International Journal of Heat and Mass Transfer最新文献

{"title":"Study on oil cooling method for the powertrain of electric vehicles","authors":"Youngkyo Kim ,&nbsp;Tae Young Beom ,&nbsp;Tae Wook Ha ,&nbsp;Sung Wook Lee ,&nbsp;In Guk Hwang ,&nbsp;Dong Kyu Kim","doi":"10.1016/j.ijheatmasstransfer.2025.127073","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127073","url":null,"abstract":"<div><div>This study presents a thermal-fluid analysis of an electric vehicle (EV) powertrain to evaluate the effectiveness and limitation of oil cooling. A validated numerical model was developed to investigate oil flow behavior, churning effects, and temperature distribution. Results show uneven oil distribution in the motor chamber. Only 22.6 % of the cooling oil reached the drive-end winding, while 46 % reached the non-drive end. As a result, the drive end experienced a 4.2 % higher temperature than the non-drive end. The stator temperature was 4.9 % higher than the windings, and the rotor exhibited the highest temperature due to inefficient heat dissipation. Additionally, oil recirculation from the reducer (0.02 L/s) reduced cooling efficiency, particularly under high-load conditions. These findings provide critical insights into the thermal challenges of EV powertrains and serve as a foundation for optimizing oil flow, developing hybrid cooling strategies, and improving thermal management in next-generation EVs.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"246 ","pages":"Article 127073"},"PeriodicalIF":5.0,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143799732","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}

{"title":"Enhanced subcooled flow boiling in microchannels integrated with nanoporous graphene coatings of distinctive wettability","authors":"Edmund Chong Jie Ng,&nbsp;Yew Mun Hung","doi":"10.1016/j.ijheatmasstransfer.2025.127065","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127065","url":null,"abstract":"<div><div>Subcooled flow boiling in microchannel presents a promising solution for efficient electronics cooling. This study explores the use of graphene nanoplatelets (GNPs) as a nanoporous surface coating to leverage the ultrafast water permeation and variable wettability properties of graphene in subcooled flow boiling through microchannels. The performance of GNPs coatings is evaluated using metrics such as the Nusselt number, pumping power, flow resistance, and performance evaluation criterion. The results demonstrate that the base GNPs coating, exhibiting dual wetting characteristics due to its synergistic combination of hydrophobicity and high surface roughness, outperforms both purely superhydrophilic and superhydrophobic GNPs coatings. The base GNPs coating achieves an impressive 143% increase in the Nusselt number and reduces the surface temperature by up to 25°C. However, the enhanced boiling performance with the base GNPs comes at the expense of increased pumping power, analogous to the use of inserts in channel flow. The improved heat transfer is coupled with higher flow resistance and energy consumption, leading to a performance evaluation criterion value well below unity. This study provides interesting insights into the application of GNPs in subcooled flow boiling in microchannels to improve the efficiency of electronics cooling.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"246 ","pages":""},"PeriodicalIF":5.0,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143799182","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}

{"title":"Thermocapillary instabilities in thin liquid films on a rotating cylinder","authors":"Souradip Chattopadhyay ,&nbsp;Amar K. Gaonkar ,&nbsp;Hangjie Ji","doi":"10.1016/j.ijheatmasstransfer.2025.127033","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127033","url":null,"abstract":"<div><div>Thin liquid films flowing along rotating cylinders are crucial in many industrial processes such as centrifugal thin-film evaporators. The thermocapillary instability in these films often leads to operational inefficiencies and stability concerns. To improve the design and operation of these systems under thermal effects, achieving a uniform distribution of the coating layer is crucial. This challenge becomes even more complex when the cylinder is simultaneously heated and rotated. A comprehensive understanding of these coupled effects is essential for uplifting the efficiency and effectiveness of these systems in practical applications. In this study, we present a model for a thin liquid film flowing along the inner surface of a rotating cylinder subjected to nonuniform heating. Using a long-wave approximation to describe interface dynamics, our study formulates a full lubrication equation incorporating thermal boundary conditions, nonlinear curvature terms, and rotational effects. Linear stability analysis indicates that the Rayleigh-Plateau instability can be suppressed by rotating the cylinder. When the wall is uniformly heated, the reinforced instability can also be suppressed by introducing rotation. Additionally, we investigate the influence of thermocapillarity and rotation on wave speed and the stability of traveling wave solutions. Furthermore, we numerically study the self-similar solution in plug formation and obtain the scaling <span><math><msup><mrow><mfenced><mrow><msub><mrow><mi>t</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>−</mo><mi>t</mi></mrow></mfenced></mrow><mrow><mn>1</mn><mo>/</mo><mn>5</mn></mrow></msup></math></span>, where <span><math><msub><mrow><mi>t</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> is the choke time. We find the exponent 1/5 is independent of rotation but <span><math><msub><mrow><mi>t</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> increases with higher rotation. Numerical simulation reveals that nonuniform heating exacerbates surface wave instability and plug formation (or choke behavior), while cylinder rotation can potentially delay plug formation. Our analysis shows that an increasing Biot number can induce choke behavior in a uniformly heated cylinder, but the introduction of rotation can delay the onset of choking.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"246 ","pages":"Article 127033"},"PeriodicalIF":5.0,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143799729","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}

{"title":"Additively manufactured inconel 718 vapor chamber with conformal micro-pillar wicks: A low temperature concept demonstration","authors":"Adnen Mezghani ,&nbsp;Corey J. Dickman ,&nbsp;Edward W. Reutzel ,&nbsp;Abdalla R. Nassar ,&nbsp;Douglas E. Wolfe","doi":"10.1016/j.ijheatmasstransfer.2025.127056","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127056","url":null,"abstract":"<div><div>Effective thermal management is crucial in hypersonic flight (Mach &gt; 5) due to extremely high aerodynamic heating located at leading edges, and both passive and active thermal protection systems (TPS) have been used to address this. Among passive TPS options are two-phase thermal management systems, such as heat pipes (HP) and vapor chambers (VC), which can realize a considerable reduction in steady-state leading edge temperature owing to their extremely high heat transfer capability. This leads to reduction in complexity and cost of TPS structure and material requirements. However, conventional HP and VC fabrication methods require multiple manufacturing and assembly steps, limiting their design space. Alternatively, utilizing additive manufacturing (AM) for fabrication can bypass conventional manufacturing limitations and enable structural members with intricate internal channels and topologically optimized shapes. AM can, therefore, unveil a larger design space for tailored leading edge concepts with an integrated passive TPS. This work demonstrates the design, fabrication and testing of a notional methanol-filled Inconel 718 VC with a conformal micro-pillar wick fabricated via laser-beam powder bed fusion AM. This serves as a proof of concept and establishes a foundation for design and fabrication of high-temperature additively manufactured sodium-filled leading edge VCs.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"246 ","pages":"Article 127056"},"PeriodicalIF":5.0,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143799731","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}

{"title":"Multiphase flow and interface dynamics in a blast furnace hearth: Effects of slag viscosity and coke diameter","authors":"Dong Jo Lee ,&nbsp;Hyun Sik Yoon ,&nbsp;Adarsh Rajasekharan Nair ,&nbsp;Min IL Kim","doi":"10.1016/j.ijheatmasstransfer.2025.127085","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127085","url":null,"abstract":"<div><div>This study numerically investigates the effects of slag viscosity (<span><math><msub><mi>μ</mi><mi>s</mi></msub></math></span>) and coke diameter (<span><math><msub><mi>D</mi><mi>P</mi></msub></math></span>) on the behavior of gas-slag and slag-iron interfaces, as well as the mass flow rates of slag and iron, in a three-dimensional (3D) full-scale blast furnace hearth model with four tapholes undergoing tapping and plugging cycles. This study introduces new perspectives by focusing on the bifurcation behavior of interface evolution, the classification of two distinct regimes in temporal levels, and circumferential variations in interface dynamics along the side wall. The slag-iron interface exhibited linear descent followed by saturation, while the gas-slag interface underwent linear descent followed by acceleration. Bifurcation at the onset of slag drainage, occurring earlier with larger <span><math><mrow><msub><mi>D</mi><mi>P</mi></msub><mspace></mspace></mrow></math></span>and lower <span><math><msub><mi>μ</mi><mi>s</mi></msub></math></span>, marked a critical shift in dynamics. Before bifurcation, <span><math><mrow><msub><mi>D</mi><mi>P</mi></msub><mspace></mspace></mrow></math></span>governed interface descent; after bifurcation, <span><math><mrow><msub><mi>μ</mi><mi>s</mi></msub><mspace></mspace></mrow></math></span>dominated, lowering pressure and increasing the pressure gradient near the taphole. These findings include novel insights into localized dynamics, revealing sharper circumferential gradients under conditions of higher <span><math><mrow><msub><mi>μ</mi><mi>s</mi></msub><mspace></mspace></mrow></math></span>and smaller <span><math><msub><mi>D</mi><mi>P</mi></msub></math></span>. Despite variations, slag and iron layer thickness ratios remained stable, reflecting their independence from <span><math><mrow><msub><mi>μ</mi><mi>s</mi></msub><mspace></mspace></mrow></math></span>and <span><math><msub><mi>D</mi><mi>P</mi></msub></math></span>. Additionally, a critical intersection point in mass flow rates was identified, where slag flow surpassed iron flow. This point, delayed under conditions of higher <span><math><mrow><msub><mi>μ</mi><mi>s</mi></msub><mspace></mspace></mrow></math></span>and smaller <span><math><msub><mi>D</mi><mi>P</mi></msub></math></span>, highlighted the influence of reduced fluidity on two-phase outflow dynamics. These findings highlight the potential of optimizing <span><math><mrow><msub><mi>μ</mi><mi>s</mi></msub><mspace></mspace></mrow></math></span>and <span><math><mrow><msub><mi>D</mi><mi>P</mi></msub><mspace></mspace></mrow></math></span>to enhance fluidity, production, energy efficiency and sustainability in blast furnace operations.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"246 ","pages":"Article 127085"},"PeriodicalIF":5.0,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143799733","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}

{"title":"A novel vapor chamber with gradient capillary wick and larger expansion area","authors":"Shichao Bu ,&nbsp;Haoran Li ,&nbsp;Xiaoping Yang ,&nbsp;Yonghai Zhang ,&nbsp;Kaiwen Duan ,&nbsp;Hongwei Bai ,&nbsp;Jinjia Wei","doi":"10.1016/j.ijheatmasstransfer.2025.127021","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127021","url":null,"abstract":"<div><div>As chip integration and performance increased, power consumption grew, making thermal management critical. While vapor chambers offered efficient heat transfer, uniform heat distribution, and simple structures, the capillary force of grooved and mesh designs were insufficient to meet higher cooling demands, highlighting the need for more efficient technologies. This study presents a longitudinally gradient sintered capillary copper-based vapor chamber to overcome the limitations of traditional grooved and mesh structures, enhancing liquid transport and accelerating the internal cycle for improved liquid supply to the evaporation zone. The working fluid employed in the experimental setup consisted of deionized water, making the design suitable for higher heat flux and power conditions. Thermal characterization of the vapor chamber was conducted through a liquid cooling plate, and the effects of different inclination angles and coolant temperatures on performance were systematically studied. Experimental results showed that inclination angle had little effect on performance, with thermal resistance increasing by only 0.007 K/W when operated vertically compared to horizontally. Additionally, raising the coolant temperature significantly improved heat transfer performance, reducing thermal resistance by 26.1 % at 40 °C compared to 20 °C. Furthermore, Experimental results demonstrated that the vapor chamber maintained stable functionality under power inputs reaching up to 1200 W. corresponding to a heat flux of 240 W/cm², at this time, the thermal resistance was 0.047K/W, indicating its potential for managing extremely high-power chips.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"246 ","pages":""},"PeriodicalIF":5.0,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143799534","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}

{"title":"Experimental investigation on the startup behavior and visualization of dual-evaporator loop heat pipes","authors":"Andhy M. Fathoni ,&nbsp;Priska A. Hendrayanto ,&nbsp;Ranggi S. Ramadhan ,&nbsp;Nandy Putra","doi":"10.1016/j.ijheatmasstransfer.2025.127053","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127053","url":null,"abstract":"<div><div>This study investigates the startup behavior and flow dynamics of a dual-evaporator loop heat pipe (DE-LHP) using neutron radiography. The DE-LHP is designed to overcome the challenges of efficiently managing multiple heat sources. Neutron radiography allows visualization of the liquid and vapor distributions, revealing phenomena like vapor backflow, liquid carryover, and heat leakage. Experiments were conducted with various heat load configurations, including balanced and unbalanced distributions, and different geometric orientations. The results show that at a balanced heat load (120 W total), the system reaches steady-state in 500 s with a thermal resistance of 0.14 °C/W while the highest thermal resistance of 0.64 °C/W was observed in the unequal heat load case of 56 W. The unbalanced heat load increases the thermal resistance and decreases the thermal efficiency due to uneven heat distribution and incomplete startup. Orientation studies show that the inclination of the DE-LHP reduces the liquid carryover and vapor backflow, improving the heat transfer efficiency. These findings provide valuable insights for optimizing the DE-LHP design and improving the thermal management system.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"246 ","pages":""},"PeriodicalIF":5.0,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143799181","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}

{"title":"Study on the friction resistance characteristics of supercritical CO2 correlating with heat transfer behavior in vertical tubes","authors":"Wenhua Wu ,&nbsp;Chenshuai Yan ,&nbsp;Xinyi Zhang ,&nbsp;Xiaojuan Niu ,&nbsp;Haisong Zhang","doi":"10.1016/j.ijheatmasstransfer.2025.127057","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127057","url":null,"abstract":"<div><div>The supercritical carbon dioxide (scCO₂) Brayton cycle has attracted significant attention because of high cycle efficiency and compact layout. As one of the critical issues, the characteristic of scCO₂ flow resistance, which affects compression work and thermal efficiency, is essential to the design of the cycle components. Firstly, the heat transfer and pressure drop characteristics of scCO₂ flowing vertically upwards in the heated tubes are experimentally and numerically investigated. The experimental parameters span pressures of 7.5−16 MPa, mass fluxes of 500−1530 kg/m²s, and heat fluxes of 20−250 kW/m². Then, the relationship between friction pressure drop and supercritical heat transfer behavior is numerically explored. We discover that both the friction pressure drop and friction factor are closely related to the supercritical heat transfer behavior. Exactly, supercritical heat transfer deterioration (HTD) can lead to a large friction pressure drop. We analyze the mechanism of heat transfer inducing friction pressure drop change according to the assumption of supercritical pseudo-phase change, where similar to the film boiling heat transfer at subcritical pressure, a vapor-like layer attaching to heating surface and core liquid-like phase. Owing to the large thermal resistance induced by the vapor-like layer when HTD occurs, the core liquid-like cannot be heated smoothly. That results in a high molecular viscosity level. Ulteriorly, the friction pressure drop rises. Considering the correlation between frictional pressure drop and scCO₂ heat transfer behavior, a newly modified Filonenko correlation is proposed to predict the friction factor of scCO₂. In contrast to the experimental data, the <em>e</em>_ME, <em>e</em>_MAE and <em>e</em>_RMSE of the new correlation are 3.6%, 16.41%, and 19.88%, respectively, which shows the highest prediction accuracy compared with the friction factor correlations in previous literature.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"246 ","pages":"Article 127057"},"PeriodicalIF":5.0,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143791076","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}

{"title":"Characterization of semi-open liquid desiccant cycle energy efficiency in ventilation air treatment","authors":"Rohit Bhagwat ,&nbsp;Raju Bhatia ,&nbsp;Michael Schmid ,&nbsp;Sidharth Sanadhya ,&nbsp;Ashwani Verma ,&nbsp;Saeed Moghaddam","doi":"10.1016/j.ijheatmasstransfer.2025.127061","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127061","url":null,"abstract":"<div><div>Efficient moisture removal from air without subcooling using liquid desiccants represents a major advancement in energy-efficient cooling, particularly through the separate sensible and latent cooling (SSLC) process. However, developing a high-performance, robust liquid desiccant dehumidification cycle remains challenging. Traditional open desiccant cycles rely on outdoor air to remove moisture from the desiccant solution in the regenerator, but this also extracts significant sensible heat, reducing overall efficiency. This study investigates a semi-open absorption cycle that eliminates the need for scavenging air, addressing a key inefficiency of conventional systems. An experimental system was tested under varying outdoor air conditions, demonstrating substantial performance improvements. The semi-open cycle significantly reduced sensible heat loss compared to traditional systems while maintaining strong moisture removal capabilities. Notably, it achieved a dehumidification coefficient of performance (COP) of up to 0.9, with peak latent cooling capacity observed at higher inlet air dew points. These findings underscore the semi-open cycle's potential for enhancing energy efficiency in dehumidification, particularly in regions with high latent loads.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"246 ","pages":"Article 127061"},"PeriodicalIF":5.0,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143791075","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}

{"title":"Experimental studies of saturated pool boiling heat transfer and critical heat flux on scalable etched copper surfaces for R-134a and low-GWP refrigerants R-1336mzz(E) and R-1336mzz(Z)","authors":"Yiyang Chen ,&nbsp;Vishwanath Ganesan ,&nbsp;Mohammad Jalal Inanlu ,&nbsp;Haoyun Qiu ,&nbsp;Bakhshish Preet Singh ,&nbsp;Shuoning Shi ,&nbsp;Wuchen Fu ,&nbsp;Nenad Miljkovic","doi":"10.1016/j.ijheatmasstransfer.2025.126958","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.126958","url":null,"abstract":"<div><div>Enhancing pool boiling heat transfer with low-Global Warming Potential (low-GWP) refrigerants is increasingly becoming an important topic in the heating, ventilation, air conditioning, and refrigeration (HVAC&amp;R) sector. This study develops two scalable etching techniques for copper (Cu) tubes, with surface structures having characteristic length scales of <span><math><msub><mi>R</mi><mtext>structure</mtext></msub></math></span> = 16 µm and 12 µm for FeCl₃ and H₂O₂ etch chemistries, respectively. In saturated pool boiling experiments for refrigerants, the etched Cu tubes are shown to increase the heat transfer coefficient (HTC) by activating a wider range of cavities and enhancing active nucleation site density. When tested with low-GWP refrigerant R-1336mzz(E), the FeCl₃ and the H₂O₂ Etched Cu tubes increased the HTC to 1.9X and 2.0X compared to plain Cu tubes, respectively. The HTC enhancements observed with both etched surfaces agree well with the newly developed modified Cooper correlation for structured surfaces with a mean absolute error (MAE) of 5.5 %. The critical heat flux (CHF) for both etched Cu tubes during low-GWP R-1336mzz(E) and R-1336mzz(Z) saturated pool boiling was also tested, showing lower CHFs when compared to plain Cu tube samples because of reduced wetting in the Cassie-Baxter state. The experiments also show that temperature fluctuations at the hot water outlet increase with higher average wall superheat as CHF is approached. When combined with optical imaging, the results clearly reveal the transition in the boiling regimes. This study provides insights into scalable fabrication methods using chemical processing for the creation of enhanced external structures for refrigerant pool boiling, and offers guidance for the design of submerged or flooded shell-and-tube heat exchangers.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"246 ","pages":"Article 126958"},"PeriodicalIF":5.0,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143785808","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}