International Journal of Heat and Fluid Flow最新文献_第2页

Experimental investigation of a bio-based commercial phase change material melting in an inclined rectangular enclosure

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2025-02-27 DOI: 10.1016/j.ijheatfluidflow.2025.109776

Casey J. Troxler, Andrew J. Heiles, Isabel Melendez, Sandra K.S. Boetcher

The interest in phase change materials (PCMs) for various engineering applications such as thermal management or energy storage has grown in recent years. In response, many different materials have been identified as viable PCMs in the literature, along with a proliferation of commercially available products. This research presents material property characterization and experimental data for one such commercial bio-based PCM, utilizing established analytical instruments and a common heat transfer experiment typically employed for the validation of enthalpy-porosity models. Melting within a 50 mm

\times

50 mm

\times

120 mm rectangular container subjected to an isothermal boundary is observed across a range of angles, from 30

°

to 90

°

as measured from the horizontal. A discussion of melting regimes and natural convection within vertical and inclined melting phase change problems is provided, while key influences on performance are identified. The impact of the change in incline on melting time is documented, with the largest effect being a 35% increase in melting speed from 90° to 30° at 47 °

C

and a 46% increase at 57 °

C

This study provides new results regarding the interaction between wall temperature and inclination during melting in rectangular enclosures, along with comprehensive validation data for evaluating numerical modeling methods.

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引用次数: 0

Directional riblets as an airfoil passive flow control mechanism

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2025-02-27 DOI: 10.1016/j.ijheatfluidflow.2025.109772

Zambri Harun , Ashraf Amer Abbas , Wan Aizon W. Ghopa , Taha Ghassan Taha , Morteza Khashehchi , Bagus Nugroho , Rey Chin

The effects of converging–diverging riblets (C–D riblets) on the surface of a flat-bottomed airfoil bump on the wind tunnel wall is investigated experimentally. Here long strips of C–D riblets with viscous height of

h^{+}

\approx

20–23) are applied and cover the surface of approximately 60% in chord percentage of the surface of a flat-bottomed airfoil bump resulting in counter rotating vortices under an adverse pressure gradient (APG) environment. The use of C–D riblets significantly affects the streamwise mean velocity profile and the thickness of the boundary layer

δ

. Increased drag is observed above the APG converging regions, while drag decreases above the APG diverging regions, with distinct vertical shifts in the mean velocity profile. Compared the to zero pressure gradient (ZPG) riblet cases in the literature, these shifts are pushed further downwards for both APG riblets configurations. Premultiplied energy spectra also show notable differences from ZPG cases in the literatures. Here the results suggest that the adverse pressure gradient environment amplify the outer peak magnitude for both riblet configurations, indicating a higher occurrence of large-scale structure interactions (‘superstructure’) in the APG compared to the ZPG environments. Finally, scale decomposition analysis confirms that large-scales contribute to the outer peak of turbulence intensity across all surfaces, while small scales primarily influence the inner peak. Interestingly, for the APG converging riblet case, small scales also significantly contribute to the outer peak. These findings underscore the complex interplay of pressure gradient and riblet geometry in modulating turbulent boundary layer characteristics.

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引用次数: 0

Conservative Immersed Boundary Methods on Cartesian grids for inviscid compressible flows simulation

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2025-02-27 DOI: 10.1016/j.ijheatfluidflow.2025.109775

El Hadji Abdou Aziz Ndiaye , Jean-Yves Trépanier , Renan De Holanda Sousa , Sébastien Leclaire

This work introduces three conservative methods based on the Immersed Boundary Method. These methods make use of cut-cells to ensure the conservation properties in the numerical solution. However, since some cut-cells can be very small, they can significantly restrict the time step of an explicit time integration scheme. To circumvent this limitation, a semi-implicit treatment of the small cells is employed. The first method relies on a straightforward flux redistribution procedure that globally restores conservation on the cut-cells grid. The other two methods employ the local conservative discretization form of the finite volume method, along with optimization procedures, to ensure local conservation of the numerical solution within each cell. These methods have been tested on two-dimensional inviscid compressible flow problems, demonstrating results comparable to those obtained with the standard Cut-Cells method in terms of accuracy and conservation. Furthermore, the methods are stable and can be effectively used with an explicit time integration scheme without encountering any stability issues related to the small cut-cells.

{"title":"Conservative Immersed Boundary Methods on Cartesian grids for inviscid compressible flows simulation","authors":"El Hadji Abdou Aziz Ndiaye , Jean-Yves Trépanier , Renan De Holanda Sousa , Sébastien Leclaire","doi":"10.1016/j.ijheatfluidflow.2025.109775","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109775","url":null,"abstract":"<div><div>This work introduces three conservative methods based on the Immersed Boundary Method. These methods make use of cut-cells to ensure the conservation properties in the numerical solution. However, since some cut-cells can be very small, they can significantly restrict the time step of an explicit time integration scheme. To circumvent this limitation, a semi-implicit treatment of the small cells is employed. The first method relies on a straightforward flux redistribution procedure that globally restores conservation on the cut-cells grid. The other two methods employ the local conservative discretization form of the finite volume method, along with optimization procedures, to ensure local conservation of the numerical solution within each cell. These methods have been tested on two-dimensional inviscid compressible flow problems, demonstrating results comparable to those obtained with the standard Cut-Cells method in terms of accuracy and conservation. Furthermore, the methods are stable and can be effectively used with an explicit time integration scheme without encountering any stability issues related to the small cut-cells.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"114 ","pages":"Article 109775"},"PeriodicalIF":2.6,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511911","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}

引用次数: 0

Frequency analysis of flow and heat transfer near reattachment point behind a backward-facing step

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2025-02-27 DOI: 10.1016/j.ijheatfluidflow.2025.109771

Shunsuke Yamada, Yuki Funami, Hajime Nakamura

In this study, the nature of the flow and heat transfer near the flow reattachment point behind a backward-facing step was experimentally investigated at a Reynolds number of 5400. The unsteady fluctuations of the velocity and temperature were simultaneously measured by particle image velocimetry in a two-dimensional plane that contained three components (2D-3C PIV) and by high-speed infrared thermography. To evaluate the mechanism of the flow and heat transfer, the vorticity and heat transfer coefficients were calculated from the time history data for each velocity and temperature. Also, the spatial flow structure and the characteristic frequency of the flow and heat transfer fluctuations were investigated by using two-point correlation, a fast Fourier transform, and a continuous wavelet transform. These results showed that the characteristic frequencies for each velocity and heat transfer coefficient appeared near the wall. It was revealed that the temporal and spatial fluctuations of the heat transfer coefficient corresponded to that of the streamwise flow. From the time-moving averaging streamwise velocity and heat transfer with the conditional sampling, the zero-velocity line at the low nondimensional frequency of 0.06 fluctuated near the wall as time advance, and the high heat transfer appeared near the instantaneous reattachment point.

{"title":"Frequency analysis of flow and heat transfer near reattachment point behind a backward-facing step","authors":"Shunsuke Yamada, Yuki Funami, Hajime Nakamura","doi":"10.1016/j.ijheatfluidflow.2025.109771","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109771","url":null,"abstract":"<div><div>In this study, the nature of the flow and heat transfer near the flow reattachment point behind a backward-facing step was experimentally investigated at a Reynolds number of 5400. The unsteady fluctuations of the velocity and temperature were simultaneously measured by particle image velocimetry in a two-dimensional plane that contained three components (2D-3C PIV) and by high-speed infrared thermography. To evaluate the mechanism of the flow and heat transfer, the vorticity and heat transfer coefficients were calculated from the time history data for each velocity and temperature. Also, the spatial flow structure and the characteristic frequency of the flow and heat transfer fluctuations were investigated by using two-point correlation, a fast Fourier transform, and a continuous wavelet transform. These results showed that the characteristic frequencies for each velocity and heat transfer coefficient appeared near the wall. It was revealed that the temporal and spatial fluctuations of the heat transfer coefficient corresponded to that of the streamwise flow. From the time-moving averaging streamwise velocity and heat transfer with the conditional sampling, the zero-velocity line at the low nondimensional frequency of 0.06 fluctuated near the wall as time advance, and the high heat transfer appeared near the instantaneous reattachment point.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"113 ","pages":"Article 109771"},"PeriodicalIF":2.6,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143508339","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}

引用次数: 0

Size effect on the thermal response of aluminum profiles: Experimental and numerical simulation study

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2025-02-26 DOI: 10.1016/j.ijheatfluidflow.2025.109784

Junhao Gao, Jie Xu, Jin Lin, Shouxiang Lu

This study analyzes the thermal response characteristics of aluminum profile structures of various sizes under different heating conditions through a combination of small-scale and large-scale experiments. A three-dimensional numerical model was used to simulate heat transfer behavior across different sizes and heating scenarios for small-sized aluminum profiles. In the case of large-sized aluminum profiles, a two-dimensional numerical model incorporating coupled phase transitions was employed to investigate the effects of size on their thermal response in high-temperature environments. The results for small-sized aluminum profiles indicate that, for a fixed ratio of heating size to sample size, the maximum temperature at the backfire surface of the aluminum profiles increases with size under identical heating conditions. In contrast, the average temperature at the backfire surface remains relatively stable. This observation, validated by numerical simulations and theoretical analysis, highlights the influence of heating and sample size on the thermal response characteristics. For large-sized aluminum profiles, it was observed that their refractory properties varied with size under consistent heating conditions, with integrity failure time decreasing as the structural size increased. The reliability of the two-dimensional numerical simulations was confirmed by comparison with experimental data. Further investigations extended the analysis to a broader range of aluminum profile sizes and size ratios, revealing a logarithmic relationship between the integrity failure time of the profiles and their structural size and heating dimensions.

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引用次数: 0

Investigating the Evolution of arch temperature and prediction model for temperature rise of fire Smoke: Model testing of an Extra-Long highway tunnel with vertical shaft

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2025-02-22 DOI: 10.1016/j.ijheatfluidflow.2025.109781

Hui Li , Yuqing Xie , Zhiqiang Zhang , Rongjie Li , Heng Zhang

In order to investigate the characteristics of the arch temperature distribution of extra-long highway tunnel fire under the action of vertical shaft mechanical smoke exhaust, relying on the Yunshan Tunnel in Shanxi Province to carry out the physical model test of tunnel fire scaling under the vertical shaft mechanical smoke exhaust, to explore the influence of the vertical shaft structural parameters on the longitudinal temperature distribution of the tunnel, as well as the characteristics of the upstream and downstream tunnel smoke outlet attenuation of the temperature of the arch in the conditions of the different fire power and fire position, the results show that: the diameter of the shaft and the height of the smoke outlet upstream temperature has less influence on the temperature of the tunnel smoke outlet. The results show that the diameter and height of the shaft have less influence on the upstream temperature of the smoke outlet. For the downstream of the smoke outlet, the larger the diameter of the shaft, the faster the arch temperature decreases; the higher the height of the shaft, the lower the arch temperature at the downstream measurement points. The arch temperature upstream of the smoke outlet shows a significant exponential attenuation trend for different fire power and location, and the influence of smoke exhaust speed on the temperature attenuation is extremely small when the fire source is far away from the smoke outlet. On the contrary, the temperature attenuation of the arch downstream of the smoke outlet was significantly affected by the smoke exhaust speed and was not sensitive to the change of the distance between the fire source and the smoke outlet. At low wind speeds (≤13 m/s), the downstream temperature followed an exponential attenuation; while at high wind speeds (15 m/s), the attenuation pattern shifted to linear. Predictive equations for the temperature rise in the upstream and downstream arches of the smoke outlet were fitted for 94.9 kW and 158.1 kW fire power, which provided a theoretical basis for fire safety assessment.

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引用次数: 0

Simulation study on the influence of the combined application of melt shearing and electromagnetic field on the flow and temperature fields during Direct-Chill casting of 2024 aluminum alloy

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2025-02-21 DOI: 10.1016/j.ijheatfluidflow.2025.109782

Jinchuan Wang , Yubo Zuo , Qingfeng Zhu , Rui Wang , Xianliang Guo , Xudong Liu

In the direct-chill casting, the combined application of intensive melt shearing and magnetic field can significantly enhance the grain refinement of the ingot. Understanding the changes in the melt flow and temperature distribution under the influence of the combined fields is crucial for studying the mechanisms of grain refinement. COMSOL was employed to perform numerical simulations of the flow and temperature fields in the DC casting of φ300 mm 2024 aluminum alloy ingots under different intensities of melt shearing, intensities of the magnetic field, and casting speeds. The results indicate that under the combined influence of intensive melt shearing and the magnetic field, at a constant rotor rotation speed, as the current intensity of the magnetic field coil increases, the flow direction of the melt ejected from the stator gradually deflects upward, the melt flow velocity in the center of the sump slightly decreases, and the flow velocity near the edge significantly increases, leading to the reduction of the sump depth. At a constant current intensity of the magnetic field coil, the increase of the rotor rotation speed enhances the flow velocity of most of the melt within the sump and also reduces the sump depth. Furthermore, the application of the combined fields significantly enhances heat transfer at the edge of the ingot and the solidification front, which directly contributes to the reduction of the sump depth. Under the influence of the combined fields, with the casting speed increases from 65 mm/min to 75 mm/min, 85 mm/min, and 95 mm/min, the overall flow velocity distribution in the sump becomes more uniform, the overall temperature of the melt increases, the liquid sump increases from 101 mm to 122 mm, 139 mm, and 165 mm.

{"title":"Simulation study on the influence of the combined application of melt shearing and electromagnetic field on the flow and temperature fields during Direct-Chill casting of 2024 aluminum alloy","authors":"Jinchuan Wang , Yubo Zuo , Qingfeng Zhu , Rui Wang , Xianliang Guo , Xudong Liu","doi":"10.1016/j.ijheatfluidflow.2025.109782","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109782","url":null,"abstract":"<div><div>In the direct-chill casting, the combined application of intensive melt shearing and magnetic field can significantly enhance the grain refinement of the ingot. Understanding the changes in the melt flow and temperature distribution under the influence of the combined fields is crucial for studying the mechanisms of grain refinement. COMSOL was employed to perform numerical simulations of the flow and temperature fields in the DC casting of φ300 mm 2024 aluminum alloy ingots under different intensities of melt shearing, intensities of the magnetic field, and casting speeds. The results indicate that under the combined influence of intensive melt shearing and the magnetic field, at a constant rotor rotation speed, as the current intensity of the magnetic field coil increases, the flow direction of the melt ejected from the stator gradually deflects upward, the melt flow velocity in the center of the sump slightly decreases, and the flow velocity near the edge significantly increases, leading to the reduction of the sump depth. At a constant current intensity of the magnetic field coil, the increase of the rotor rotation speed enhances the flow velocity of most of the melt within the sump and also reduces the sump depth. Furthermore, the application of the combined fields significantly enhances heat transfer at the edge of the ingot and the solidification front, which directly contributes to the reduction of the sump depth. Under the influence of the combined fields, with the casting speed increases from 65 mm/min to 75 mm/min, 85 mm/min, and 95 mm/min, the overall flow velocity distribution in the sump becomes more uniform, the overall temperature of the melt increases, the liquid sump increases from 101 mm to 122 mm, 139 mm, and 165 mm.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"113 ","pages":"Article 109782"},"PeriodicalIF":2.6,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143453751","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}

引用次数: 0

Jet cooling enhancement on a heated flat surface with optimized staggered fins

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2025-02-21 DOI: 10.1016/j.ijheatfluidflow.2025.109780

Medhat M. Sorour, Wael M. El-Maghlany, Ahmed El-Shafei, Mohamed A. Alnakeeb

This paper investigates the influence of staggered fins configuration on the flow and heat transfer characteristics of a single impinging jet on a heated flat plate. A numerical study, utilizing the v²f model, was conducted across a broad range of jet Reynolds numbers (8000–40,000) and jet aspect ratios (z/d = 0.5–8). The optimal staggered fins design for maximizing heat transfer was identified through systematic variation of fin dimensions: number of rows (n), height, thickness, spacing, and pitch. The performance of the optimized staggered fins configuration was then compared to both flat plate and straight in-line fins arrangements to assess its efficacy. Additionally, an experimental facility was fabricated to validate the priority of using staggered fins in cooling the heated flat plates. The results revealed that the optimized staggered fins configuration, featuring five rows, height ratio (h/R) of 0.2, and thickness ratio (t/R) of 0.053, spacing ratio (S/R) of 0.048 and pitch ratio (p/R) of 0.30, allows better heat dissipation compared to the other arrangements. At a jet Reynolds number of 8000, a 13.87 % increase in average Nusselt number was observed compared to the flat plate, and a 9.67 % increase over straight in-line fins. This advantage becomes even more pronounced at a Reynolds number of 30,000, with enhancements of 27.36 % and 13.64 % over flat plate and straight in-line fins configurations, respectively.

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引用次数: 0

New correlation of heat transfer coefficient for saturated flow boiling in smooth helically coiled tubes

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2025-02-18 DOI: 10.1016/j.ijheatfluidflow.2025.109778

Xiande Fang , Zhiqiang He , Xinyi Wang , Yeqi Qin , Yuxiang Fang

Flow boiling heat transfer in smooth helically coiled tubes (HCTs) is widely used in many industrial sectors, such as nuclear reactors, refrigeration, and heat pump systems. It is important to predict accurately the heat transfer coefficient (HTC) of saturated flow boiling in smooth HCTs, and the prediction accuracy of the existing correlations needs to be improved. For such needs, this paper presents the work developing a new HTC correlation, with a systematic strategy combining the parameter identification, the least squares regression, the machine learning methods, the genetic algorithm, and the error distribution analysis. For developing the new HTC correlation, a database containing 1423 experimental data points of saturated flow boiling heat transfer in smooth HCTs was compiled from 16 published articles, involving four working fluids of water, R134a, R123, and R407C. It is far larger than the largest counterpart, which only contains 1035 data points from 13 published articles and involves three working fluids, and thus it has a potential to enhance greatly the applicability of the new correlation to be developed. Based on the database, 23 existing correlations were evaluated, and a new correlation was proposed. The comparison results based on the database show that the new correlation has much higher prediction accuracy than the best-performing existing one. It has a mean absolute deviation (MAD) of 20.0% and a coefficient of determination (R²) of 0.83, while the latter only has an MAD of 26.1% and a R² of 0.73.

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引用次数: 0

Investigation of blowing and suction for turbulent flow control on a transonic airfoil

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2025-02-17 DOI: 10.1016/j.ijheatfluidflow.2025.109769

A. Frede, D. Gatti

Active flow control of compressible turbulent boundary layers on airfoils via wall-normal blowing and suction is studied through a comprehensive parametric study. Wall-normal blowing or suction is applied in different positions on either the suction or pressure side of the transonic airfoil RAE2822 and its effect on the aerodynamic efficiency is investigated. The effect of the angle of attack, Mach number, control magnitude, and control position on the result of the active control are discussed. The compressible flow is simulated via Reynolds-averaged Navier–Stokes equations (RANS) with the open-source solver SU2. The inclusive drag as well as a power budget are introduced and calculated to determine the control configurations that decrease the total drag also accounting for the effort to provide and dump the control fluid. The study shows the promising potential of suction on the suction side in the transonic regime where total net drag savings of 16% were achieved in the investigated parameter range. Contrary to previous results, suction leads to a decrease in the total drag, whereas blowing leads to an increase. The appearance of non-linear effects as the shock wave, which is strongly influenced by the active control, contributes to the different performance compared to previous studies, which mostly considered incompressible flows.

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引用次数: 0