International Journal of Heat and Fluid Flow最新文献_第8页

A comprehensive review of nucleate boiling fundamentals applied to thin film annular flow 核沸腾基本原理在薄膜环流中的应用综述

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2025-12-14 DOI: 10.1016/j.ijheatfluidflow.2025.110199

Joseph Farrell , Evan T. Hurlburt , Arganthaël Berson , Allison Mahvi

Nucleate boiling in thin film annular flow is a complex phenomenon influenced by a variety of heat transfer mechanisms. While the fundamentals are rooted in the comparatively well-understood fields of pool and flow boiling, thin film flow boiling introduces additional challenges that make the heat transfer behavior hard to predict. Specifically, the relative importance of the heat transfer mechanisms controlling nucleate boiling in thin annular films and their roles in flow regime transitions remains inadequately understood. In light of this, the foundational aspects of nucleate boiling and the relationship between flow parameters – such as liquid film thickness, system pressure, surface tension, channel geometry, mass flow rate, and applied heat flux – and the intensity of nucleate boiling in thin annular films are analyzed. The importance of these parameters is demonstrated through the presentation of multiple correlations, with a critical examination of the limitations inherent in correlation-based modeling. Additionally, recent research has identified disturbance waves as a significant factor in enhancing bubble nucleation, yet the underlying mechanisms driving this phenomenon remain undefined. Therefore, the insights and deficiencies of three theories seeking to explain wave-based nucleation are extensively considered. This research aims to introduce and categorize the wide breadth of literature regarding thin film annular flow nucleate boiling to identify gaps in understanding and facilitate future physics-based modeling efforts.

薄膜环流中的核沸腾是一个受多种传热机制影响的复杂现象。虽然基本原理植根于相对较好理解的池沸腾和流动沸腾领域，但薄膜流动沸腾引入了额外的挑战，使传热行为难以预测。具体来说，控制环状薄膜中核沸腾的传热机制的相对重要性及其在流态转变中的作用仍然没有得到充分的认识。在此基础上，分析了液膜厚度、系统压力、表面张力、通道几何形状、质量流量、外加热流密度等流动参数与薄环形膜中成核沸腾强度的关系。这些参数的重要性通过多个相关性的呈现来证明，并对基于相关性的建模固有的局限性进行了严格的检查。此外，最近的研究已经确定扰动波是增强气泡成核的重要因素，但驱动这一现象的潜在机制仍未明确。因此，寻求解释波基成核的三个理论的见解和不足被广泛考虑。本研究旨在介绍和分类关于薄膜环流核沸腾的广泛文献，以确定理解上的差距，并促进未来基于物理的建模工作。

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引用次数: 0

An autoencoder-based bi-fidelity method utilising frozen latent spaces. Application to flow past a confined cylinder 一种基于自编码器的双保真度方法，利用冻结隐空间。用于流过密闭圆筒

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2025-12-12 DOI: 10.1016/j.ijheatfluidflow.2025.110192

W. Lu , W.K. Lam , T. Zahtila

This study presents a simple autoencoder-based bi-fidelity method, where the latent space is constrained to be invariant between both low- and high-fidelity datasets. The method is applied to the flow past a cylinder confined in a duct, where model fidelity is governed by computational model resolution. Significant cost savings are observed without significant compromise to approximation accuracy. The influence of several hyperparameters are considered including: latent space dimension, sample number and distribution. A method of generating synthetic solutions is also explored. This is done by performing regression on the common latent space of low- and high-fidelity models, which is then passed through the high-fidelity decoder. As a large number of samples are available from the low-fidelity model, significant improvements are observed compared with the traditional method of interpolating only high-fidelity data.

本研究提出了一种简单的基于自编码器的双保真度方法，其中潜在空间在低保真度和高保真度数据集之间被约束为不变。该方法适用于流通过一个圆柱体限制在一个管道，其中模型保真度是由计算模型的分辨率。在不影响近似精度的情况下，显著节省了成本。考虑了几个超参数的影响，包括潜在空间维数、样本数量和分布。本文还探讨了一种生成合成解的方法。这是通过对低保真度和高保真度模型的共同潜在空间执行回归来完成的，然后将其通过高保真度解码器。由于低保真度模型中有大量的样本，与传统的只插值高保真度数据的方法相比，有了显著的改进。

引用次数: 0

Preliminary study on the dynamic equilibrium process of supercritical region CO2 fluid by phase field method 用相场法初步研究超临界区CO2流体的动态平衡过程

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2025-12-11 DOI: 10.1016/j.ijheatfluidflow.2025.110189

Huan Liu , Pavel Skripov , Lin Chen

The supercritical fluid region is generally considered a complex phase region, which has a lot on the thermodynamic transitions and fluid transport behaviors of a system. The present study introduces a phase-field method using density as the order parameter, which is combined with a free energy minimization technique to predict the dynamic responses of supercritical CO₂ under parameter equilibrium procedures. During this phase, field simulation analysis, cases from the close-to-critical region, liquid region, and low-density fluid region have been examined, which procedures then show a system equilibrium stage from ‘quasi-uniform’ state to an ‘overall equilibrium’ state. The simulation process follows a continuous and gradual change in macroscopic properties rather than the abrupt transition observed in the conventional phase change process. By statistically tracking the temporal evolution of ‘pseudo-liquid regions’, the local non-uniformities emergence process during the formation of supercritical phases has been revealed, which in turn gives the dynamic development of spatial heterogeneity. The extrema of density fluctuations form ridge lines near the pseudo-critical line, with a maximum spatial fluctuation error of 0.06% compared to the pseudo-critical line. The boundary identified with intense density fluctuations resembles the dynamic transition across the pseudo-critical triangle.

超临界流体区通常被认为是一个复杂的相区，它对系统的热力学转变和流体输运行为有很大的影响。本文介绍了一种以密度为序参量的相场法，结合自由能最小化技术来预测超临界CO2在参数平衡过程中的动态响应。在此阶段，现场模拟分析了近临界区域、液体区域和低密度流体区域的情况，这些过程显示了系统从“准均匀”状态到“整体平衡”状态的平衡阶段。模拟过程遵循宏观性质的连续渐进变化，而不是传统相变过程中观察到的突然转变。通过统计跟踪“伪液体区域”的时间演变，揭示了超临界相形成过程中局部非均匀性的出现过程，从而给出了空间异质性的动态发展。密度波动极值在拟临界线附近形成脊线，与拟临界线相比，最大空间波动误差为0.06%。具有强烈密度波动的边界类似于跨越伪临界三角形的动态过渡。

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引用次数: 0

Mathematical modelling and heat-mass transport analysis of a bioconvective Casson hybrid nanofluid in a stenosed artery 狭窄动脉中生物对流卡森混合纳米流体的数学建模和热质传递分析

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2025-12-10 DOI: 10.1016/j.ijheatfluidflow.2025.110190

Anthuvan Ezhilarasi P., Dhivya Mohanavel

Arterial stenosis causes the arteries to narrow, a change that can significantly impact blood flow. Identifying the conditions related to arterial blockage is crucial for prompt diagnosis and treatment. Keeping this fact in mind, the purpose of this study is to analyse the heat and mass transfer properties of a Casson hybrid blood flow in a constricted artery inhabited by oxytactic microorganisms, and also by employing the Arrhenius energy. The mathematical assessment of copper and titanium oxide in the stenosis region, where blood circulates, considers temperature-dependent viscosity and thermal conductivity. The hybrid (Cu/TiO

_{2}

) nanoparticles used in the bloodstream synergise to enhance heat and mass transfer, offers antithrombotic and antimicrobial benefits which promote better vascular health and prevent infection. The governing coupled partial differential equations are converted into a system of nonlinear ordinary differential equations via the similarity transformation technique, and the resulting ODE is then numerically solved using the MATLAB solver. The influences of various factors, including variable viscosity, variable thermal conductivity, activation energy, chemical reaction, bioconvection Schmidt number, and Peclet number, have been examined in equations for velocity, temperature, concentration, and microorganisms. The primary findings indicate that varying the viscosity parameter slows the flow rate, whereas raising the values of thermal conductivity parameter makes heat transmission more reliable. Additionally, the reduction in motile density profiles was attributed to both Lewis number and bioconvection Schmidt number. Furthermore, this study was compared to previous results, showing a high degree of correspondence. The sensitivity analysis used in this model examines the impact of different factors on the effectiveness of convective and diffusive transport processes in mass transfer. This research can improve arterial disease diagnostic techniques by simulating intricate blood flow scenarios.

动脉狭窄导致动脉狭窄，这种变化会显著影响血液流动。确定与动脉阻塞相关的条件对于及时诊断和治疗至关重要。考虑到这一事实，本研究的目的是分析卡森杂交血液在有氧合微生物居住的收缩动脉中的传热和传质特性，并利用阿伦尼乌斯能量。在血液循环的狭窄区域，铜和氧化钛的数学评估考虑了温度依赖性粘度和导热性。混合（Cu/TiO2）纳米颗粒用于血液协同增强热量和质量传递，提供抗血栓和抗菌的好处，促进更好的血管健康和预防感染。利用相似变换技术将控制耦合偏微分方程转化为非线性常微分方程组，利用MATLAB求解器对得到的微分方程进行数值求解。各种因素的影响，包括变粘度、变导热系数、活化能、化学反应、生物对流施密特数和佩克莱数，已经在速度、温度、浓度和微生物的方程中进行了检验。初步研究结果表明，改变粘度参数会减慢流速，而提高导热系数参数使传热更可靠。此外，运动密度曲线的减小归因于Lewis数和生物对流Schmidt数。此外，本研究与以往的结果进行了比较，显示出高度的一致性。该模型中使用的敏感性分析考察了不同因素对传质过程中对流和扩散传递过程有效性的影响。这项研究可以通过模拟复杂的血流场景来改善动脉疾病的诊断技术。

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引用次数: 0

Impact of cylinder diameter and spacing on fluid flow, forces, and heat transfer in tandem cylinder configuration 圆柱直径和间距对串联式圆柱结构中流体流动、力和传热的影响

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2025-12-10 DOI: 10.1016/j.ijheatfluidflow.2025.110178

Md. Mahbub Alam , Zia Ullah , Hongjun Zhu , Chunning Ji , Md. Islam , Mostafa Zeinoddini

This study numerically investigates the fluid flow, aerodynamic forces, and heat transfer characteristics around a circular cylinder (diameter D) positioned in the wake of another cylinder (diameter d), with varying diameter ratios d/D (= 0.4, 0.6, 0.8, and 1.0) and inter-cylinder spacing ratios L* (= L/D = 1.2 –5.0). Significant effects of d/D and L* are identified on forces, heat transfer, and fluid dynamics at Re_D = 200. For a given L*, time-mean drag, fluctuating lift and drag, and Nusselt number all are generally smaller for larger d/D, with the time-mean drag force even becoming negative for d/D = 1.0. In the reattachment flow regime, the time-mean drag and Nusselt number decrease with increasing L* for smaller d/D = 0.4 and 0.6 but increase for larger d/D = 0.8 and 1.0. In the coshedding flow regime, the Nusselt number and forces increase with L*, regardless of d/D. The critical L* separating the reattachment and coshedding flows increases with increasing d/D from 0.4 to 0.8 before declining from d/D = 0.8 to 1.0. Streamwise velocity fields and local Nusselt number distributions on the cylinder surface are analyzed to explain the observed heat transfer phenomena. Local heat transfer is maximal on the front surface of the cylinder, corresponding to the inflection point on the near-surface velocity profile.

本文通过数值模拟研究了不同直径比D /D（= 0.4、0.6、0.8和1.0）和缸间间距比L* (= L/D = 1.2 -5.0)下，一个圆柱体（直径D）与另一个圆柱体（直径D）的尾迹之间的流体流动、气动力和传热特性。在ReD = 200时，确定了d/ d和L*对力、传热和流体动力学的显著影响。对于给定的L*，当d/ d较大时，时间平均阻力、波动升力和阻力以及努塞尔数一般都较小，当d/ d = 1.0时，时间平均阻力甚至变为负值。当d/ d = 0.4和0.6时，时间平均阻力和Nusselt数随L*的增大而减小，当d/ d = 0.8和1.0时，时间平均阻力和Nusselt数随L*的增大而增大。在共脱落流态中，努塞尔数和力随L*的增加而增加，与d/ d无关。分离重附流和共脱落流的临界L*随着d/ d的增加从0.4增大到0.8，然后从d/ d = 0.8减小到1.0。分析了圆柱表面的流向速度场和局部努塞尔数分布来解释观察到的换热现象。局部换热在柱体前表面最大，与近表面速度剖面的拐点相对应。

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引用次数: 0

Design and performance optimization of liquid immersion cooling system for prismatic lithium-ion battery modules 棱镜型锂离子电池模块液浸冷却系统设计及性能优化

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2025-12-08 DOI: 10.1016/j.ijheatfluidflow.2025.110181

Luyao Zhao, Jiafeng Wang, Minxue Zheng, Mingyi Chen

Optimal thermal regulation in battery modules is critical for maintaining the efficient and reliable operation of battery packs. This study designed an active immersion cooling system for prismatic lithium-ion battery modules, demonstrating maximum temperature reductions of 34 % and 47.7 % relative to static submersion cooling and free convection methods, respectively. The impacts of coolant flow rate, flow direction, and module arrangement patterns on forced-flow immersion cooling performance were numerically investigated. Results indicate that parallel battery arrangements show superior cooling performance compared to staggered configurations. Among the five flow patterns (top to bottom, bottom to top, top to top, bottom to bottom, and center to center), the top to bottom layout exhibits the optimal cooling efficiency. As the inlet flow rate increases, both the maximum battery temperature and the temperature difference across the battery pack first drop sharply and then slowly after the flow rate reaches 0.023 kg/s. Power consumption demonstrates a positive relationship with inlet velocity, whereas the cooling index shows an inverse relationship. As the horizontal spacing between batteries varies from 1 to 6 mm, the maximum temperature of the battery and temperature difference show a “U” shaped trend, the power consumption decreases monotonically, while the cooling index shows a “И” shaped variation trend. Similarly, with the increase of longitudinal distance between batteries, Both the peak battery temperature and temperature differential present a “U” shaped variation trend, and the power dissipation decreases monotonically. Conversely, the cooling index increases monotonously. Finally, a 4-mm horizontal and 5-mm longitudinal spacing were identified as the optimal configuration. This study addressed both operational safety and thermal management efficiency for prismatic lithium-ion batteries, and established design guidelines for high-performance immersion cooling systems.

电池模块的最佳热调节对于保持电池组的高效可靠运行至关重要。该研究为棱柱形锂离子电池模块设计了一种主动浸没冷却系统，与静态浸没冷却和自由对流冷却方法相比，最大温度分别降低了34%和47.7%。研究了冷却剂流量、流动方向和模块布置方式对强制浸没冷却性能的影响。结果表明，与交错配置相比，并联电池配置具有更好的冷却性能。在5种流动模式（从上到下、从下到上、从上到上、从下到下、从中心到中心）中，从上到下的布局具有最佳的冷却效率。随着进口流量的增加，在流量达到0.023 kg/s后，电池最高温度和电池组温差均先急剧下降，然后缓慢下降。功率消耗与进口速度呈正相关，而冷却指数呈反比关系。当电池水平间距在1 ~ 6mm范围内变化时，电池最高温度和温差呈“U”型变化趋势，功耗单调下降，冷却指数呈“И”型变化趋势。同样，随着电池间纵向距离的增加，电池峰值温度和温差均呈“U”型变化趋势，且功耗单调减小。反之，冷却指数单调增加。最后，确定水平间距为4 mm，纵向间距为5 mm为最优配置。该研究解决了棱柱形锂离子电池的操作安全性和热管理效率，并建立了高性能浸入式冷却系统的设计指南。

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引用次数: 0

Comparative study on heat extraction performance and economic feasibility between medium-deep coaxial and U-type ground heat exchangers 中深同轴与u型地热交换器排热性能及经济可行性对比研究

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2025-12-06 DOI: 10.1016/j.ijheatfluidflow.2025.110170

Pengtao Wang , Rui Liang , Shimin Wang , Junyu Feng , Jie Zhang , Shengshan Bi

This study utilizes a geothermal heating project located in Xi’an as a case study, developing full-scale numerical models for medium-deep coaxial borehole heat exchangers (DCBHE) and medium-deep U-type borehole heat exchangers (DUBHE) at equivalent depths. Through extensive heat transfer simulations conducted over five cycles, the research provides a comprehensive comparison of the heat extraction efficiency and economic viability of the two types of ground heat exchangers. This comparison employs a ratio method that accounts for pump energy losses, the levelized cost of heat (LCOH), and net present value (NPV) metrics. The findings indicate that the heat exchange per unit length for DCBHE and DUBHE ranges from 123.1 to 149.5 W/m and 93.9 to 170.71 W/m, respectively, with a critical flow rate of 7.21 kg/s. When incorporating pump power consumption, the critical flow rate is determined to be 6.62 kg/s, which corresponds to a comprehensive heat exchange per unit length of 127.7 W/m. Beyond this flow rate, the comprehensive heat transfer performance of DUBHE surpasses that of DCBHE. Therefore, this study divides the heat extraction zones into low-flow zones and high-flow zones based on the critical flow rate of 6.62 kg/s, providing a qualitative identification basis for selecting appropriate flow rate conditions for different types of heat exchangers. The economic analysis reveals that at the critical flow rate, the cost per unit of heat extraction for DCBHE exceeds that of DUBHE, and as the heat extraction duration increases, the NPV of DUBHE becomes more favorable compared to DCBHE. Consequently, DUBHE is determined to be more economically viable than DCBHE.

本研究以西安某地热供热项目为例，建立了等效深度的中深同轴井眼热交换器（DCBHE）和中深u型井眼热交换器（DUBHE）全尺寸数值模型。通过对5个循环进行的广泛的传热模拟，研究提供了两种类型的地面热交换器的热提取效率和经济可行性的综合比较。这种比较采用了一种比率法，该方法考虑了泵的能量损失、热量平准化成本（LCOH）和净现值（NPV）指标。结果表明：DCBHE和DUBHE的单位长度换热范围分别为123.1 ~ 149.5 W/m和93.9 ~ 170.71 W/m，临界流量为7.21 kg/s；考虑泵功率消耗，确定临界流量为6.62 kg/s，单位长度综合换热127.7 W/m。在此流量之外，DUBHE的综合换热性能优于DCBHE。因此，本研究以6.62 kg/s的临界流量为基础，将抽热区划分为低流量区和高流量区，为不同类型换热器选择合适的流量条件提供定性识别依据。经济分析表明，在临界流量下，DCBHE的单位抽热成本高于DUBHE，且随着抽热时间的增加，DUBHE的净现值优于DCBHE。因此，DUBHE在经济上比DCBHE更可行。

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引用次数: 0

Experimental and numerical investigation of fast control surface deflections 快速控制曲面挠度的实验与数值研究

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2025-12-05 DOI: 10.1016/j.ijheatfluidflow.2025.110177

Ruben B. Seidler , Reinhard Geisler , Andreas Schröder , Jochen Wild

The development of load alleviation for an aircraft requires an accurate and efficient prediction of gust and maneuver loads. In the design of an aircraft the prediction of these unsteady loads has become crucial for the ideal alleviation of gust loads. A database for unsteady aerodynamic responses is however very cost expensive and time consuming to generate, in an experiment and with numerical simulations. An efficient tool for the computation of aerodynamic responses is the linear frequency domain solver, which allows the prediction of amplitude and phase shift of any periodic oscillation of body or flow in the frequency domain. The unsteady response allows a fast and efficient prediction for any arbitrary unsteady change of in example a control surface deflection or a gust speed. The validation of the linear frequency domain solver for unsteady aerodynamics is crucial, so that its prediction quality is ensured. A wind tunnel experiment was set up, which focused on fast control surface deflections and analyzed the capabilities and accuracy of the method. The experiment was accompanied by two- and three-dimensional URANS simulations, which allow a more detailed comparison and help to increase the understanding of the flow physics. For higher frequencies of the control surface oscillation, the adjusting position of the stagnation point on the leading edge lags behind the actual control surface position as if it were in a quasi-steady state. This leads to a phase lag between motion and resulting force and a lower lift response amplitude.

飞机减载的发展需要对阵风和机动载荷进行准确有效的预测。在飞机设计中，对这些非定常载荷的预测对于理想地减轻阵风载荷至关重要。然而，在实验和数值模拟中，非定常气动响应数据库的生成是非常昂贵和耗时的。线性频域求解器是计算气动响应的有效工具，它可以在频域内预测物体或流动的任何周期振荡的幅值和相移。非定常响应允许对任意非定常变化进行快速有效的预测，例如控制面偏转或阵风速度。非定常空气动力学线性频域解算器的验证是保证其预测质量的关键。以快速控制曲面偏转为研究对象，建立了风洞实验，分析了该方法的性能和精度。该实验同时进行了二维和三维URANS模拟，可以进行更详细的比较，并有助于增加对流动物理的理解。当控制面振荡频率较高时，前缘驻点的调节位置滞后于实际控制面位置，仿佛处于准稳态。这导致运动和产生的力之间的相位滞后和较低的升力响应幅度。

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引用次数: 0

Flow regime identification in a dual impeller gas-liquid stirred tank reactor using time-series analysis of radioactive particle tracking data 利用放射性粒子跟踪数据的时间序列分析识别双叶轮气液搅拌槽式反应器的流态

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2025-12-05 DOI: 10.1016/j.ijheatfluidflow.2025.110167

Roushni Kumari , Raghvendra Gupta , Jayashree Biswal , Miryan C. Cassanello , Rajesh Kumar Upadhyay

Accurate characterization of flow regimes in gas–liquid stirred tank reactors (STRs) is critical for the design, scale-up, and optimization of multiphase mixing systems. This study investigates three-dimensional liquid flow fields in a lab-scale dual impeller gas–liquid STR (T = 0.19 m), equipped with radial and mixed flow impellers. A non-invasive Radioactive Particle Tracking (RPT) technique was used to capture detailed flow behavior under varying operating conditions. Velocity vector plots, mean liquid velocity, and turbulent kinetic energy (TKE) profiles were analyzed to evaluate the hydrodynamic influence of impeller configuration and impeller spacing. To further understand the chaotic nature of the flow, time-series data from the tracked particle were processed, using Kolmogorov entropy, following the approach of Nedeltchev et al. (2003) for bubble columns. This entropy-based method enabled identification of flow regimes across different impeller speeds and superficial gas velocities, and impeller-to-impeller spacing to impeller diameter ratio (S/D). Additionally, the individual contributions of the lower and upper impellers to local Kolmogorov entropy were assessed, revealing their distinct roles in flow and bubble dispersion. The integration of RPT measurements with Kolmogorov entropy analysis provides a robust framework for understanding complex flow patterns and enhancing hydrodynamic design in dual impeller STRs.

准确表征气液搅拌槽式反应器（STRs）的流动状态对于多相混合系统的设计、放大和优化至关重要。本文研究了一个实验室规模的双叶轮气液STR （T = 0.19 m）的三维液体流场，该STR配备径向和混合流叶轮。一种非侵入性放射性粒子跟踪（RPT）技术用于捕获不同操作条件下的详细流动行为。通过对速度矢量图、平均液体速度和湍流动能（TKE）分布曲线的分析，评估了叶轮构型和叶轮间距对流体动力的影响。为了进一步了解流动的混沌性质，利用Kolmogorov熵，按照Nedeltchev等人（2003）对气泡柱的方法，对来自跟踪粒子的时间序列数据进行处理。这种基于熵的方法可以识别不同叶轮转速和表面气体速度下的流动状态，以及叶轮与叶轮之间的间距与叶轮直径比（S/D）。此外，还评估了上下叶轮对局部Kolmogorov熵的贡献，揭示了它们在流动和气泡分散中的不同作用。RPT测量与Kolmogorov熵分析的集成为理解复杂的流动模式和加强双叶轮str的流体动力设计提供了一个强大的框架。

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引用次数: 0

Analyzing the impact of various heating element cross-sections on the melting progression of phase change material 分析了不同加热元件截面对相变材料熔化过程的影响

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2025-12-05 DOI: 10.1016/j.ijheatfluidflow.2025.110163

Ali Radwan , Essam M. Abo-Zahhad , Ahmed Saad Soliman

Storing thermal energy in horizontally aligned cavities often suffers from limited energy storage capacity for a given thermal charging period. To address this limitation, this study aims to computationally investigate the impact of the shape and position of the heating element on the melting progression of phase change material (PCM) contained in a cylindrical cavity. The analyzed cases include concentric triangular, shifted triangular, concentric square, shifted square, concentric elliptical, and shifted elliptical cross-sections, and these are evaluated against a baseline case employing a conventional circular heating element. The results demonstrate that a shifted elliptical cross-section significantly enhances PCM melting in horizontally aligned thermal storage units. The melting time is reduced by approximately 52.8% when the standard circular heating element is replaced with a shifted elliptical heating element of equal cross-sectional area. To further investigate this improvement, the simulations are performed for various aspect ratios and shift ratios of the elliptical heating element. The findings show that a prolate elliptical shape shifted toward the bottom of the cylinder provides the best performance. The optimized elliptical heating element reduces the complete melting time by 76.9 % compared to the conventional circular concentric heating element.

在给定的热充电周期内，在水平排列的空腔中储存热能往往受到能量储存能力的限制。为了解决这一限制，本研究旨在通过计算研究加热元件的形状和位置对圆柱形腔中相变材料（PCM）熔化过程的影响。分析的情况包括同心三角形、移位三角形、同心正方形、移位正方形、同心椭圆和移位椭圆截面，并对采用传统圆形加热元件的基线情况进行评估。结果表明，在水平排列的储热单元中，椭圆截面的移位显著提高了PCM的熔化速度。将标准的圆形加热元件替换为等截面积的移位椭圆形加热元件后，熔化时间缩短约52.8%。为了进一步研究这种改进，对椭圆加热元件的不同宽高比和移位比进行了模拟。研究结果表明，向圆柱体底部移动的长椭圆形状提供了最佳性能。优化后的椭圆加热元件与传统的圆形同心加热元件相比，完全熔化时间缩短了76.9%。

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引用次数: 0