International Journal of Heat and Fluid Flow最新文献

{"title":"A novel strategy for numerical analysis of nonharmonic laser-induced acoustic streaming","authors":"Runjia Li ,&nbsp;Feng Lin ,&nbsp;Jiming Bao ,&nbsp;Dong Liu","doi":"10.1016/j.ijheatfluidflow.2025.109802","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109802","url":null,"abstract":"<div><div>Acoustic streaming in microfluidics has traditionally been driven by harmonic acoustic waves generated from on-chip ultrasound transducers. Laser-induced acoustic streaming (laser streaming) offers a transducer-free, light-driven approach to microfluidic actuation. However, the highly nonharmonic nature of laser streaming hinders its analysis using conventional methods. This work introduces a novel strategy to bridge this gap and enables quantitative numerical modeling of laser streaming. This method decomposes the nonharmonic ultrasonic field generated by pulsed laser heating into harmonic components using Fourier series expansion. The dominant components, selected from energy spectrum analysis, are then solved using successive approximations to yield the time-averaged streaming force, which incorporated into second-order streaming equations to determine the streaming field. The simulation results demonstrate good agreement with experimental data and other numerical models. This new strategy significantly reduces the computational costs while enhancing insights into the laser streaming physics. It also provides a versatile tool for analyzing general forms of acoustic streaming induced by nonharmonic sources.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"114 ","pages":"Article 109802"},"PeriodicalIF":2.6,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143644048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of the three-phase spiral countercurrent heat exchange and fluid dynamics in an innovative high-temperature particle waste heat recovery system","authors":"Anxiang Shen ,&nbsp;Tao Wang ,&nbsp;Huijie Xu ,&nbsp;Yutao Shi ,&nbsp;Yang Chen ,&nbsp;Jianqiu Zhou","doi":"10.1016/j.ijheatfluidflow.2025.109814","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109814","url":null,"abstract":"<div><div>A novel steel slag rapid cooling and heat recovery system has been proposed. Gas-liquid–solid coupled heat transfer is adopted to recover waste heat. It only needs very little air velocity and air volume, which greatly reduces the energy consumption. The key component (the spiral coil) has been simulated to study the kinetic energy transfer and heat exchange process. This study examines both the heat transfer characteristics and the fluid dynamics of particles throughout the entire spiral coil. The distribution of particles across the flow path has also been subjected to analysis. Additionally, this study has focused on evaluating the heat transfer efficiency. The performance of the novel system is evaluated with different parameters. It shows that When <em>m</em>_slag is 0.5 kg/s, <em>u</em>_{air_in} is 1 m/s, the system waste heat recovery performance reaches the maximum (<em>Q</em>_water = 16.33 kW, <em>Q</em>_air = 1.08 kW, <em>Q</em>_blower = −0.82 kW). The present work provides a theoretical basis for further improving the steel slag waste heat recovery efficiency.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"114 ","pages":"Article 109814"},"PeriodicalIF":2.6,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143637167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computational investigation of heat transfer and frictional loss of fin-tube heat exchanger with delta winglet and shear-thinning fluid","authors":"Dheeraj Kumar ,&nbsp;Amaresh Dalal","doi":"10.1016/j.ijheatfluidflow.2025.109800","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109800","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The flow characteristics of a shear-thinning fluid and their significant impacts on the heat transfer and pressure drop effectiveness of a finned-tube heat exchanger (FTHE) incorporating delta winglet vortex generators (DWVG) have been analyzed numerically. This study employed a three-dimensional numerical approach taking into account only the laminar flow of incompressible and single-phase fluid and disregarding the impact of body forces, compressibility, and radiation. The ANSYS FLUENT 2021 R1 was used to simulate the computational domain. Specifically, the flow domain comprises a rectangular duct containing three rows of inherent cylinders and punched delta winglets mounted at various attack angles (&lt;span&gt;&lt;math&gt;&lt;mi&gt;β&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;) (160°, 165°, and 170°). The simulation was conducted over a range of Reynolds numbers (Re) from 50 to 200, using a carboxymethyl cellulose (CMC) aqueous solution at a concentration of 2000 ppm as a shear-thinning fluid. The outcomes of present study in terms of the average Nusselt number (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;N&lt;/mi&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;u&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;), apparent friction factor (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;f&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;), and quality factor (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;Q&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;f&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;) were compared to those of a channel with a rectangular winglet vortex generators (RWVG) and a base channel without a DWVG. The results indicated that, compared to the rectangular winglet, the implementation of the DWVG caused a 28% decrease in &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;N&lt;/mi&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;u&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and a 34% decrease in &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;f&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;, while &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;Q&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;f&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; increased by 9%. In contrast, compared to the base channel, &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;N&lt;/mi&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;u&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;f&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;, and &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;Q&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;f&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; are increased by 81%, 33%, and 36%, respectively. The results indicate that, compared to DWVGs, RWVGs enhance heat transfer, but this comes with a significant pressure drop. Using aqueous solutions of carboxymethylcellulose as a working fluid in a channel with DWVGs enhances the &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;N&lt;/mi&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;u&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and the &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;Q&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;f&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; by 147% and 104% respectively and decreases the &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;f&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; by 40% compared to w","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"114 ","pages":"Article 109800"},"PeriodicalIF":2.6,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143631755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Production and survival of early turbulence due to flow modulation at the duct inlet","authors":"Md Ashfaqul Bari,&nbsp;Manuel Münsch,&nbsp;Jovan Jovanović,&nbsp;Antonio Delgado","doi":"10.1016/j.ijheatfluidflow.2025.109792","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109792","url":null,"abstract":"<div><div>The paper reports a fully resolved numerical simulation of turbulent duct flow developing under complex inlet flow conditions at very low Reynolds number <span><math><mrow><mi>R</mi><msub><mrow><mi>e</mi></mrow><mrow><mi>m</mi></mrow></msub><mo>=</mo><mn>1250</mn><mo>−</mo><mn>4070</mn></mrow></math></span> based on the channel width and bulk velocity. Turbulence was initiated by inflectional instabilities created at the duct center owing to the special inlet design. All simulations were performed using the open-source software OpenFOAM. Computations reveal that turbulence persisted over more than 60 turnover time. Its statistical features were characterized by distributions of the mean flow and turbulent stresses at multiple duct locations. The turbulent stresses were used to analyze the anisotropic nature of turbulence by evaluating trajectories of across the anisotropy-invariant map which bounds all realizable states of turbulence. The limiting behavior of turbulence stresses reveals explosive production of the dissipation at the wall. This evidence suggests that the chief mechanisms involved during the transition process and self-maintenance of turbulence at very low Reynolds numbers is related to the dynamics of the turbulent dissipation rate which attains the maximum amplification by approaching the two-component isotropic state at the wall.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"114 ","pages":"Article 109792"},"PeriodicalIF":2.6,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143611586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"To what extent does local oscillation influence the thermal performance of finned PCM-based energy storage systems: A numerical study","authors":"Amir Hossein Vakilzadeh ,&nbsp;Amirhossein Bagheri Sarvestani ,&nbsp;Kourosh Javaherdeh ,&nbsp;Reza Kamali ,&nbsp;Satyam Panchal","doi":"10.1016/j.ijheatfluidflow.2025.109798","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109798","url":null,"abstract":"<div><div>Enhancing the thermal performance of phase change materials (PCMs) is vital for improving the efficiency of energy storage systems. While fins are widely used to expedite the melting process by boosting thermal conductivity, their effectiveness diminishes as melting progresses and natural convection becomes dominant. Meanwhile, local mechanical oscillation has emerged as a promising technique to further accelerate melting, though its isolated use has been the primary focus of prior studies. The combined effect of fins and local oscillation, particularly their interaction in influencing the heat transfer dynamics of PCM, remains unexplored. Thus, this study develops a numerical model to investigate the interaction between various fin configurations (namely, sinusoidal, and positive/negative straight fins) and local oscillation within a finned rectangular enclosure. Moreover, the local oscillator’s placement on the hot wall, as well as its proximity to the fins, are among key factors analyzed. The results demonstrate that negative rectangular fins consistently deliver superior thermal performance, while the effectiveness of local oscillation diminishes when placed between fins, particularly as the melting front progresses. The optimal configuration is a vertical oscillator positioned at the base of the hot wall near a negative fin, which achieves a 64.3 % reduction in melting time. Notably, as the lower fin is installed closer the bottom wall of the enclosure, two distinct mechanisms arising from extension of the heating area and local flow stimulation by the oscillator plate, though differing fundamentally, result in similar effects during the later stages of the melting process, thereby diminishing the overall influence of localized oscillation on the melting process.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"114 ","pages":"Article 109798"},"PeriodicalIF":2.6,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143611585","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study of the flow pattern and heat transfer characteristics of the refrigerant flow condensation through metal foam inserts","authors":"Mohamad Vahid Rafieinejad ,&nbsp;Rasool Mohammadi ,&nbsp;Mohammad Ali Akhavan-Behabadi ,&nbsp;Behrang Sajadi","doi":"10.1016/j.ijheatfluidflow.2025.109801","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109801","url":null,"abstract":"<div><div>Metal foams have shown remarkable effects on heat transfer improvement in diabatic two-phase flows, especially for refrigeration applications. The present experimental study addresses the flow condensation regimes and characteristics of R134a in 10 PPI and 20 PPI copper foam inserts inside 8 mm i.d. tubes. The flow pattern maps were extracted under uniform wall temperature boundary conditions for mass flux 75–150 kg m⁻² s⁻¹. In this study, three distinct flow regimes are introduced in the presence of metal foams: stratified–wavy, wavy–annular, and annular. Although the outcomes prove that the PPI of metal foam is a determining factor for the distribution of flow patterns on the map, the stratified–wavy regime is majorly captured at low-quality and low-mass flux zones, while the annular pattern is only observable at high-quality and high-mass flux zone of the maps. The flow maps revealed that the annular to wavy–annular regime transition withdraws from a vapor quality of 0.6 to approximately 0.3 at the highest mass flux. Similarly, the wavy–annular to stratified–wavy pattern transition falls back from a quality of 0.7 to around 0.35 at the mass flux of 100 kg m⁻² s⁻¹. In addition, this research investigates how vapor quality, mass flux, and foam pore density affect heat transfer and pressure losses during condensation. An intensive correlation between heat transfer coefficient and flow variables of mass flux and vapor quality is noted. 20 PPI foam owns larger heat transfer coefficients than 10 PPI, while the pressure drop within the 20 PPI insert is significantly larger than in 10 PPI. The metal foam inserts helped enhance the heat transfer coefficient by about 220 %. The findings show that the pressure drop progressively elevates as the quality of vapor and mass flux rise. The use of copper foam inserts of 20 PPI, particularly at high vapor qualities, is beneficial in applications where heat transfer enhancement is a priority.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"114 ","pages":"Article 109801"},"PeriodicalIF":2.6,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143591552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characteristics of turbulent Taylor-Couette flow of low-viscosity fluid on plastron-covered superhydrophobic surface","authors":"Seongbin Ahn ,&nbsp;Sungwon Jo ,&nbsp;Woobin Song ,&nbsp;Haeyeon Lee ,&nbsp;Garam Ku ,&nbsp;Minjae Kim ,&nbsp;Dong Rip Kim ,&nbsp;Simon Song","doi":"10.1016/j.ijheatfluidflow.2025.109805","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109805","url":null,"abstract":"<div><div>This study introduces a newly developed Taylor-Couette (TC) flow system designed to investigate flow dynamics in low-viscosity fluids, such as water, under fully turbulent conditions. To ensure precise drag measurements, the system accounts for mechanical friction from bearings and von Kármán torque (the torque generated by fluid motion in the gap between the end-plates of the cylinders), enabling accurate evaluation of TC torque. Utilizing exact counter-rotation conditions that produce featureless turbulence, we explored the drag reduction capabilities of a hybrid superhydrophobic surface (SHS) mounted on the inner cylinder, alongside visualizing the resultant plastron formations. For the first time, two-dimensional particle image velocimetry (2D PIV) was used near the wall to quantify drag reduction based on total shear stress derived from flow visualization on SHS in a TC flow system. The plastron-induced slip conditions led to significant shifts in bulk velocity within the TC gap. A detailed analysis of Reynolds stresses revealed substantial modifications in flow dynamics, including reduced peak Reynolds stress and increased near-wall Reynolds stress, while total shear stress decreased across the gap. Additionally, simultaneous visualization and assessment of the plastron provided novel insights into its role in enhancing drag reduction. These findings underscore the importance of accounting for bearing mechanical friction in torque measurements when using low-viscosity fluids and confirm the effectiveness of SHS in modifying turbulence for drag reduction. The results highlight the TC-PIV system’s robust capability for detailed fluid dynamics investigations and its potential to inform hydrodynamic drag reduction strategies.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"114 ","pages":"Article 109805"},"PeriodicalIF":2.6,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143579883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bioinspired spider-web microchannel with five-input-four-output manifold: Enhanced thermal performance for 10,000 kW/m2 chip-scale embedded cooling","authors":"Jun Du ,&nbsp;Yilin Fang","doi":"10.1016/j.ijheatfluidflow.2025.109794","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109794","url":null,"abstract":"<div><div>Rapid advancements in high-heat flow density electronic chips have made the enhancement of heat sink thermal performance a crucial aspect of research aimed at efficient chip cooling. This paper uses the structure of a spider web to come up with an embedded flow-shape cooling method that can remove 10,000 kW/m² of heat. The temperature rise and junction temperature must be less than 60 °C and 85 °C, respectively. We compared two heat sinks with different flow shapes. The heat sinks’ thermal resistance, pressure drop, temperature distribution, temperature rise, junction temperature, and coefficient of performance (COP) of heat dissipation at flow rates of 0.2–0.6 L/min were reported using simulation calculations. As the inlet flow rate went up, the results showed that the temperature distribution became more uniform, and the average outlet temperature, temperature rise, temperature standard deviation, and junction temperature all went down. Notably, the five-input-four-output manifold design exhibited superior heat transfer efficiency and temperature uniformity compared to single-outlet structures, with lower thermal resistance. Under high heat flux conditions, the maximum temperature standard deviation was recorded at 1.18 °C, with a minimum of just 0.2 °C. With a pressure drop of 37.3 kPa and a flow rate of 0.6 L/min, the effective thermal resistance was a mere 0.047 (cm²·°C)/W. However, it is important to note that both radiators saw a bigger pressure drop and a lower COP as a result of the increased flow rate.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"114 ","pages":"Article 109794"},"PeriodicalIF":2.6,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143807364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design criteria and performance optimization of high-power micro heat sinks","authors":"Jiali Zhuo,&nbsp;Yuling Zhai,&nbsp;Hao Huang,&nbsp;Zhouhang Li","doi":"10.1016/j.ijheatfluidflow.2025.109797","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109797","url":null,"abstract":"<div><div>A three-dimensional mathematical model of micro heat sinks was developed to achieve efficient thermal management in microelectronic devices. Comprehensive design criteria based on the theory of heat transfer enhancement at the micro-scale are also proposed. On this basis, the size of the microchannel structure is designed, considering a fixed heat transfer area and heat flux. Then, a combination of a response surface approximation, an non-dominated sorting genetic algorithm, and <em>k</em>-means clustering are used to optimize the width and height of each microchannel. The designed structure size is combined with supercritical carbon dioxide (SCO₂) working fluid to optimize the thermal performance of micro heat sinks. The optimization results demonstrated that the clustering point I of the evaluation factor <em>j</em>/<em>f</em>_ave increased by 4.11 %, while the wall temperature <em>T_w</em> decreased by 4.69 %. Compared to the SCO₂ scenario, the pump power and total entropy generation were respectively 61.63 % and 6.9 % lower than those of water with a mass flow rate of 6000 kg/m²·s and an inlet temperature of 293 K. For inlet temperatures ranging from 303 K to 307 K, the evaluation factor values reported were 0.2405, 0.2018, 0.1045, 0.1453, and 0.1747 under a pressure of 7.6 MPa and flow rate of 4000 kg/m²·s. For mass flow rates ranging from 3000 kg/m²·s to 6000 kg/m²·s, values of <em>j</em>/<em>f</em>_ave were 0.0591, 0.1045, 0.1515, and 0.2084, indicating good thermal performance at relatively high mass flow rates. It was noted that as the distance from the critical point of the channel increases, the overall heat transfer performance is improved when the inlet temperature is less than the critical temperature.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"114 ","pages":"Article 109797"},"PeriodicalIF":2.6,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143579884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental visualization of dry regions formation for Falling-Film flow patterns","authors":"Prudviraj Kandukuri,&nbsp;Sandip Deshmukh,&nbsp;Supradeepan Katiresan","doi":"10.1016/j.ijheatfluidflow.2025.109803","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109803","url":null,"abstract":"<div><div>Water is essential for humans in everyday life, and plenty of fresh water is required for agricultural, chemical, industrial, and other domestic uses. Water scarcity is becoming increasingly prevalent in many regions and countries as they advance their respective growth lines. The predominant method employed in thermal desalination plants is the falling-film process due to its operational advantages. The present study examines<!--> <!-->the mapping of diverse flow patterns for heat transfer mechanisms across the horizontal tube bundle. An experimental test facility is developed, and a series of visualization experiments are conducted. The FLIR E60 infrared camera is employed to examine the liquid film behavior for different temperature profiles. The findings revealed that the droplet flow pattern induces wave-like wetting, whereas the column flow pattern induces liquid ring wetting on the tube wall. The tube wall temperature attains its maximum during droplet flow, regardless of the chosen tube spacing values. When the tube spacing is 10/20/30/40 mm, the maximum temperature of the liquid film is reached rapidly in the droplet flow, reaching values of 75.7 °C, 73 °C, 79.1 °C, 65.8 °C, 76.5 °C, 71.4 °C, 69.3 °C, and 74.2 °C, respectively, in comparison to other flow modes. The infrared photographic images show that the stabilizing tube has a faster heat transfer mechanism than the test tube. Furthermore, the liquid profile on the upper portion of the tube wall exhibits a faster evaporation rate than the lower one. The formation of dry spots on the test tubes and stabilizing tubes exhibited a distinct pattern due to<!--> <!-->distinct flow mode wetting phenomena for chosen working conditions. The research findings address various aspects of information on falling-film flow behavior and mapping of flow patterns to heat transfer mechanisms.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"114 ","pages":"Article 109803"},"PeriodicalIF":2.6,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143548914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}