International Journal of Thermofluids最新文献_第8页

Influence of waste cooking oil characteristics on the quality of produced biodiesel 废食用油特性对生物柴油品质的影响

Q1 Chemical Engineering

International Journal of Thermofluids

Pub Date : 2025-11-01 DOI: 10.1016/j.ijft.2025.101469

Samip S. Patil , Dattatray B. Hulwan , Vishal S. Kumbhar , Anand Pandey , Sonawane Chandrakant , Rahul Goyal , Subhav Singh , Deekshant Varshney , Choon Kit Chan

The increasing global energy demand and the depletion of fossil fuels have intensified interest in renewable alternatives such as biodiesel. Waste cooking oil (WCO) offers a sustainable feedstock option, addressing both energy and waste management challenges. However, the effect of repeated frying on oil quality and biodiesel performance remains inadequately explored. This study investigates the influence of multiple frying cycles on the properties and yield of biodiesel derived from various waste cooking oils. Four common edible oils—palm, soybean, sunflower, and peanut—along with a composite mixture, were collected after 0, 1, 3, 6, 9, and >9 frying uses. A total of 30 oil samples were converted into biodiesel via transesterification, and key fuel properties—density, viscosity, calorific value, flash point, pour point, and cetane number—were evaluated relative to conventional diesel. An optimal biodiesel yield of 98.05 % was achieved from the mixed-oil sample reused for more than nine cycles. Transesterification effectively reduced viscosity and density to diesel-like levels. Although the cetane number declined gradually (from 60–65 for fresh oils to 45–50 after extended use) due to thermal degradation of unsaturated fatty acids, values remained within acceptable limits. Diesel exhibited a slightly higher calorific value, but the mixed-oil biodiesel showed minimal deterioration across cycles. Overall, repeatedly used waste cooking oils demonstrated strong potential for producing high-quality biodiesel, highlighting their viability as a renewable alternative to fossil diesel.

随着全球能源需求的增加和化石燃料的枯竭，人们对生物柴油等可再生替代品的兴趣日益浓厚。废食用油（WCO）提供了一种可持续的原料选择，解决了能源和废物管理的挑战。然而，反复煎炸对油脂质量和生物柴油性能的影响尚未得到充分的探讨。本研究考察了多次煎炸循环对以各种废食用油为原料制备生物柴油性能和产率的影响。四种常见的食用油——棕榈油、豆油、葵花籽油和花生油——以及一种复合混合物，分别在0、1、3、6、9和9次油炸后收集。总共30个油样通过酯交换反应转化为生物柴油，并相对于传统柴油评估了燃料的关键性能——密度、粘度、热值、闪点、倾点和十六烷值。混合油样品重复使用9次以上，生物柴油的最佳产率为98.05%。酯交换反应有效地降低了粘度和密度到类似柴油的水平。尽管由于不饱和脂肪酸的热降解，十六烷值逐渐下降（从新鲜油的60-65下降到长期使用后的45-50），但值仍在可接受的范围内。柴油表现出稍高的热值，但混合油生物柴油在整个循环中表现出最小的劣化。总的来说，反复使用的废食用油显示出生产高质量生物柴油的强大潜力，突出了它们作为化石柴油的可再生替代品的可行性。

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引用次数: 0

Impact of central versus side jet impingement configurations on the cooling of a gas turbine leading edge at varying reynolds numbers and rotational speeds: experimental investigations 在不同雷诺数和转速下，中央和侧面射流冲击结构对燃气轮机前缘冷却的影响：实验研究

Q1 Chemical Engineering

International Journal of Thermofluids

Pub Date : 2025-11-01 DOI: 10.1016/j.ijft.2025.101464

Ahmad Alqasrawi , Emad Elnajjar , Amin Safi , Mohammad O. Hamdan , Salah A.B. Al Omari

This experimental study investigated the cooling performance of two jet impingement configurations central and side. The effects of Reynolds numbers ranging from 5000 to 11,000 and rotation speeds ranging from 0 to 200 rpm on the total heat transfer performance represented by the averaged surface Nusselt Number were investigated for central and side jet configurations. At a high rotation speed, the side jet configurations displayed a greater average Nusselt number than the central jets. At a low rotation speed, both layouts yielded similar average Nusselt numbers. For the central jets, increasing the rotation speeds marginally increased the average Nusselt number. Meanwhile, for the side jets, it resulted in a considerable increase in the average Nusselt number. At a low rpm and in both configurations, the average Nusselt number increased with the Reynolds number. At high rotational speeds, the average Nusselt number increased slightly for the central jet arrangement. However, for side jet configurations, increasing the Reynolds number marginally reduced the average Nusselt number. The experimental results show the effects of various parameters on jet impingement cooling, provide information on optimal heat removal for maximizing thermal effectiveness, and aid in assessing the influences of side and central layouts on the overall heat transfer performance and average Nusselt number.

实验研究了中央和侧面两种射流冲击方式的冷却性能。研究了中心射流和侧面射流配置下，雷诺数为5000 ~ 11000，转速为0 ~ 200 rpm对平均表面努塞尔数表示的总传热性能的影响。在高转速下，侧喷流的平均努塞尔数比中心喷流大。在低旋转速度下，两种布局产生相似的平均努塞尔数。对于中心喷流，增加旋转速度会略微增加平均努塞尔数。同时，对于侧喷流，它导致平均努塞尔数显著增加。在低转速和两种配置下，平均努塞尔数随雷诺数增加而增加。在高转速下，中心射流布置的平均努塞尔数略有增加。然而，对于侧射流构型，增加雷诺数会略微降低平均努塞尔数。实验结果显示了不同参数对射流冲击冷却的影响，为最大化热效率提供了最佳排热信息，并有助于评估侧面和中心布局对整体传热性能和平均努塞尔数的影响。

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引用次数: 0

MHD Casson fluid flow in C-type lid-driven cavity with viscous dissipation MHD卡森流体在具有粘性耗散的c型盖驱动腔中的流动

Q1 Chemical Engineering

International Journal of Thermofluids

Pub Date : 2025-11-01 DOI: 10.1016/j.ijft.2025.101467

Ram Dhan Mahla , Sharad Sinha , Kavita Jat , Manoj Kumar Nahlia , Kalpna Sharma , Prasun Choudhary

This study investigates the magnetohydrodynamics Casson fluid flow inside a C-type lid-driven cavity under the influence of viscous dissipation and an inclined magnetic field. Such flow configurations are not only of fundamental scientific interest but also play a vital role in various engineering and industrial applications. The problem is formulated by considering convection-driven motion within the cavity and is mathematically modeled through the governing conservation equations of mass, momentum, and energy. To facilitate numerical treatment and comparative analysis, the system is transformed into a dimensionless form. The resulting nonlinear equations are solved using the Galerkin finite element method (GFEM). The effects of key physical parameters on flow circulation and thermal transport are analyzed in terms of streamlines and isotherms, providing detailed insight into the convective behavior of Casson fluids in confined geometries. A comparative analysis of the streamlines and isotherm lines are presented through graphical representations to highlight the role of distinct parameters and cavity driving mechanisms in shaping the fluid motion and heat transfer patterns. It is observed that an increase in the angle of inclination (

0 \leq ψ \leq π / 2

) of the magnetic fields increase flow circulation. Additionally, heat distribution inside the C-type cavity also increases with

ψ

. Further, it is also observed that flow circulation enhances for higher values of the Casson parameter (

0 \leq γ \leq 10

), due to lower shear rate. The findings of this study are expected to contribute to the design and optimization of engineering systems involving non-Newtonian fluids and MHD flows in cavity configurations.

研究了粘性耗散和倾斜磁场作用下c型盖驱动腔内卡森流体的磁流体力学特性。这种流动结构不仅具有重要的科学意义，而且在各种工程和工业应用中起着至关重要的作用。该问题是通过考虑腔内对流驱动的运动而制定的，并通过质量、动量和能量的控制守恒方程进行数学建模。为了便于数值处理和比较分析，将系统转换为无量纲形式。采用伽辽金有限元法对非线性方程进行了求解。从流线和等温线的角度分析了关键物理参数对流动循环和热输运的影响，为卡森流体在受限几何条件下的对流行为提供了详细的见解。通过图形表示对流线和等温线进行了比较分析，以突出不同参数和空腔驱动机制在形成流体运动和传热模式中的作用。观察到，随着磁场倾角（0≤ψ≤π/2）的增加，流动循环增加。此外，c型腔内的热分布也随着ψ的增大而增大。此外，还观察到，由于剪切速率较低，当Casson参数值较高（0≤γ≤10）时，流动循环增强。本研究的发现有望有助于设计和优化涉及非牛顿流体和MHD在空腔结构中的流动的工程系统。

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引用次数: 0

Differential transformation method for magnetohydrodynamic penta hybrid nanofluid flow with gyrotactic microorganisms in stenosed arteries 狭窄动脉中带有陀螺效应微生物的磁流体动力学五元混合纳米流体流动的微分变换方法

Q1 Chemical Engineering

International Journal of Thermofluids

Pub Date : 2025-11-01 DOI: 10.1016/j.ijft.2025.101477

Mehdi Mahboobtosi, Davood Domiri Ganji, Fateme Nadalinia Chari

The study of blood flow in stenosed arteries is essential for understanding vascular diseases and improving therapeutic strategies. This work investigates the behavior of penta hybrid nanofluid (PHNF) Casson flow in porous stenosed arteries under the combined influence of gyrotactic microorganisms and magnetic fields. The objective is to develop a comprehensive model that captures the coupled effects of non-Newtonian rheology, nanoparticle suspension, arterial wall permeability, and microbial activity. To achieve this, the Differential Transformation Method (DTM) is employed as a semi-analytical approach, offering efficient and accurate solutions for nonlinear biofluid dynamics. The findings show that blood velocity rises with increasing Darcy and Grashof numbers, while it decreases with higher Casson parameters, magnetic intensities, and nanoparticle concentrations. Temperature is reduced by stronger convection but enhanced by thermal radiation, whereas microorganism concentration declines with greater flow parameter and Schmidt number. Skin friction is lowered by higher permeability and Casson effects but elevated by magnetic influence, and the Nusselt number increases with buoyancy and radiation effects. These results provide new insights into the interplay of fluid mechanics, heat transfer, and microbial dynamics in vascular systems, with potential applications in nanomedicine, targeted drug delivery, and the management of cardiovascular diseases.

研究狭窄动脉的血流对理解血管疾病和改善治疗策略至关重要。本文研究了在旋趋微生物和磁场共同作用下，五杂化纳米流体（PHNF）卡森流在多孔狭窄动脉中的行为。目的是建立一个综合模型，捕捉非牛顿流变性、纳米颗粒悬浮液、动脉壁渗透性和微生物活性的耦合效应。为此，采用微分变换方法（DTM）作为半解析方法，为非线性生物流体动力学提供高效、准确的解决方案。研究结果表明，血流速度随着达西和格拉什夫数的增加而上升，而随着卡森参数、磁场强度和纳米颗粒浓度的增加而下降。强对流使温度降低，热辐射使温度升高，而微生物浓度随着流量参数和施密特数的增大而降低。表面摩擦力因高渗透性和卡森效应而降低，但因磁影响而升高，努塞尔数因浮力和辐射效应而增加。这些结果为血管系统中流体力学、传热和微生物动力学的相互作用提供了新的见解，在纳米医学、靶向给药和心血管疾病管理方面具有潜在的应用前景。

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引用次数: 0

Analytical solution of Marangoni convection flow of ethylene glycol-based nanofluid with heat transfer analysis 基于传热分析的乙二醇基纳米流体Marangoni对流解析解

Q1 Chemical Engineering

International Journal of Thermofluids

Pub Date : 2025-11-01 DOI: 10.1016/j.ijft.2025.101462

Ali Rehman , Mustafa Inc , Edrisa Jawo , K. Sudarmozhi

In microelectronics, aerospace, and chemical processing industries, advanced thermal management requires specialized techniques for heat and mass transfer at interfaces to optimize and ensure the reliability of the system. The focus of this study revolves around the MHD MC of ethylene glycol-based nanofluids (SiO₂ and TiO₂) for the first time in the literature. The aim is to assess the flow and heat transfer characteristics over a bidirectionally stretching surface with respect to the combined effects of the Marangoni parameter, volume fraction of the nanoparticle, Grashof number, Prandtl number, and Eckert number. The nonlinear governing PDEs of the flow are simplified with the use of a similarity transformation and converted to ODEs, which are then solved analytically with the HAM. Various velocity and temperature fields are computed, and the skin friction and NN are parametrically explained. Regarding the magnetic parameter, the dominant flow and boundary velocity are suppressed by 30%, while surface heat transfer increases by 20% with a higher nanoparticle volume fraction. Also, more convective flow is achieved with a rise in the Marangoni and Grashof numbers, and the highest NN is recorded with specific physical parameter combinations. The developed framework, along with the results, provides evidence of the vital role that interaction effects play within the scope of MFs and nanoparticle-enhanced fluids, as well as in the potential development of more advanced and effective nanofluid-based cooling and thermal control systems. In relation to specific engineering fields and disciplines, the results hold significance for cooling microelectronics, thermal management in the aerospace industry, and more refined heat exchangers in the chemical industry.

在微电子、航空航天和化学加工行业，先进的热管理需要专门的技术来优化和确保系统的可靠性。本文首次围绕乙二醇基纳米流体（SiO2和TiO2）的MHD MC进行了研究。目的是在马兰戈尼参数、纳米颗粒体积分数、格拉索夫数、普朗特数和埃克特数的综合影响下，评估双向拉伸表面上的流动和传热特性。利用相似变换对流场的非线性控制偏微分方程进行简化，并将其转化为偏微分方程，再用HAM进行解析求解。计算了各种速度场和温度场，并对表面摩擦和神经网络进行了参数化解释。在磁性参数方面，随着纳米颗粒体积分数的增加，主导流和边界速度被抑制了30%，而表面换热增加了20%。此外，随着Marangoni和Grashof数的增加，对流流量增加，特定物理参数组合记录的NN最高。所开发的框架和结果提供了相互作用效应在纳米流体和纳米颗粒增强流体范围内发挥重要作用的证据，以及在更先进和有效的纳米流体冷却和热控制系统的潜在发展中发挥重要作用。在特定的工程领域和学科中，研究结果对微电子冷却、航空航天工业的热管理以及化学工业中更精细的热交换器具有重要意义。

{"title":"Analytical solution of Marangoni convection flow of ethylene glycol-based nanofluid with heat transfer analysis","authors":"Ali Rehman , Mustafa Inc , Edrisa Jawo , K. Sudarmozhi","doi":"10.1016/j.ijft.2025.101462","DOIUrl":"10.1016/j.ijft.2025.101462","url":null,"abstract":"<div><div>In microelectronics, aerospace, and chemical processing industries, advanced thermal management requires specialized techniques for heat and mass transfer at interfaces to optimize and ensure the reliability of the system. The focus of this study revolves around the MHD MC of ethylene glycol-based nanofluids (SiO<sub>2</sub> and TiO<sub>2</sub>) for the first time in the literature. The aim is to assess the flow and heat transfer characteristics over a bidirectionally stretching surface with respect to the combined effects of the Marangoni parameter, volume fraction of the nanoparticle, Grashof number, Prandtl number, and Eckert number. The nonlinear governing PDEs of the flow are simplified with the use of a similarity transformation and converted to ODEs, which are then solved analytically with the HAM. Various velocity and temperature fields are computed, and the skin friction and NN are parametrically explained. Regarding the magnetic parameter, the dominant flow and boundary velocity are suppressed by 30%, while surface heat transfer increases by 20% with a higher nanoparticle volume fraction. Also, more convective flow is achieved with a rise in the Marangoni and Grashof numbers, and the highest NN is recorded with specific physical parameter combinations. The developed framework, along with the results, provides evidence of the vital role that interaction effects play within the scope of MFs and nanoparticle-enhanced fluids, as well as in the potential development of more advanced and effective nanofluid-based cooling and thermal control systems. In relation to specific engineering fields and disciplines, the results hold significance for cooling microelectronics, thermal management in the aerospace industry, and more refined heat exchangers in the chemical industry.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"30 ","pages":"Article 101462"},"PeriodicalIF":0.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145417029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Optimizing UNIQUAC model parameters using an enhanced evolutionary algorithm: applications in vapor–liquid equilibrium modeling 使用改进的进化算法优化UNIQUAC模型参数：在汽液平衡建模中的应用

Q1 Chemical Engineering

International Journal of Thermofluids

Pub Date : 2025-11-01 DOI: 10.1016/j.ijft.2025.101459

Swati Yadav, Rakesh Angira

Parameter estimation in thermodynamic models is challenging due to nonlinearity, flat objective functions near optima, poorly scaled models, and nondifferential terms. This study introduces an enhanced algorithm, the Improved Opposite Point-based Differential Evolution (IOPDE), building on the previously developed OPDE algorithm. IOPDE incorporates generation jumping guided by an adaptive Jumping Rate (JR) strategy to improve convergence speed, solution diversity, and robustness. The performance of Differential Evolution (DE), OPDE, and IOPDE is evaluated on vapor-liquid equilibrium (VLE) modeling problems involving binary, ternary, and quaternary systems. The least-squares approach is used for objective function minimization to estimate interaction parameters for the UNIQUAC model. Algorithm performance is assessed using metrics such as the number of function evaluations (NFE), success rate (SR), and overall acceleration rate (AR). Meanwhile, the quality of parameter estimation is evaluated via average absolute percentage error (%AAPE) and average absolute relative deviation (AARD%). Results indicate that the estimated parameters and %AAPE values either match or exceed those found in previous studies. The AARD% values indicate excellent agreement between calculated and experimental pressures in most cases. The best coefficient of determination (R²) is observed for the ternary system acetone(1) + chloroform(2) + methanol(3), confirming an excellent fit. IOPDE consistently shows high convergence speed, robustness, and a 100 % success rate in most cases, excelling in high-dimensional problems. Compared to DE and OPDE, IOPDE achieves ARs of 6.19 % and 2.67 %, respectively. Overall, IOPDE emerges as a promising approach for robust and efficient parameter estimation in complex thermodynamic models.

热力学模型中的参数估计是具有挑战性的，因为非线性、平坦的目标函数接近最优、低比例模型和非微分项。本研究在先前开发的OPDE算法的基础上引入了一种增强算法，即改进的对点差分进化（IOPDE）。IOPDE采用了由自适应跳跃率（JR）策略引导的世代跳跃，提高了收敛速度、解的多样性和鲁棒性。差分演化（DE）、OPDE和IOPDE的性能在涉及二元、三元和四元系统的气液平衡（VLE）建模问题上进行了评估。采用最小二乘方法对UNIQUAC模型的目标函数进行最小化估计。算法性能通过函数评估次数（NFE）、成功率（SR）和整体加速率（AR）等指标进行评估。同时，用平均绝对百分比误差（%AAPE）和平均绝对相对偏差（AARD%）来评价参数估计的质量。结果表明，估计的参数和%AAPE值符合或超过了以往的研究结果。在大多数情况下，AARD%值表明计算压力和实验压力之间非常吻合。在丙酮(1)+氯仿(2)+甲醇(3)三元体系中，测定系数R2最佳，证实了良好的拟合性。在大多数情况下，IOPDE始终表现出较高的收敛速度、鲁棒性和100%的成功率，在高维问题上表现出色。与DE和OPDE相比，IOPDE的ar值分别为6.19%和2.67%。总的来说，IOPDE是一种很有前途的方法，可以在复杂的热力学模型中进行鲁棒和有效的参数估计。

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引用次数: 0

Design of artificial neural networks for darcy-forchheimer flow of boger hybrid nanofluid with CattaneoChristov theory: Thermofluidic applications 基于CattaneoChristov理论的boger混合纳米流体darcy-forchheimer流人工神经网络设计：热流体应用

Q1 Chemical Engineering

International Journal of Thermofluids

Pub Date : 2025-11-01 DOI: 10.1016/j.ijft.2025.101473

Hussein Ibrahim Hussein , Abdulbasit A. Darem , Asma A. Alhashmi , Nodira Nazarova , Jihad Younis , Munawar Abbas , Hakim AL Garalleh , Amr Alalawi

This study investigates the effects of Marangoni convection on the Darcy-Forchheimer flow of MHD Boger fluid across a sheet using CattaneoChristov heat and mass flux model using artificial neural networks and the Levenberg–Marquardt scheme. The proposed artificial neural network model for Darcy-Forchheimer flow of Boger hybrid nanofluid using CattaneoChristov theory has important thermofluidic applications in engineering and industrial processes that require accurate heat and mass transport management. Its ability to capture non-Fourier heat conduction and resist porous media makes it ideal for optimizing cooling in high-temperature electronics, improving heat exchangers in geothermal and solar-thermal systems, improving thermal management in energy storage devices, and designing efficient thermal barrier coatings. The use of artificial neural networks allows for efficient prediction and optimization of flow and heat transfer characteristics, saving computational time and enabling real-time control in engineering applications. Similarity variables are used to transform nonlinear partial differential equations into nonlinear ordinary differential equations. Numerical results are simulated using the Bvp4c. The approximate solutions for each case are then analyzed using Levenberg Marquardt artificial neural networks for testing, training, and validation. The Levenberg Marquardt artificial neural networks are validated by regression studies, histogram analysis and mean square error. The results are shown to show the outcome of different physical conditions on the associated distributions.

本文采用人工神经网络和Levenberg-Marquardt格式的CattaneoChristov热和质量通量模型，研究了Marangoni对流对MHD Boger流体在薄片上Darcy-Forchheimer流动的影响。基于CattaneoChristov理论提出的Boger混合纳米流体Darcy-Forchheimer流动的人工神经网络模型在需要精确的热量和质量传递管理的工程和工业过程中具有重要的热流体应用。其捕获非傅立叶热传导和抵抗多孔介质的能力使其成为优化高温电子设备冷却，改善地热和太阳能热系统中的热交换器，改善储能设备中的热管理以及设计高效热障涂层的理想选择。人工神经网络的使用可以有效地预测和优化流动和传热特性，节省计算时间并实现工程应用中的实时控制。利用相似变量将非线性偏微分方程转化为非线性常微分方程。利用Bvp4c对数值结果进行了模拟。然后使用Levenberg Marquardt人工神经网络对每种情况的近似解进行分析，以进行测试、训练和验证。通过回归研究、直方图分析和均方误差对Levenberg - Marquardt人工神经网络进行了验证。结果显示了不同物理条件对相关分布的影响。

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引用次数: 0

Synergistic effects of micro-hole injection and film cooling for increasing the cooling effectiveness: A numerical investigation 微孔喷射和气膜冷却对提高冷却效率的协同效应：数值研究

Q1 Chemical Engineering

International Journal of Thermofluids

Pub Date : 2025-11-01 DOI: 10.1016/j.ijft.2025.101497

Milad Mahdian Dowlatabadi , Saeed Rostami , Sepehr Sheikhlari , Khodayar Javadi

The continuous drive to improve the efficiency and power output of gas turbines has led to the need for advanced cooling strategies that can effectively dissipate high thermal loads. This study presents a comparative analysis of the thermal performance of various micro-hole configurations integrated with a main cooling hole, highlighting their synergistic effects on film-cooling effectiveness and flow behavior. Five distinct configurations were evaluated at three different blowing ratios of 0.25, 0.5, and 1.0. The SST k-ω turbulence model is employed to simulate the turbulent flow. Outcomes reveal that regardless of the configuration of micro-holes, their combination with the main hole of film cooling could increase the cooling effectiveness. Also, the comparison of different configurations demonstrates that the Quad-type (QT) configuration consistently outperformed the other designs at all tested blowing ratios. At a blowing ratio of 0.5, the QT configuration exhibited the highest centerline cooling effectiveness, with a value of 0.44 compared to 0.37 for the Step-type (ST) configuration at the X/D = 30 location. Additionally, the QT configuration had the highest spanwise-averaged cooling effectiveness, with a value of 0.3170 at X/R = 20, representing a 54.9 % improvement over the previously proposed design. Furthermore, the QT configuration demonstrated the best cooling uniformity, as indicated by the lowest CUC among the investigated configurations.

不断提高燃气轮机的效率和功率输出导致需要先进的冷却策略，以有效地消散高热负荷。本研究对比分析了与主冷却孔集成的不同微孔构型的热性能，强调了它们对气膜冷却效果和流动行为的协同效应。在0.25、0.5和1.0三种不同的吹气比下评估了五种不同的配置。采用SST k-ω湍流模型模拟湍流流动。结果表明，无论微孔的配置如何，微孔与气膜冷却主孔的组合都能提高冷却效果。此外，不同配置的比较表明，qud型（QT）配置始终优于其他设计在所有测试的吹气比。在吹气比为0.5时，QT组态表现出最高的中心线冷却效率，其值为0.44，而X/D = 30位置的阶梯型（ST）组态为0.37。此外，QT配置具有最高的展向平均冷却效率，在X/R = 20时的值为0.3170，比先前提出的设计提高了54.9%。此外，QT配置显示出最佳的冷却均匀性，正如所调查配置中最低的CUC所表明的那样。

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引用次数: 0

Experimental and theoretical investigation of vacuum-based seawater desalination system driven by ultra-low temperature heat source 超低温热源驱动真空海水淡化系统的实验与理论研究

Q1 Chemical Engineering

International Journal of Thermofluids

Pub Date : 2025-11-01 DOI: 10.1016/j.ijft.2025.101502

Tongchana Thongtip, Wichean Singmai, Pichet Janpla, Teerapharp Amornsawaddirak, Kittiwoot Sutthivirode

Sustainable freshwater plays a key role in human life and the rapid growth of industry. However, freshwater sources are limited even when seawater constitutes most of the available water on the earth. Converting seawater into freshwater via desalination, particularly using low-grade heat, presents a promising solution for sustainable freshwater need. This paper proposes a theoretical and experimental investigation of a thermally driven vacuum desalination system (TDVDS). The primary objective is to demonstrate the system’s ability to produce freshwater when driven by an ultra-low temperature heat source (50 – 70 °C), while the heat sink is maintained at 30 °C. A mathematical model is developed to predict freshwater production and assess the TDVDS’s working characteristics. An experimental test rig is constructed to provide validation data. The simulated results are validated against experimental data under identical working conditions to demonstrate the model’s accuracy. The TDVDS is found to operate stably and provide acceptable performance, producing freshwater with a thermal efficiency of 54 – 67 %. An discrepancy of around 5 – 10 % is observed between simulated and experimental results. Freshwater production increases linearly with distillation time, indicating a constant evaporation rate under steady-state operation. An increase in heat source temperature yields a higher freshwater production and improved thermal efficiency. The mathematical model proved to be an efficient tool for assessing the system’s working characteristics. The contributions of this work serve as a reference case for further development and practical application of the TDVDS, for which sustainable freshwater is a major achievement.

可持续的淡水在人类生活和工业的快速发展中起着关键作用。然而，淡水资源是有限的，即使海水构成了地球上大部分可用的水。通过海水淡化，特别是使用低品位热量，将海水转化为淡水，为可持续的淡水需求提供了一个有希望的解决方案。本文对热驱动真空脱盐系统（tdvd）进行了理论和实验研究。测试的主要目标是验证系统在超低温热源（50 - 70°C）驱动下生产淡水的能力，同时散热器保持在30°C。建立了预测淡水产量和评价tdvd工作特性的数学模型。搭建了实验试验台，提供验证数据。仿真结果与实验数据在相同工况下进行了对比，验证了模型的准确性。研究发现，tdvd运行稳定，性能良好，生产的淡水热效率为54 - 67%。在模拟结果和实验结果之间观察到大约5 - 10%的差异。淡水产量随蒸馏时间线性增加，表明在稳态运行下蒸发速率恒定。热源温度的增加会产生更高的淡水产量，并提高热效率。该数学模型是评估系统工作特性的有效工具。这项工作的贡献可作为进一步发展和实际应用tdvd的参考案例，可持续淡水是tdvd的一项主要成就。

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引用次数: 0

A short-term load forecasting method for integrated regional energy systems based on multivariate phase space reconstruction 基于多元相空间重构的综合区域能源系统短期负荷预测方法

Q1 Chemical Engineering

International Journal of Thermofluids

Pub Date : 2025-11-01 DOI: 10.1016/j.ijft.2025.101472

Jun Ma , Xiaobo Cao , Xin Yang , Peng Ren , Dan Shao , Yusen Zhang

To more accurately describe the load evolution law and its relationship with other variables, obtain the phase-space representation of the load data, and achieve accurate prediction of the short-term load of the DIES, a short-term load prediction method for the DIES based on multivariate phase-space reconstruction is proposed. Through correlation analysis of the short-term loads of DIES, the relationship between electric, cooling, and heating loads and meteorological characteristics is evaluated using the Pearson correlation coefficient to determine the input multivariate variables of the prediction model. The multivariate phase-space reconstruction technique is employed, and the delay time and embedding dimensions of the time series of the multivariate variables are determined by using the CC algorithm to optimize the phase-space reconstruction process, obtaining the phase-space representation of the electric, cooling, and heating loads and meteorological characteristics. The coupling characteristics of the electricity, cooling and heating loads and the meteorological characteristics over time are explored. Based on the Kalman filtering algorithm, a short-term load forecasting model for DIES is established, and the phase points reconstructed in phase space are used as the state vectors, which constitute the state-space description of the phase points. Kalman filtering theory is applied to realize the accurate forecasting of future short-term loads. The experimental results demonstrate that the method can clarify the correlation between electricity, cooling, and heating loads, and meteorological data through Pearson correlation analysis, and accordingly select an 8-dimensional multivariate time series for short-term load prediction. This method can accurately predict short-term changes in electricity, cooling, and heating loads with high prediction accuracy and stability. The root mean square error is 0.52 MW, the mean absolute error is 0.38 MW, the mean absolute percentage error is 2.1 %, and the p-values are all <0.01.

为了更准确地描述负荷演化规律及其与其他变量的关系，获得负荷数据的相空间表示，实现对die短期负荷的准确预测，提出了一种基于多变量相空间重构的die短期负荷预测方法。通过对die短期负荷的相关分析，利用Pearson相关系数评估电、冷、热负荷与气象特征之间的关系，确定预测模型的输入多元变量。采用多变量相空间重构技术，利用CC算法优化相空间重构过程，确定多变量时间序列的延迟时间和嵌入维数，得到电、冷、热负荷和气象特征的相空间表示。探讨了电、冷、热负荷与气象特征随时间的耦合特征。基于卡尔曼滤波算法，建立了die短期负荷预测模型，并以相空间重构的相点作为状态向量，构成了相点的状态空间描述。应用卡尔曼滤波理论实现了对未来短期负荷的准确预测。实验结果表明，该方法可以通过Pearson相关分析明确电、冷、热负荷与气象数据之间的相关性，并据此选择8维多元时间序列进行短期负荷预测。该方法能够准确预测电力、制冷、供暖负荷的短期变化，预测精度高，稳定性好。均方根误差为0.52 MW，平均绝对误差为0.38 MW，平均绝对百分比误差为2.1%，p值均为<；0.01。

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