Experimental Thermal and Fluid Science最新文献_第7页

Experimental study on cavitation pattern and near-field spray characteristics of methanol in the scaled-up fuel injection nozzle 甲醇在放大喷油器内的空化模式及近场喷射特性实验研究

IF 3.3 2区工程技术 Q2 ENGINEERING, MECHANICAL

Experimental Thermal and Fluid Science

Pub Date : 2026-01-15 Epub Date: 2025-09-26 DOI: 10.1016/j.expthermflusci.2025.111624

Wei Huang , Yizhou Yang , Zhixia He , Zhen Yang , Shengnan Zhang , Yuanfeng Zhao , Wei Guan , Genmiao Guo

Methanol, as a clean fuel, particularly when synthesized from green electricity and recycled CO₂, has zero-carbon potential and is gaining increasing attention. However, due to methanol’s corrosivity and unique physical properties, designing high-pressure injectors for methanol engines presents numerous challenges. This study presents the first comprehensive analysis of methanol’s flow characteristics and near-field spray behavior using a scaled-up optical nozzle. Rounded and sharp nozzles were used to investigate vortex-induced string cavitation and geometry-induced sheet cavitation. By adjusting the needle lift and injection pressure, the onset and development of various cavitation patterns in methanol were studied. Additionally, comparative experiments between methanol and diesel were conducted to analyze the differences in flow and spray characteristics under different cavitation regimes, providing insights for the use of methanol as a replacement for diesel in engines. Experimental results show that methanol’s lower viscosity promotes the exsolution of dissolved gases, forming free gas bubbles that accumulate in the vortex core, thereby enhancing string cavitation. Under identical operating conditions, methanol exhibits a stronger tendency for string cavitation and greater cavitation intensity compared to diesel. In contrast, the difference in geometric-induced cavitation intensity between methanol and diesel is relatively small, attributed to methanol’s less sensitive response to variations in fuel properties.

甲醇作为一种清洁燃料，特别是由绿色电力和回收二氧化碳合成的甲醇，具有零碳潜力，越来越受到关注。然而，由于甲醇的腐蚀性和独特的物理性质，为甲醇发动机设计高压喷油器带来了许多挑战。本研究首次采用放大光学喷嘴对甲醇的流动特性和近场喷雾行为进行了全面分析。采用圆形和尖形喷嘴分别研究了涡致柱状空化和几何致片状空化。通过调整注射针升程和注射压力，研究了甲醇中各种空化模式的发生和发展。此外，还进行了甲醇和柴油的对比实验，分析了不同空化制度下甲醇的流动和喷雾特性的差异，为在发动机中使用甲醇替代柴油提供了见解。实验结果表明，甲醇较低的粘度促进了溶解气体的析出，形成自由气泡积聚在涡核中，从而增强了串的空化作用。在相同工况下，甲醇比柴油表现出更强的空化倾向和更大的空化强度。相比之下，甲醇和柴油在几何诱导空化强度上的差异相对较小，这是由于甲醇对燃料特性变化的响应不太敏感。

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引用次数: 0

Thermally induced nanobubble filaments and cylindrical shock wave formation in colloidal suspension 胶体悬浮液中热诱导纳米气泡细丝和圆柱激波的形成

IF 3.3 2区工程技术 Q2 ENGINEERING, MECHANICAL

Experimental Thermal and Fluid Science

Pub Date : 2026-01-15 Epub Date: 2025-09-24 DOI: 10.1016/j.expthermflusci.2025.111623

Uroš Orthaber, Rok Petkovšek

An interesting phenomenon involving generation of nanobubble filaments in an aqueous colloidal suspension of gold nanoparticles (GNP) is being reported on and discussed in the present paper. The heat for thermally induced nanobubbles is being provided to GNPs by a laser pulse. If specific conditions, such as sufficient laser beam fluence, adequate GNP size and concentration are met self-focusing occurs, which consequently leads to a formation of one or more nanobubble filaments along the beam propagation direction. The nanobubble filaments are made observable by sending a rarefaction wave through the region, where they occur. Depending on the beam fluence, one or more nanobubble filaments are observed and depending on the beam and GNP parameters, the nanobubble filaments may be accompanied by a plasma filament, if thresholds for self-focusing and ionization are exceeded at the same time. In this case a cylindrical shock wave originating from the filament is observed. The present study investigates the influence of GNP size and beam fluence on nanobubble filament formation. It implements a recently developed technique for nanobubble visualization using a rarefaction wave and a multiple illumination pulse technique for shock wave detection.

本文报道并讨论了在金纳米颗粒（GNP）的胶体悬浮液中产生纳米气泡细丝的有趣现象。热诱导纳米气泡的热量由激光脉冲提供给GNPs。如果满足特定条件，如足够的激光束通量、足够的GNP大小和浓度，就会发生自聚焦，从而导致沿光束传播方向形成一个或多个纳米气泡细丝。纳米气泡细丝是通过发送稀薄波穿过它们出现的区域而被观察到的。根据光束的影响，可以观察到一个或多个纳米气泡细丝，根据光束和GNP参数，如果同时超过自聚焦和电离的阈值，纳米气泡细丝可能伴随着等离子体细丝。在这种情况下，观察到从灯丝发出的圆柱形激波。本文研究了GNP尺寸和光束影响对纳米泡丝形成的影响。它实现了最近开发的纳米气泡可视化技术，使用稀疏波和多重照明脉冲技术进行冲击波检测。

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引用次数: 0

Proper orthogonal decomposition of transient cavitating flow with emphasis on thermodynamic effect 适当的正交分解瞬态空化流，重点考虑热力学效应

IF 3.3 2区工程技术 Q2 ENGINEERING, MECHANICAL

Experimental Thermal and Fluid Science

Pub Date : 2026-01-15 Epub Date: 2025-10-16 DOI: 10.1016/j.expthermflusci.2025.111627

Bin Xu , Liwen Zhang , Desheng Zhang , Xi Shen , Weibin Zhang , B.P.M.Bart van Esch

This study employs data-driven modal decomposition methods to identify dominant coherent structures within fluoroketone cavitating flow around a NACA0015 hydrofoil, with particular emphasis on thermodynamic effects. Numerical simulations under isothermal and non-isothermal conditions provide snapshot data sequences within a thermosensitive cavitating flow modeling framework. Q-criterion vortex identification analyzes vortical structure evolution, while Proper Orthogonal Decomposition (POD) extracts dominant coherent structures and quantifies energy distribution characteristics. Power spectral density analysis identifies characteristic frequencies, and flow field reconstruction validates modal contributions. Results demonstrate that thermodynamic effects significantly suppress cavitation phenomena by reducing cavity volumes and prolonging evolution cycles through latent heat absorption-induced local temperature decreases and saturated vapor pressure reduction. The dominant shedding frequency exhibits strong correlation with vortex structure periodicity. POD analysis reveals that thermal effects preserve spatial topological characteristics of coherent structures while substantially attenuating dynamic intensities across all leading modes. Non-isothermal conditions require additional modes for equivalent reconstruction accuracy, indicating enhanced flow complexity due to temperature gradient-induced instabilities. The analysis demonstrates that thermodynamic effects fundamentally alter cavitating flow dynamics through systematic suppression of coherent structure intensities while preserving spatial organizational patterns. Enhanced energy dispersion across multiple modes under thermal influence necessitates modified modeling approaches for accurate flow prediction and control in thermosensitive cavitating systems.

本研究采用数据驱动的模态分解方法来识别NACA0015水翼周围氟酮空化流中的优势相干结构，并特别强调热力学效应。等温和非等温条件下的数值模拟提供了热敏空化流建模框架内的快照数据序列。q准则涡识别分析了涡旋结构演变，适当正交分解（POD）提取优势相干结构并量化能量分布特征。功率谱密度分析确定了特征频率，流场重建验证了模态贡献。结果表明，热力效应通过潜热吸收引起的局地温度降低和饱和蒸汽压降低显著抑制空化现象，减少空化体积，延长演化周期。主导脱落频率与涡结构周期性有很强的相关性。POD分析表明，热效应保留了相干结构的空间拓扑特征，同时大大减弱了所有主模态的动态强度。非等温条件需要额外的模式来获得等效的重建精度，这表明由于温度梯度引起的不稳定性增加了流动的复杂性。分析表明，热力学效应通过系统地抑制相干结构强度，同时保持空间组织模式，从根本上改变了空化流动动力学。在热敏空化系统中，热影响下多模态能量弥散增强，需要改进建模方法以实现精确的流动预测和控制。

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引用次数: 0

Water droplet impact-freezing behaviors on cold superhydrophobic cylindrical surfaces 超疏水圆柱表面水滴的冲击冻结行为

IF 3.3 2区工程技术 Q2 ENGINEERING, MECHANICAL

Experimental Thermal and Fluid Science

Pub Date : 2026-01-15 Epub Date: 2025-09-07 DOI: 10.1016/j.expthermflusci.2025.111613

Qi Guo , Jiaxiang Zheng , Zunru Fu , Hui Gao , Dongsheng Wen

The impact-freezing behavior of droplets on cold superhydrophobic cylinders was investigated using silica-based coating and a self-constructed low-temperature droplet impact experimental platform. The effects of surface temperature, droplet impact velocity, and surface curvature on droplet dynamics and freezing behavior were systematically investigated. Experimental results revealed that the surface temperature predominantly inhibited droplet retraction, with limited influence on the spreading stage. The effect of surface curvature was found to be more complicated. Droplets tended to freeze rather than rebound at smaller curvature diameters, highlighting the dominance of heat transfer. As the curvature diameter increased, fluid flow effects became more pronounced, leading to a larger circumferential spreading factor. Then, this factor gradually decreased with further increases in diameter and eventually stabilized. Experiment also showed that the circumferential maximum spreading factor was positively correlated with both the surface supercooling degree and the Weber number, but negatively correlated with the curvature diameters ratio. Notably, the influence of surface temperature on impact-freezing was highly related to surface curvature. These findings provided insights into optimizing structured superhydrophobic surfaces for anti-icing performance.

采用硅基涂层和自行搭建的低温液滴撞击实验平台，研究了液滴在超疏水圆筒上的撞击冻结行为。系统地研究了表面温度、液滴撞击速度和表面曲率对液滴动力学和冻结行为的影响。实验结果表明，表面温度主要抑制液滴缩回，对扩散阶段的影响有限。表面曲率的影响更为复杂。液滴倾向于在较小的曲率直径处冻结而不是反弹，这突出了传热的优势。随着曲率直径的增大，流体流动效应更加明显，导致周向扩散系数增大。随着直径的进一步增大，该因子逐渐减小，最终趋于稳定。实验还表明，周向最大扩散系数与表面过冷度和韦伯数呈正相关，与曲率直径比呈负相关。值得注意的是，表面温度对冲击冻结的影响与表面曲率高度相关。这些发现为优化结构超疏水表面的抗冰性能提供了见解。

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引用次数: 0

Interfacial characteristics of a perturbed liquid jet in quiescent air 静空气中扰动液体射流的界面特性

IF 3.3 2区工程技术 Q2 ENGINEERING, MECHANICAL

Experimental Thermal and Fluid Science

Pub Date : 2026-01-15 Epub Date: 2025-09-04 DOI: 10.1016/j.expthermflusci.2025.111603

Tianyi Wang, Yannis Hardalupas

The physical understanding of liquid jet breakup in quiescent air remains incomplete due to the complex interactions among influencing parameters and limitations in current measurement techniques. In this study, a needle pin was positioned at the nozzle exit of a liquid jet pressure atomiser to introduce an artificial perturbation of controlled magnitude, enabling an investigation on the influence of flow disturbances on the breakup process. This perturbation is introduced to model potential flow disturbances that may occur inside the nozzle of an atomiser, such as liquid flow separation or cavitation. The interfacial characteristics of the liquid jet, including surface morphology and interfacial motion, were analysed to assess the impact of the imposed perturbation on the breakup process. Optical Connectivity (OC), which transmits a laser beam through the intact liquid core, was employed to capture detailed interface geometry. The instantaneous interfacial characteristics were tracked in time using Optical Flow Velocimetry (OFV) to measure the interfacial velocity. Proper Orthogonal Decomposition (POD) was applied to extract the dominant interfacial wave structures, which were subsequently correlated with interfacial motion to provide a comprehensive assessment of the perturbation effects. The consistency between the dominant interfacial geometry extracted from POD and the measured interfacial velocity further validates the reliability of the OC-OFV technique. The findings reveal that introducing artificial perturbations and adjusting their amplitude can alter the interfacial motion and geometry of the liquid jet by modifying internal flow patterns, which in turn influence the liquid breakup process and the velocity of the resulting liquid fragments. This highlights the significant impact of nozzle disturbances, such as cavitation or manufacturing defects, on atomisation performance. Moreover, the results suggest that applying controlled artificial perturbations could serve as an effective strategy for controlling the breakup process and optimising the resulting spray droplet velocity.

由于影响参数之间复杂的相互作用和现有测量技术的局限性，对静止空气中液体射流破裂的物理认识仍然不完整。在本研究中，在液体射流压力喷雾器的喷嘴出口处放置一个针脚，以引入一个可控量级的人工扰动，从而研究流动扰动对破裂过程的影响。引入这种扰动来模拟可能发生在喷雾器喷嘴内部的潜在流动扰动，例如液体流动分离或空化。分析了液体射流的界面特征，包括表面形貌和界面运动，以评估施加的扰动对破裂过程的影响。光学连通性（OC）通过完整的液体核心传输激光束，用于捕获详细的界面几何形状。利用光流测速仪（OFV）测量界面速度，及时跟踪界面的瞬时特性。应用适当正交分解（POD）提取界面波的优势结构，并将其与界面运动进行关联，从而对扰动效应进行综合评价。从POD中提取的优势界面几何形状与实测界面速度之间的一致性进一步验证了OC-OFV技术的可靠性。研究结果表明，引入人工扰动并调节其振幅可以通过改变内部流动模式来改变液体射流的界面运动和几何形状，从而影响液体破碎过程和产生的液体碎片的速度。这突出了喷嘴干扰（如空化或制造缺陷）对雾化性能的重大影响。此外，研究结果表明，施加可控的人工扰动可以作为控制破碎过程和优化最终雾滴速度的有效策略。

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引用次数: 0

Measurement of dissimilar destruction of turbulent momentum and heat fluxes without instantaneous pressure acquisition 在没有瞬时压力获取的情况下测量湍流动量和热通量的不同破坏

IF 3.3 2区工程技术 Q2 ENGINEERING, MECHANICAL

Experimental Thermal and Fluid Science

Pub Date : 2026-01-15 Epub Date: 2025-09-22 DOI: 10.1016/j.expthermflusci.2025.111621

Toru Mukai, Mamoru Takahashi, Komei Fujikura, Koichi Tsujimoto, Toshitake Ando

Pressure–rate-of-strain and pressure–temperature-gradient statistically contribute to the destruction of turbulent momentum and heat fluxes, respectively. However, in instantaneous fields, both forward (loss) and backward (gain) destruction events can occur. Moreover, dissimilar destruction of turbulent fluxes, such as the forward destruction of momentum flux and backward destruction of heat flux, and vice versa, can arise in shear flows. In this study, we experimentally quantify the dissimilarity of turbulent fluxes in a heated round jet. The destruction of the turbulent fluxes is governed by the pressure-rate-of-strain for the momentum flux and the pressure-temperature-gradient of the heat flux. To circumvent the need for instantaneous pressure fluctuation measurements, we employed a combined probe consisting of an X-type hot-wire and two parallel cold-wire sensors. This setup enabled the quantification of the fraction of total events corresponding to dissimilar flux destruction. The combined probe provided accurate velocity and temperature statistics, including their derivatives, except in the outer regions of the jet, where the mean velocity is extremely small. Furthermore, confidence in measuring intermediate-scale fluctuations, which are related to the destruction of turbulent fluxes, is confirmed. Finally, the joint statistics between the velocity and temperature derivatives indicate that the destruction of turbulent fluxes in a free round jet is highly dissimilar. We find that the coherence of the destruction of turbulent fluxes due to intermediate-scale fluctuations is at most 0.4 and decreases with the streamwise distance from the exit and increasing frequency. Furthermore, approximately half of the instantaneous events exhibit dissimilar destruction of the turbulent fluxes.

压力-应变速率和压力-温度梯度在统计上分别对湍流动量和热通量的破坏有贡献。然而，在瞬时场中，向前（损失）和向后（增益）破坏事件都可能发生。此外，在剪切流动中，湍流通量的不同破坏，如动量通量的前向破坏和热通量的后向破坏，反之亦然。在本研究中，我们通过实验量化了加热圆形射流中湍流通量的差异性。湍流通量的破坏由动量通量的压力-应变速率和热流通量的压力-温度梯度决定。为了避免瞬时压力波动测量的需要，我们采用了由x型热线和两个平行冷线传感器组成的组合探头。这种设置可以量化与不同通量破坏相对应的总事件的比例。联合探针提供了精确的速度和温度统计数据，包括它们的导数，除了在射流的外部区域，那里的平均速度非常小。此外，还证实了测量与湍流通量破坏有关的中尺度波动的可信度。最后，速度导数和温度导数之间的联合统计表明，自由圆射流中湍流通量的破坏是高度不同的。我们发现，中尺度波动对湍流通量破坏的相干性最大为0.4，并且随着离出口的流向距离和频率的增加而减小。此外，大约一半的瞬时事件表现出不同的湍流通量破坏。

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引用次数: 0

Flow and wave characteristics of jet drainage film under crossflow 横流作用下射流疏水膜的流动和波动特性

IF 3.3 2区工程技术 Q2 ENGINEERING, MECHANICAL

Experimental Thermal and Fluid Science

Pub Date : 2026-01-15 Epub Date: 2025-09-10 DOI: 10.1016/j.expthermflusci.2025.111616

Qiuxiang Chen, Xinying Wang, Qiang Li, Hongfei Hu, Haijun Wang

The interaction between jet drainage films and crossflow is widespread in engineering systems such as liquid rocket engines and nuclear reactor emergency cooling systems. In these processes, an understanding of the flow behavior and fluctuation characteristics of drainage films under crossflow is essential. In this study, an experimental system was constructed to investigate the behavior of jet drainage films under crossflow. The spatial evolution of film offset, average film thickness, base film thickness, wave height, and fluctuation characteristics was investigated under varying crossflow velocities using high-speed imaging and spectral confocal measurement techniques. The results show that the drainage film is shifted to the crossflow direction, and the offset increases linearly with the flow distance, which is inversely proportional to the jet Weber number and directly proportional to the crossflow Weber number. The spatial distribution characteristics of the average liquid film thickness, base film thickness, and wave height are jointly influenced by the jet Weber number and crossflow velocity. The cross-sectional averages of liquid film thickness, base film thickness, and wave height exhibit an initial decrease followed by a subsequent increase with flow distance. The standard deviation of the liquid film thickness was significantly and linearly correlated with its average value, with a slope of approximately 0.3. As the crossflow velocity increases, the liquid film fluctuations on the leeward side of the drainage film are significantly suppressed at low jet Weber numbers, while the liquid film fluctuations on the windward side are notably weakened at the high jet Weber number.

射流排水膜与横流之间的相互作用在液体火箭发动机和核反应堆应急冷却系统等工程系统中广泛存在。在这些过程中，了解排水膜在横流作用下的流动行为和波动特征是至关重要的。在本研究中，建立了一个实验系统来研究横流作用下射流疏水膜的行为。利用高速成像和光谱共聚焦测量技术，研究了不同横流速度下的膜偏移量、平均膜厚、基膜厚度、波高和波动特性的空间演变。结果表明：疏水膜向横流方向偏移，偏移量随流动距离的增加呈线性增加，与射流韦伯数成反比，与横流韦伯数成正比；射流韦伯数和横流速度共同影响平均液膜厚度、基膜厚度和波高的空间分布特征。液膜厚度、基膜厚度和波高的截面平均值随着流动距离的增加呈现先减小后增大的趋势。液膜厚度的标准差与其平均值呈显著线性相关，斜率约为0.3。随着横流速度的增加，低射流韦伯数时疏水膜背风侧液膜波动被显著抑制，高射流韦伯数时迎风侧液膜波动被显著减弱。

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引用次数: 0

Heat penetration in reactive porous beds 反应性多孔床的热渗透

IF 3.3 2区工程技术 Q2 ENGINEERING, MECHANICAL

Experimental Thermal and Fluid Science

Pub Date : 2026-01-15 Epub Date: 2025-10-16 DOI: 10.1016/j.expthermflusci.2025.111631

André V. Xavier , Tarek L. Rashwan , Flávio L.F. Bittencourt , Marcio Ferreira Martins

This study investigates how the ignition method, diffusion-, and convection-driven influences heat penetration in a reactive porous bed of coconut-shell charcoal. A series of 28 controlled experiments was conducted under both diffusion- and convection-driven combustion modes, varying ignition protocols and thermocouple depths within a custom-designed combustion cell. The temperature evolution was measured to delineate heat penetration zones, including water condensation, preheating, and chemical reaction fronts. Results reveal that in assisted ignition, continuous external heating sustains combustion and deepens heat penetration by maintaining high-temperature gradients. In contrast, non-assisted ignition, which relies solely on internal heat release, exhibits faster cooling and limited penetration due to early heat loss and extinction risk. Heat maps constructed from the data show broader preheating zones under diffusion conditions and more pronounced condensation layers under convection. These findings highlight the critical role of ignition conditions in modulating thermal gradients and sustaining smoldering fronts, with implications for fire safety, waste-to-energy systems, and porous media combustion modeling.

本研究探讨了点火方式、扩散驱动和对流驱动如何影响椰壳炭反应多孔床的热渗透。在一个定制设计的燃烧电池中，在扩散和对流驱动的燃烧模式、不同的点火方案和热电偶深度下，进行了一系列28项对照实验。通过测量温度演变来描绘热渗透区，包括冷凝水、预热和化学反应前沿。结果表明，在辅助点火过程中，持续的外部加热通过维持高温梯度来维持燃烧并加深热渗透。相比之下，非辅助点火，完全依赖于内部热释放，表现出更快的冷却和有限的穿透，由于早期热损失和熄灭的风险。根据数据构建的热图显示，扩散条件下的预热区更宽，对流条件下的冷凝层更明显。这些发现强调了点火条件在调节热梯度和维持阴燃前沿方面的关键作用，对消防安全、废物转化为能源系统和多孔介质燃烧建模具有重要意义。

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引用次数: 0

Aerodynamic performance analysis of a NACA 63(4)-421 airfoil equipped with a trailing edge slot at suction side NACA 63(4)-421翼型吸力侧后缘狭缝气动性能分析

IF 3.3 2区工程技术 Q2 ENGINEERING, MECHANICAL

Experimental Thermal and Fluid Science

Pub Date : 2026-01-15 Epub Date: 2025-09-04 DOI: 10.1016/j.expthermflusci.2025.111604

Himmet Erdi Tanürün , Abdussamed Yıldız , Mehmet Seyhan

The present work addresses the aerodynamic penalties caused by laminar separation bubbles in low Reynolds number regimes, which are prevalent in UAVs and small wind turbines. The slot design, which has been subjected to experimental validation, offers a passive, cost-effective solution for enhancing aerodynamic efficiency in such critical applications. Therefore, this study investigates the aerodynamic performance of the NACA 63(4)-421 airfoil equipped with a Trailing Edge Slot (TES) at suction side, evaluated through Force Measurement Experiments (FMEs) and Surface Oil Flow Visualization (SOFV) techniques in suction type wind tunnel. To improve flow reattachment and aerodynamic efficiency, the TES slot geometry was designed taking into account the following parameters: slot width ratio, slot angle, slot inlet location, and Coanda radius (r_c), slot outlet suction side radius (r_t), and slot inlet pressure side radius (r_p). Among the four TES configurations tested in the 0° to 30° range; Model 2 (M2) demonstrated superior performance across the investigated angle of attack (AoA) range. The stall angle of M2 was delayed by 3°, reaching 17° compared to the baseline (B1), and the maximum lift coefficient (C_L,max) reached 1.51, corresponding to a 122% increase compared to B1. M2 model significantly reduces the undesired fluctuating lift via jet injection from the slot geometry as compared to the B1 at pre-stall region. At AoAs between 6° and 16°, the high-momentum slot flow effectively interacted with the main flow, re-energizing the boundary layer and enhancing surface attachment. This mechanism directly contributes to delaying the stall. Furthermore, NACA 63(4)-421 airfoil having TES has been demonstrated to re-energise the boundary layer, modify the position of the Laminar Separation Line (LSL), and Turbulent Reattachment Line (TRL) and expand the turbulent flow region. This, in turn, has been shown to enhance surface flow attachment and delay stall by controlling the laminer separation bubble (LSB). The combination of optimized slot geometry and effective flow interaction confirms that TES configurations significantly enhance aerodynamic performance in Re of 9x10⁴.

目前的工作解决了在低雷诺数条件下由层流分离气泡引起的空气动力学惩罚，这在无人机和小型风力涡轮机中很普遍。该狭槽设计已经过实验验证，为提高此类关键应用中的气动效率提供了一种被动、经济的解决方案。因此，本研究通过力测量实验（FMEs）和表面油流可视化（SOFV）技术在吸力型风洞中对NACA 63(4)-421翼型在吸力侧加装后缘槽（TES）的气动性能进行了研究。为了提高流动再附着和气动效率，TES狭缝几何设计考虑了以下参数：狭缝宽度比、狭缝角度、狭缝进口位置、康达半径（rc）、狭缝出口吸力侧半径（rt）和狭缝进口压力侧半径（rp）。在0°至30°范围内测试的四种TES配置中；模型2 （M2）在研究的攻角（AoA）范围内表现出优越的性能。M2失速角比基线（B1）延迟3°，达到17°，最大升力系数（CL,max）达到1.51，比基线（B1）增加122%。与失速前区域的B1相比，M2模型显著减少了通过从槽几何形状喷射而产生的不希望的波动升力。在6°~ 16°AoAs处，高动量槽流与主流有效相互作用，使边界层重新充能，增强了表面附着。这种机制直接有助于延迟失速。此外，具有TES的NACA 63(4)-421翼型已被证明可以重新激活边界层，修改层流分离线（LSL）和湍流再附着线（TRL）的位置，并扩大湍流区域。这反过来又通过控制层膜分离气泡（LSB）来增强表面流动附着并延迟失速。优化后的狭缝几何形状和有效的流动相互作用相结合，证实了TES配置显著提高了9x104 Re的气动性能。

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引用次数: 0

Swirling flow and spray atomization interactions in a swirl cup airblast fuel injector: Venturi outlet angle 旋流杯式喷风喷油器中的旋流与喷雾雾化相互作用：文丘里出口角

IF 3.3 2区工程技术 Q2 ENGINEERING, MECHANICAL

Experimental Thermal and Fluid Science

Pub Date : 2026-01-15 Epub Date: 2025-09-22 DOI: 10.1016/j.expthermflusci.2025.111622

Yushuai Liu , Chuanyu Fang , Shaolin Wang , Cunxi Liu , Yong Mu , Gang Xu

Swirl cup airblast fuel injectors are critical components in modern low-emission gas turbine combustors. Understanding the underlying physics of the interaction between fuel spray and complex swirling airflow is crucial for optimizing injector performance. This study investigates the influence of Venturi outlet angles (15°, 25°, and 35°) on airflow field and spray atomization dynamics. Advanced optical diagnostics, including high-speed shadowgraph, Phase Doppler Particle Analyzer (PDPA), Particle Imaging Velocimetry (PIV), and Planar Mie scattering (PMie), were employed to quantify flow-spray interactions under controlled fuel flow rates (2.0–4.0 kg/h) and 3 % relative air pressure drop. Results demonstrate that the Venturi outlet angle significantly modulates primary atomization. Increasing the angle from 15° to 35° reduces liquid film length by 69.2 % due to enhanced gas–liquid shear stress. Moreover, larger angles amplify central toroidal recirculation zone (CTRZ) reverse velocity (−1.2 to −6.8 m/s), intensifying droplet entrainment and reducing Sauter Mean Diameter (SMD) by 30.9 %. These findings highlight that Venturi angles > 25° optimize atomization by balancing shear-driven breakup and recirculation-enhanced mixing, providing critical insights for designing fuel injectors with improved combustion stability and emission performance.

旋流杯式鼓风喷油器是现代低排放燃气轮机燃烧室的关键部件。了解燃油喷射与复杂旋转气流之间相互作用的基本物理原理对于优化喷油器性能至关重要。本文研究了文丘里出口角（15°、25°和35°）对气流场和喷雾雾化动力学的影响。采用先进的光学诊断技术，包括高速阴影成像、相位多普勒粒子分析仪（PDPA）、粒子成像测速仪（PIV）和平面米氏散射（PMie），量化控制燃油流量（2.0-4.0 kg/h）和3%相对空气压降下的流动-喷雾相互作用。结果表明，文丘里出口角对一次雾化有明显的调节作用。将夹角从15°增加到35°，由于气液剪切应力的增强，液膜长度减少了69.2%。此外，更大的角度放大了中心环形再循环区（CTRZ）的反向速度（- 1.2 ~ - 6.8 m/s），强化了液滴夹带，使井眼平均直径（SMD）减小了30.9%。这些研究结果表明，文丘里角25°通过平衡剪切驱动的破碎和再循环增强的混合来优化雾化，为设计具有更好燃烧稳定性和排放性能的喷油器提供了重要见解。

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