International Journal of Heat and Fluid Flow最新文献

{"title":"Analysis of energy separation mechanism of vortex tube and collaborative study with cold end aperture based on inlet nozzle diameter","authors":"Weibin Wang,&nbsp;Jianyong Wang,&nbsp;Yuanxi Wu,&nbsp;Xiaoqin Liu","doi":"10.1016/j.ijheatfluidflow.2025.109865","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109865","url":null,"abstract":"<div><div>Vortex tube, a mechanical device with simple structure designed for energy separation, is widely used in many fields. The nozzle structure of vortex tube has an important influence on its energy separation performance. At present, most studies only focus on identifying the optimal size parameters and rarely explore the influencing mechanism. This study employs numerical simulation to investigate how the vortex tube’s performance changes with variations in the inlet nozzle diameter and analyzes the internal mechanism of the above variation through flow fields. The findings indicate that reducing the inlet nozzle diameter enhances the velocity gradient and vortex intensity near the hot-end tube, promoting greater energy transfer from inner to outer fluid layers, which improves the vortex tube’s energy separation efficiency. It is also observed that the reverse flow boundary of vortex tube shrinks inward as the inlet nozzle diameter increases. Additionally, the synergistic relationship between the inlet nozzle diameter and the cold-end aperture in affecting the performance of vortex tube is investigated, which indicates as the inlet nozzle diameter increases, there are different optimal cold-end apertures, which make the vortex tube performance optimal.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"115 ","pages":"Article 109865"},"PeriodicalIF":2.6,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143874302","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":"Heat transfer and dynamic deformation in infusion bags during hot water shower sterilization: A numerically efficient two-step CFD multiphase model","authors":"Elias Hashemian Nik ,&nbsp;Thomas Schüber ,&nbsp;Gerold Macheiner ,&nbsp;Vu Hong Thang ,&nbsp;Christoph Hochenauer","doi":"10.1016/j.ijheatfluidflow.2025.109850","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109850","url":null,"abstract":"<div><div>Hot water shower sterilization is crucial for ensuring patient safety during the manufacturing of liquid pharmaceutical products. This process, when performed at lower temperature levels, can also be applied to the thermal processing of foods. The energy-intensive heating and cooling of pharmaceutical or food products by water showering lack numerically efficient multiphase models for optimization. This study introduces a numerically inexpensive two-step simulation model. In the first step, the multiphase flow and heat transfer to the product are analyzed, and a local, time-averaged surface heat transfer coefficient is calculated. This coefficient is then used as a convective boundary condition in the second step, which simulates only the internal flow of the product. A 500<!--> <!-->ml polypropylene infusion bag was used as a test product. The model considers the influence of the water film, dynamic deformation of the bag wall, conduction between the bag and the underlying hole plate, and possible condensation. The numerical model was validated with product temperature, qualitative flow regime analysis, and film thickness measurements on a lab-scale test bench. The error between the simulated and experimental product temperature was mostly within <span><math><mo>±</mo></math></span>1.0<!--> <!-->K. The critical slowest heating and cooling zones inside the bag were found to be at 15<!--> <!-->% and 85<!--> <!-->% of the bag height, respectively. Heat transfer from the bag underside and the hole plate significantly influenced the total heat transfer during the heating of the bag. The model’s high numerical efficiency enables practical application and upscaling, offering valuable insights into heat transfer mechanisms in infusion bags.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"115 ","pages":"Article 109850"},"PeriodicalIF":2.6,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868917","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":"Application of turbulent diffusivity models to point-source dispersion in outdoor and indoor flows","authors":"H.D. Lim ,&nbsp;Christina Vanderwel","doi":"10.1016/j.ijheatfluidflow.2025.109833","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109833","url":null,"abstract":"<div><div>The modelling and prediction of scalar transport in turbulent flows is crucial for many environmental and industrial flows. We discuss the key findings of our experimental campaigns which focus on two relevant applications: the scalar dispersion of a ground-level point-source in (1) a smooth-wall turbulent boundary layer flow and (2) a supply-ventilated empty room model. For flows dominated by mean advection, including many outdoor flows, we show how the Gaussian Plume Model provides a good framework to describe the mean scalar field and discuss its limitations in assuming an isotropic and homogeneous turbulent diffusivity. For indoor flows, we explore the balance of the advective and turbulent fluxes and their dependence on the near-source flow field. We use our improved understanding on the scalar transport mechanism in these applications to assess the application of the Eddy Diffusion Model to predict indoor scalar dispersion, and highlight the importance of carefully defining what the turbulent diffusivity coefficient encompasses in different approaches.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"115 ","pages":"Article 109833"},"PeriodicalIF":2.6,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868915","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":"Numerical heat transfer enhancement study on phase change thermal energy storage exchanger with perforated fins","authors":"Rui Zhu ,&nbsp;Gaosheng Wei ,&nbsp;Meiyang Xu ,&nbsp;Gang Wang","doi":"10.1016/j.ijheatfluidflow.2025.109861","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109861","url":null,"abstract":"<div><div>Addition of fins is one of effective methods for heat transfer enhancement in heat exchangers. However, adding fins inside the heat exchanger also impedes fluid flow, which in turn affects natural convection heat transfer, especially for phase change heat storage exchangers. This study involves perforating the internal fins of the phase change thermal storage heat exchanger to reduce the obstruction of fins to the natural convection of phase change materials. The computations, carried out using the melting and solidification model for three-dimensional unsteady simulations. In the numerical simulation study on heat transfer enhancement, eight longitudinal perforated fins are imbedded uniformly and non-uniformly in a tubular phase change heat exchanger and their heat transfer enhancement performance are carefully examined and compared. The perforation diameter and hole distributions are evaluated by analyzing liquid phase ratio of the phase change material and the total melting time, thereby maximizing the combined enhancement effect of fin conduction and natural convection heat transfer in the liquid. The results indicate that fin perforation can effectively balance the thermal conductivity of the fins with the natural convection of the phase change materials when combined with full-scale fins. The optimal heat transfer enhancement occurs when the distance between the two holes and the inner tube is 6 mm and 15 mm, respectively, with an axial hole spacing of less than 10 mm and a hole diameter of 0.86 mm. On this basis, the use of perforated non-uniform fins significantly reduced the total melting time of the phase change material by 45.3 % compared to fins without perforating, thereby improving the efficiency of the phase change heat exchanger.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"115 ","pages":"Article 109861"},"PeriodicalIF":2.6,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868916","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":"Study on noise reduction performance of two-dimensional pillar shapes and porous medium","authors":"Fangying Lou ,&nbsp;Xinbiao Xiao ,&nbsp;Zongfa Zhang ,&nbsp;Jian Han ,&nbsp;Xin Zhao ,&nbsp;Dekuo Pan","doi":"10.1016/j.ijheatfluidflow.2025.109855","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109855","url":null,"abstract":"<div><div>To study the effects of two-dimensional (2D) pillar shapes and the parameters of porous materials on flow field characteristics and aerodynamic noise, this study employs the Improved Delayed Detached Eddy Simulation (IDDES) method combined with the Ffowcs Williams-Hawkins (FW-H) equation to numerically simulate the flow field and aerodynamic noise of the pillars with variable cross-sections (cylindrical pillar, elliptical pillar, rounded square pillar and square pillar) and pillars covering with porous medium. The parameters of the porous medium under investigation include: porosity (<span><math><mi>ϕ</mi></math></span>), particle diameter (<em>dp</em>) and medium layer thickness (<em>h</em>). Proper Orthogonal Decomposition (POD) was utilized to perform reduced-order analysis of unsteady flow in the wake region, revealing the physical significance of POD modes of different pillars in wake evolution. The results indicate that the elliptical pillar exhibits the best performance in noise reduction, with its design allowing for a maximum reduction of 7 dBA in the far-field overall sound pressure level, among the four types of pillars with variable cross-sections. And the three types of porous medium parameters significantly affect the noise reduction performance of the pillar. Among them, the pillar with parameter combination of <em>dp</em> = 500 μm, <span><math><mi>ϕ</mi></math></span>=0.97, and <em>h</em> = 0.25 <em>D</em> exhibit superior noise reduction effects, with a maximum reduction of 10.2 dBA in the far-field overall sound pressure level. Porous medium layer with reasonable parameters can significantly delay boundary layer separation, extend the stable region of the shear layer, and attenuate velocity and vorticity magnitudes in the wake region, thus suppressing turbulence fluctuations and aerodynamic noise.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"115 ","pages":"Article 109855"},"PeriodicalIF":2.6,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143859644","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":"Research on damaged unit detection of lithium battery thermal management system","authors":"Yi-Long Lou ,&nbsp;Kang Zhang ,&nbsp;Xiao-Hui Feng ,&nbsp;Jian-Wu Qu ,&nbsp;Zhen-Zhe Li ,&nbsp;Mei-Ling Zhang","doi":"10.1016/j.ijheatfluidflow.2025.109857","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109857","url":null,"abstract":"<div><div>Currently, the electric car sector is experiencing significant growth and is widely popular among the consumers due to its utilization of clean energy and little impact on the environment. The battery of electric vehicles is a crucial constraint on the advancement of the electric vehicles, with its temperature being the primary component that greatly affects the battery’s performance. This article examines the structural parameters of lithium battery packs in order to enhance their durability. By utilizing a sample optimization method, the ideal structural parameters are determined to ensure an improved cooling effect. Subsequently, three types of battery damage were simulated using different heat generation rates. By arranging the temperature sensors and analyzing the feedback values of the sensors under three types of damaged conditions, a rule that determining the damaged location and damaged degree of a certain battery in the battery pack can be obtained by using fewer temperature sensors. Finally, by fitting the feedback values as a quadratic function, an equation accurately determining the degree of damage is obtained. The damaged unit detection scheme proposed in this article can be widely applied to improve the safety of battery systems and reduce the occurrence of hazards such as fire and explosion caused by overheating of the batteries.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"115 ","pages":"Article 109857"},"PeriodicalIF":2.6,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143859595","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":"Comparison of sub-convective pressure fluctuations over a smooth and rough wall","authors":"Shishir Damani,&nbsp;Eric Totten,&nbsp;Humza Butt,&nbsp;Bhavika Sharma,&nbsp;William J. Devenport,&nbsp;K. Todd Lowe","doi":"10.1016/j.ijheatfluidflow.2025.109835","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109835","url":null,"abstract":"<div><div>Sub-convective wall pressure fluctuations are compared for a smooth and rough surface with homogeneously distributed roughness elements. Limitations in measurement techniques make it challenging to measure the sub-convective pressure spectrum over smooth surfaces, and there are no general techniques for rough walls. The study presented here uses a recently developed approach to accurately measure the sub-convective pressure fluctuations, particularly at low-wavenumbers for a single flow condition for two surfaces. Correlations between different sensors suggest smaller scales in rough walls than in smooth walls. A significant expansion of the convective ridge is noticed. Normalizations of the wavenumber-frequency spectrum as <span><math><mrow><msub><mrow><mi>ϕ</mi></mrow><mrow><mi>p</mi><mi>p</mi></mrow></msub><mrow><mo>(</mo><msub><mrow><mi>k</mi></mrow><mrow><mn>1</mn></mrow></msub><msup><mrow><mi>δ</mi></mrow><mrow><mo>∗</mo></mrow></msup><mo>,</mo><mi>ω</mi><msup><mrow><mi>δ</mi></mrow><mrow><mo>∗</mo></mrow></msup><mo>/</mo><msub><mrow><mi>U</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>)</mo></mrow><msub><mrow><mi>U</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>/</mo><msubsup><mrow><mi>τ</mi></mrow><mrow><mi>w</mi></mrow><mrow><mn>2</mn></mrow></msubsup><msup><mrow><mi>δ</mi></mrow><mrow><msup><mrow><mo>∗</mo></mrow><mrow><mn>2</mn></mrow></msup></mrow></msup></mrow></math></span> shows a near-exact collapse at the convective peak. The normalized spectral levels show a difference of about 25 dB in the sub-convective domain due to rough wall convective ridge behavior. The absolute sub-convective pressure spectrum levels relative to 20 <span><math><mi>μ</mi></math></span>Pa are about 30 dB below the convective pressure fluctuations for smooth walls. Rough wall measurements show absolute levels 15–20 dB higher than the smooth wall. A wavenumber-white behavior is observed at higher frequencies for smooth and rough walls. Both smooth and rough walls show a convection velocity dependent on frequency. The rough wall convective ridge width shows a frequency dependency, whereas the smooth wall convective ridge width collapses at all frequencies.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"115 ","pages":"Article 109835"},"PeriodicalIF":2.6,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143851483","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":"Predicting the global drag of turbulent channel flow over roughness strips","authors":"Jonathan Neuhauser,&nbsp;Carola Schmidt,&nbsp;Davide Gatti,&nbsp;Bettina Frohnapfel","doi":"10.1016/j.ijheatfluidflow.2025.109848","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109848","url":null,"abstract":"<div><div>Predicting the global drag of heterogeneous rough surfaces remains one of the great challenges in roughness research (Chung et al., 2021). In the limit where patch sizes are much larger than the boundary layer thickness, predictive formulas can be derived under the assumption that the flow is in local equilibrium with the surface properties (Neuhauser et al., 2022, Hutchins et al., 2023). The present work extends this concept to predict the drag behavior of turbulent channel flows over surfaces with spanwise heterogeneous roughness properties which vary over length scales comparable to the boundary layer thickness. The drag predictions are compared with high-fidelity measurements obtained in an air channel flow facility (Frohnapfel et al., 2024). As an outlook to future work, it is discussed how heat transfer over rough surface strips can be modeled under the local equilibrium assumption.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"115 ","pages":"Article 109848"},"PeriodicalIF":2.6,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143844417","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":"Heat transfer and flow characteristics of supercritical carbon dioxide in nanochannels","authors":"Chenyang Sun,&nbsp;Wenke Zhao,&nbsp;Yaning Zhang,&nbsp;Bingxi Li","doi":"10.1016/j.ijheatfluidflow.2025.109852","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109852","url":null,"abstract":"<div><div>As the integration density of micro-nano electronic devices continues to increase, utilizing nanochannels for thermal management has emerged as a promising approach. Supercritical carbon dioxide (scCO₂) serves as an efficient coolant that can readily achieve a supercritical state within nanochannels, due to confinement effects and interactions with the channel walls. However, its behavior and applications in nanochannels have been less extensively explored. In this study, nonequilibrium molecular dynamics simulations were used to investigate how interface wettability, wall temperature, and applied force affect the heat transfer and flow characteristics of scCO₂ in nanochannels. The results indicate that interface wettability significantly affects the heat transfer characteristics and slip length at the wall-fluid interface. Under strong wettability, the interfacial thermal resistance is two orders of magnitude higher than those under weak wettability. Specifically, the interfacial thermal resistance is 3.01 × 10^-10 (K∙m²)/W under strong wettability and 5.22 × 10^-8 (K∙m²)/W under weak wettability. Similarly, the slip length is −0.204 nm under strong wettability and 0.755 nm under weak wettability. While the wall temperature and applied force exhibit minimal impact on interfacial heat transfer, they significantly influence the slip length. At 700 K, the slip length is 0.106 nm, whereas at 400 K, it decreases to −0.113 nm. Furthermore, when the applied force is increased fivefold, the slip length increases from −0.041 nm to 0.067 nm. Finally, the vibrational density of states, liquid structuring and density depletion length were analyzed to clarify the mechanisms governing interface heat transfer and flow characteristics.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"115 ","pages":"Article 109852"},"PeriodicalIF":2.6,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143844416","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":"Numerical study on ash accumulation and heat transfer characteristics in flue gas side of tubular air preheater","authors":"Jiajie Zhang ,&nbsp;Yifan Feng ,&nbsp;Rui Li ,&nbsp;Xinlong Wang ,&nbsp;Jianfei Wang ,&nbsp;Yong Li ,&nbsp;Suxia Ma","doi":"10.1016/j.ijheatfluidflow.2025.109851","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109851","url":null,"abstract":"<div><div>Ash accumulation in the tubular air preheater is one of the key problems affecting its safe and efficient operation. To reveal its mechanism, a numerical simulation based on the Euler-Lagrange method is conducted in this paper. The deposition and removal of ash particles on the finned tubes are described by using the critical velocity model and critical wall shear velocity model, respectively, the influence of ash accumulation growth on heat transfer is also considered by establishing an equivalent thermal resistance model. The results show that a backflow is occurred at the leeward area of the tube with the formation of trapped vortex. The ash accumulation basically occurs at the windward side of the fin and reaches a peak at the tube of Column Ⅱ under the joint action of the scour of incoming gas and the entrainment of trapped vortex. The larger gas velocity may enlarge the kinetic energy of ash particle, thence alleviates the ash accumulation mass and improves the total heat transfer coefficient of preheater. The increase of particle diameter may reduce the followability of particle with gas, which has a greater effect on the ash accumulation at the leeward side of the fin relative to the windward side. The larger longitudinal spacing between tube bundles makes the velocity distribution more evenly, which reduces the ash accumulation mass and enhances the total heat transfer coefficient. The increase of transverse spacing enlarges the particle concentration near the tube bundles, and then increases the ash accumulation mass, that at the leeward side of fin reaches a peak when <em>P</em>_L = 80 mm.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"115 ","pages":"Article 109851"},"PeriodicalIF":2.6,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143844415","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}