flying droplet freezing process during artificial snowmaking. A numerical model of flying droplet freezing is established combining with heat transfer theory and crystallization kinetics after experimental validation. The model incorporates the compressible flow, gas throttling, air entrainment and droplet trajectory to reveal the transient properties of flying droplet. The influence of ambient and operating parameters on the freezing time is comprehensively studied, such as the initial droplet temperature, diameter and velocity, the ambient temperature, humidity and pressure and the Mach number of airflow from nozzle. It is found that the influence of ambient temperature, droplet diameter, and Mach number is more significant on droplet freezing. When the ambient temperature is <em>−</em>5 °C and the Mach number is 3, the lowest temperature of 50 μm droplets can reach <em>−</em>7.13 °C. Finally, a critical criterion for snowmaking is proposed, which provides a new approach to compensate for the insufficient ambient temperature by adjusting the initial droplet diameter and Mach number.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"163 ","pages":"Article 108740"},"PeriodicalIF":6.4,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143454446","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}

引用次数: 0

Modeling and analysis of supercritical hydrocarbon fuel heat and mass transfer with catalytic steam reforming

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2025-02-20 DOI: 10.1016/j.icheatmasstransfer.2025.108703

Shuai Xu , Junbo He , Yu Feng , Fuqiang Chen , Jiang Qin

Regenerative cooling technology is crucial for addressing the severe thermal protection challenges faced by engines in hypersonic vehicles. The steam reforming reaction of hydrocarbon fuels is an effective method for significantly enhancing the fuel's heat absorption capacity. Current research has not fully examined the correlation of convective heat transfer coefficients and their relationship with the endothermic capacity of steam reforming reactions. In this study, the catalyst coating is simplified as a surface with no thickness, and a multidimensional numerical simulation model for the steam reforming reaction of n-decane at supercritical pressure is proposed, applicable under constant wall heat flux. The model has been validated against experimental results, showing a maximum relative error in fuel conversion of 12 %. Gnielinski correlation is tested to be applicable for convective heat transfer predictions in range of 7000 ≤ Re ≤ 180,000, and fuel conversion less than 20 %. An augmentation ratio, defined as the ratio of total to physical heat sink increase per unit tube length, is introduced. Using this ratio, the predicted total heat transfer coefficient shows a deviation of no more than 16 %.

再生冷却技术对于解决高超音速飞行器发动机所面临的严峻热保护挑战至关重要。碳氢化合物燃料的蒸汽重整反应是显著提高燃料吸热能力的有效方法。目前的研究尚未充分研究对流传热系数及其与蒸汽转化反应内热能力的关系。本研究将催化剂涂层简化为无厚度的表面，并提出了适用于正癸烷在超临界压力下蒸汽转化反应的多维数值模拟模型，该模型适用于恒定壁面热通量条件下。该模型与实验结果进行了验证，结果显示燃料转化率的最大相对误差为 12%。经测试，Gnielinski 相关性适用于 7000 ≤ Re ≤ 180,000 范围内的对流传热预测，燃料转化率小于 20%。引入了一个增量比，定义为单位管长的总散热量与物理散热量之比。使用该比率，预测的总传热系数偏差不超过 16%。

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引用次数: 0

A supercritical carbon dioxide cooling heat transfer machine learning prediction model based on direct numerical simulation

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2025-02-20 DOI: 10.1016/j.icheatmasstransfer.2025.108753

Dingchen Wu , Mingshan Wei , Ran Tian , Yihang Zhao , Jianshe Guo

The severe thermo-physical properties variations of supercritical fluids in the vicinity of the critical point lead to difficulty in heat transfer prediction. In this paper, a novel prediction model for supercritical CO₂ (sCO₂) cooling heat transfer is proposed, integrating a Direct Numerical Simulation (DNS) database with the CatBoost algorithm. A high-precision heat transfer prediction database was established based on DNS data (8192 data points in total). The feature parameters were screened utilizing the random forest feature importance method. More importantly, a newly dimensionless parameter,

{Re}^{- 0.9} π_{A}

, was selected as one of the feature parameters.

{Re}^{- 0.9} π_{A}

represents the impact of near-wall acceleration caused by buoyancy, and it demonstrated the highest feature importance during training and screening processes. Based on the selected ten characteristic parameters, a robust data-driven heat transfer prediction model for sCO₂ was developed. The CatBoost algorithm outperformed the other three widely used machine learning algorithm s across training sets, testing sets, and actual predictions, achieving a mean absolute percentage error reduction of up to 22.69 %. Through comparison with 6 traditional heat transfer correlations, the results showed that the CatBoost-based sCO2 cooling heat transfer prediction model exhibits superior training speed and predictive accuracy, with a maximum relative error of merely 6.57 %. Moreover, when validated through experimental data with large Reynolds number, this model still has the highest accuracy, with 91.3 % of the data sets having a prediction accuracy within ±30 % for the Nusselt number.

{"title":"A supercritical carbon dioxide cooling heat transfer machine learning prediction model based on direct numerical simulation","authors":"Dingchen Wu , Mingshan Wei , Ran Tian , Yihang Zhao , Jianshe Guo","doi":"10.1016/j.icheatmasstransfer.2025.108753","DOIUrl":"10.1016/j.icheatmasstransfer.2025.108753","url":null,"abstract":"<div><div>The severe thermo-physical properties variations of supercritical fluids in the vicinity of the critical point lead to difficulty in heat transfer prediction. In this paper, a novel prediction model for supercritical CO<sub>2</sub> (sCO<sub>2</sub>) cooling heat transfer is proposed, integrating a Direct Numerical Simulation (DNS) database with the CatBoost algorithm. A high-precision heat transfer prediction database was established based on DNS data (8192 data points in total). The feature parameters were screened utilizing the random forest feature importance method. More importantly, a newly dimensionless parameter, <span><math><msup><mo>Re</mo><mrow><mo>−</mo><mn>0.9</mn></mrow></msup><msub><mi>π</mi><mi>A</mi></msub></math></span>, was selected as one of the feature parameters. <span><math><msup><mo>Re</mo><mrow><mo>−</mo><mn>0.9</mn></mrow></msup><msub><mi>π</mi><mi>A</mi></msub></math></span> represents the impact of near-wall acceleration caused by buoyancy, and it demonstrated the highest feature importance during training and screening processes. Based on the selected ten characteristic parameters, a robust data-driven heat transfer prediction model for sCO<sub>2</sub> was developed. The CatBoost algorithm outperformed the other three widely used machine learning algorithm s across training sets, testing sets, and actual predictions, achieving a mean absolute percentage error reduction of up to 22.69 %. Through comparison with 6 traditional heat transfer correlations, the results showed that the CatBoost-based sCO2 cooling heat transfer prediction model exhibits superior training speed and predictive accuracy, with a maximum relative error of merely 6.57 %. Moreover, when validated through experimental data with large Reynolds number, this model still has the highest accuracy, with 91.3 % of the data sets having a prediction accuracy within ±30 % for the Nusselt number.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"163 ","pages":"Article 108753"},"PeriodicalIF":6.4,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143454484","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}

引用次数: 0

Technical note: Extension of full-spectrum correlated k-distribution look-up tables to CH4 and NH3 for use in combustion modelling

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2025-02-19 DOI: 10.1016/j.icheatmasstransfer.2025.108752

Xin Wang , Zheqi Xu , Hongyuan Di , Chaojun Wang

Due to reliable accuracy and computational efficiency, full-spectrum correlated k-distribution (FSCK) look-up tables (short for traditional FSCK tables) have continuously gained popularities; however, they are only valid for combustion products and intermediates, such as CO₂, H₂O, CO and soot. Gas fuels, i.e., CH₄, NH₃ or their mixture, also display complex spectral or ‘nongray’ behaviors across spectrum. While those gas fuels are commonly consumed during combustion, their spectral behaviors may affect ignition, flame spread and chemical reactions. Therefore, it is necessary to include spectral properties of both CH₄ and NH₃ into FSCK look-up tables. To achieve this, a separate FSCK look-up tables (short for extended FSCK tables) including only CH₄ and NH₃ is constructed in this work. The multiplicative mixing scheme is then used to mix k-distributions from traditional FSCK tables and those from extended FSCK tables. A realistic non-premixed flame is used to validate both efficiency and accuracy of extended FSCK tables as well as multiplicative mixing scheme. Results show that absorption from CH₄ and NH₃ during combustion is strong and cannot be ignored. Results also show that treating spectral properties of CH₄ and NH₃ to be gray may bring in significant errors.

{"title":"Technical note: Extension of full-spectrum correlated k-distribution look-up tables to CH4 and NH3 for use in combustion modelling","authors":"Xin Wang , Zheqi Xu , Hongyuan Di , Chaojun Wang","doi":"10.1016/j.icheatmasstransfer.2025.108752","DOIUrl":"10.1016/j.icheatmasstransfer.2025.108752","url":null,"abstract":"<div><div>Due to reliable accuracy and computational efficiency, full-spectrum correlated <em>k</em>-distribution (FSCK) look-up tables (short for traditional FSCK tables) have continuously gained popularities; however, they are only valid for combustion products and intermediates, such as CO<sub>2</sub>, H<sub>2</sub>O, CO and soot. Gas fuels, i.e., CH<sub>4</sub>, NH<sub>3</sub> or their mixture, also display complex spectral or ‘nongray’ behaviors across spectrum. While those gas fuels are commonly consumed during combustion, their spectral behaviors may affect ignition, flame spread and chemical reactions. Therefore, it is necessary to include spectral properties of both CH<sub>4</sub> and NH<sub>3</sub> into FSCK look-up tables. To achieve this, a separate FSCK look-up tables (short for extended FSCK tables) including only CH<sub>4</sub> and NH<sub>3</sub> is constructed in this work. The multiplicative mixing scheme is then used to mix <em>k</em>-distributions from traditional FSCK tables and those from extended FSCK tables. A realistic non-premixed flame is used to validate both efficiency and accuracy of extended FSCK tables as well as multiplicative mixing scheme. Results show that absorption from CH<sub>4</sub> and NH<sub>3</sub> during combustion is strong and cannot be ignored. Results also show that treating spectral properties of CH<sub>4</sub> and NH<sub>3</sub> to be gray may bring in significant errors.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"163 ","pages":"Article 108752"},"PeriodicalIF":6.4,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437011","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}

引用次数: 0

Temperature dependent viscosity effect and conductivity on the sphere rotating surface

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2025-02-19 DOI: 10.1016/j.icheatmasstransfer.2025.108657

Mair Khan , T. Salahuddin , Sadia Ayub , Basem Al Awan , Meznah M. Alanazi , M. Afzal

Consider a steady flow analysis with temperature dependent viscosity and variable thermal conductivity near a rotating sphere. Additionally, a temperature dependent viscosity and variable thermal conductivity has been assumed for the current analysis. Partial differential equation system is converted into a differential system for distinct regions near the boundary layer region. Power series is used to calculate the solution of the problem. Ordinary differential systems are obtained by using this mythology. The sensitivity parameter shows reducing impact as it is showed for rotating disk problem. Temperature dependent liquid viscosity is analyzed to decrease the base flow profile the range, but for gases opposite impact is noticed. Variable thermal conductivity increase the temperature profile. The comparative results is evaluated for a limited case and good agreement is shown with previously published work.

引用次数: 0

Enhancement of the solar water heater thermodynamic performance by utilizing solar panels under diverse scenarios: Comprehensive outlook

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2025-02-19 DOI: 10.1016/j.icheatmasstransfer.2025.108734

Mehdi Ahmadi Jirdehi , Mohammad Shaterabadi , Atif Iqbal

This study examines the impact of PV output power on SWH performance by utilizing GAMS and TSOL software specialized tools for simulating solar thermal systems and optimizing the integrated system's performance under real-world conditions. The research considers various scenarios. A baseline scenario established performance benchmarks, while reflector integration improved efficiency by increasing solar radiation on the collector. Seasonal variation scenarios modeled performance across summer and winter, leveraging auxiliary systems during colder months. Cost-priority scenarios minimized expenses with trade-offs in energy output, whereas pollution-priority scenarios emphasized emissions reduction by prioritizing renewable energy sources. TSOL's flexibility provided robust and adaptable insights for these evaluations. The system incorporates a thermal element to supplement energy on cloudy days, with solar panels as the primary energy source. A key advantage of the proposed methods is their ability to generate thermal energy at night. The performance is assessed based on shading, the number of SWH tubes, and reflection using actual weather data from Kermanshah, Iran. By adopting a comprehensive approach that considers both microscopic and macroscopic factors, the system improves occupant comfort while reducing electricity demand on the main grid. The findings demonstrate the effectiveness of the proposed planning and validate this innovative approach.

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引用次数: 0

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