Experimental Thermal and Fluid Science最新文献

{"title":"Effects of hydrogen and ammonia substitution on morphological and optical parameters of soot aggregates in ethylene/air laminar coflow diffusion flames","authors":"Raul Serrano-Bayona ,&nbsp;Felipe Campuzano ,&nbsp;Faruk Aydin ,&nbsp;Tirthankar Mitra ,&nbsp;Peng Liu ,&nbsp;William L. Roberts","doi":"10.1016/j.expthermflusci.2026.111698","DOIUrl":"10.1016/j.expthermflusci.2026.111698","url":null,"abstract":"<div><div>This study investigates the morphological and optical properties of soot aggregates in ethylene/air laminar coflow diffusion flames under partial substitution by hydrogen (H₂) and ammonia (NH₃), using the non-intrusive multi-angle light scattering (MALS) technique. A vertically-polarized 514.5 nm beam was focused on the flame centerline, and the scattering signal was collected between 25°-155°. A reference flame (Fuel: 60 vol% ethylene, 40 vol% nitrogen) was compared with cases where nitrogen (N₂) is substituted with H₂ and NH₃, maintaining a constant exit flow velocity. Measurements were carried out at three heights to assess the influence of residence time. Soot properties, including scattering-to-absorption ratio (<span><math><msub><mi>ρ</mi><mrow><mi>SA</mi></mrow></msub></math></span>), single-scatter albedo (<span><math><msub><mi>ω</mi><mi>A</mi></msub></math></span>), mean aggregate radius of gyration (<span><math><msub><mi>R</mi><mrow><mi>gm</mi></mrow></msub></math></span>), fractal dimension (<span><math><msub><mi>D</mi><mi>f</mi></msub></math></span>), and primary particle diameter (<span><math><msub><mi>d</mi><mi>p</mi></msub></math></span>), were characterized using the Rayleigh-Debye-Gans theory for fractal aggregates (RDG-FA). H₂ substitution increased <span><math><msub><mi>R</mi><mrow><mi>gm</mi></mrow></msub></math></span> and <span><math><msub><mi>D</mi><mi>f</mi></msub></math></span>, and displayed a more pronounced decrease in <span><math><msub><mi>d</mi><mi>p</mi></msub></math></span>, indicating enhanced aggregation and restructuring driven by elevated temperatures. Conversely, NH₃ substitution reduced <span><math><msub><mi>R</mi><mrow><mi>gm</mi></mrow></msub></math></span>, possibly due to inhibition in soot nucleation rates and surface growth by reducing H-radical concentrations and carbon-based precursors. <span><math><msub><mi>d</mi><mi>p</mi></msub></math></span> decreased with height, possibly due to enhanced graphitization and surface oxidation. Higher flame temperature increased <span><math><msub><mi>ρ</mi><mrow><mi>SA</mi></mrow></msub></math></span> and <span><math><msub><mi>ω</mi><mi>A</mi></msub></math></span>, and these ratios decreased with a reduction in carbon flux. These results offer a more integrated understanding of the links between aggregate structure, growth dynamics, and radiative behavior of soot formed under different fuel substitution conditions.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"174 ","pages":"Article 111698"},"PeriodicalIF":3.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145941149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wind tunnel experimental study on drag reduction characteristics and mechanism of a wing with porous surface integrated with micro-blowing","authors":"Hai Du ,&nbsp;Yuhang Wei ,&nbsp;Yang Zhao ,&nbsp;Jiang Xu ,&nbsp;Dongsheng Gong ,&nbsp;Qiushi Li ,&nbsp;Yunao He","doi":"10.1016/j.expthermflusci.2026.111699","DOIUrl":"10.1016/j.expthermflusci.2026.111699","url":null,"abstract":"<div><div>Approximately 50% of the aerodynamic drag of an aircraft originates from viscous drag, within which skin-friction drag is the dominant component. Therefore, research on turbulent drag reduction holds both substantial economic value and scientific significance. In this study, the NASA SC (2)-0714 airfoil is selected as the research model, with porous media installed at the trailing edge. A combination of static force measurements and PIV experiments is employed to investigate the drag-reduction mechanism of a passive–active hybrid control strategy that integrates porous media with micro-blowing. Experimental results show that when only porous media are applied, the total drag of the airfoil decreases by 17.6% and the lift-to-drag ratio increases by 18.1%. With the addition of micro-blowing, the total drag reduction further reaches 20.1% and the lift-to-drag ratio improves by 20.8%. The local maximum drag reduction on the porous-wall surface of the airfoil reaches 33.4%, and is further enhanced to 40.2% under the influence of micro-blowing. Flow-field analysis reveals that the proposed passive–active hybrid control not only significantly reduces skin-friction drag, but also thickens the shear layer and decreases wall shear stress. Specifically, the average shear-layer thickness on the airfoil surface increases by 36.8% with porous media and further rises to 47.3% when combined with micro-blowing. In addition, this control strategy is capable of breaking up and lifting the vortex structures within the separation region, thereby substantially improving the overall aerodynamic performance.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"174 ","pages":"Article 111699"},"PeriodicalIF":3.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study on the influence of multi-row vortex generators on static hydrofoil","authors":"Pengzhong Wang ,&nbsp;Zhenyu Su ,&nbsp;Lan Ding ,&nbsp;Lu Wang ,&nbsp;Hongyang Zhao ,&nbsp;Bin Huang","doi":"10.1016/j.expthermflusci.2026.111703","DOIUrl":"10.1016/j.expthermflusci.2026.111703","url":null,"abstract":"<div><div>Vortex generators (VGs) suppress flow separation by introducing high-momentum fluid into the boundary layer, a technique that has been successfully implemented in aircraft and wind turbines. In hydraulic applications, VGs have also demonstrated effectiveness in controlling cloud cavitation. Previous research has primarily focused on single-row VG configurations, with limited studies on dual-row arrangements in wind turbines. Investigations into the effects of multi-row VGs (exceeding two rows) on flow field characteristics remain notably scarce. This study experimentally examines the cavitation and non-cavitation characteristics of a NACA63820 hydrofoil equipped with five-row micro vortex generators (mVGs), with particular emphasis on their influence on the hydrodynamic performance of stationary hydrofoils under both cavitating and non-cavitating conditions. The results reveal three key findings. First, regarding hydrodynamic torque, the multi-row mVGs exhibit negligible effects on the torque coefficient under non-cavitating conditions. However, under cavitating conditions, they significantly reduce the torque at angles of attack (AoA) below 6° compared to a smooth hydrofoil, while inducing higher torque at AoA exceeding 6°. Second, for cavitation-induced flow noise, the multi-row VGs effectively reduce the total sound pressure level (TSPL) at AoA below 6°, but substantially amplify hydrofoil-generated noise at higher AoA. Third, concerning cavitation patterns, the multi-row VGs modify the spatial distribution of surface cavitation, resulting in more uniform coverage while simultaneously increasing the frequency of cavitation shedding.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"174 ","pages":"Article 111703"},"PeriodicalIF":3.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 mechanism of vortex structure evolution in dual synthetic jets over a heating plate","authors":"Yuanyuan Liu,&nbsp;Xinyu Liang,&nbsp;Wenqiang Peng,&nbsp;Zhenbing Luo,&nbsp;Xinyu Xie,&nbsp;Xiong Deng","doi":"10.1016/j.expthermflusci.2026.111689","DOIUrl":"10.1016/j.expthermflusci.2026.111689","url":null,"abstract":"<div><div>Multiple-orifice synthetic jets have garnered significant attention in recent research due to their exceptional heat transfer performance in small installations. To achieve a larger heat dissipation area while minimizing installation height, this study employs dual synthetic jets impinging on a heated plate and investigates the influence of installation height (<em>h_i</em>/<em>w_o</em>) on the heat transfer characteristics. The heat transfer mechanisms associated with vortex structure evolution are analyzed using particle image velocimetry (PIV) and an infrared camera, thereby facilitating a deeper understanding of flow-thermal coupling behavior. It was found that <em>h_i</em>/<em>w_o</em> significantly alters the evolution of vortex structures at a nearly constant jet Reynolds number (<em>Re_j</em> ≈ 1600). The optimal heat transfer performance (<em>Nu_max</em> ≈ 136) was achieved at <em>h_i</em>/<em>w_o</em> = 2–3, balancing the unsteady benefit and near-wall flow enhancement. At this installation height, the inner primary vortex (IPV) rolls up moderately and partially merges its vorticity with <del>t</del>he wall shear layer (WSL), while secondary vortices (SVs), SV-1 and SV-2, emanate from the outer primary vortex (OPV). The appropriate vorticity distributions of SV-1 and SV-2 promote the entrainment of ambient fluid and fluctuate the WSL. The spectral analysis further substantiates the presence of unsteady benefit. Both Welch spectra and Spectral POD mode confirmed that <em>h_i</em>/<em>w_o</em> = 2–3 delivers the best coherence maintenance, indicating an overall optimal benefit from heat transfer. Conversely, an insufficient installation height (<em>h_i</em>/<em>w_o</em> = 0–1) mitigated IPV roll-up. Although higher momentum flux and periodic kinetic energy were attained near the orifice, the convective heat transfer coefficient decayed rapidly. Excessive installation height (<em>h_i</em>/<em>w_o</em> = 4) allowed complete IPV roll-up. IPV breaks down into secondary vortices before merging into the WSL, resulting in deteriorated heat transfer performance.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"174 ","pages":"Article 111689"},"PeriodicalIF":3.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145941150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mixing and combustion of methanol and ethanol high-pressure sprays","authors":"Kevin Wan ,&nbsp;Junghwa Yi ,&nbsp;Lyle Pickett ,&nbsp;Julien Manin","doi":"10.1016/j.expthermflusci.2026.111704","DOIUrl":"10.1016/j.expthermflusci.2026.111704","url":null,"abstract":"<div><div>Time-resolved liquid and vapor mixing and combustion of methanol and ethanol from high-pressure sprays are measured by employing simultaneous high-speed diffuse-back illumination extinction imaging (DBI-EI), Rayleigh scattering, and OH* chemiluminescence. The experiments are performed in a constant-volume vessel at 22.8 kg/m<span><math><msup><mrow></mrow><mrow><mn>3</mn></mrow></msup></math></span> and 800–1200 K. Methanol exhibits a longer liquid length and slightly faster vapor penetration than ethanol. Methanol liquid droplets suspected to be nanometer-scale, invisible to the DBI-EI diagnostic, are observed via scattering several millimeters downstream of the extinction-measured liquid length. On the other hand, the DBI-EI technique appears suitable for measuring ethanol liquid length at these conditions. A 1-D adiabatic jet mixing model and vapor–liquid equilibrium approximations shed insights on differences in mixing and evaporation. Methanol is shown to be the most sensitive to perturbations from equilibrium. The alcohols require relatively little mixing to approach near-stoichiometric conditions and are thus weakly sensitive to ambient oxygen levels, but fail to ignite below 1000 K ambient temperature, at least 200 K higher than needed for typical diesel-representative hydrocarbons such as n-dodecane. Instead, they require strong mixing to reach sufficient temperatures for ignition to counteract the strong evaporative cooling effects. The effect of 5% EHN is mild under these conditions, as it was estimated to lower the ignition temperature threshold by 40 K at most.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"174 ","pages":"Article 111704"},"PeriodicalIF":3.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Droplet impact dynamics of spray coated superhydrophobic metal surfaces at various inclinations","authors":"B.V.R. Sai Krishna ,&nbsp;Manas Kumar Pal","doi":"10.1016/j.expthermflusci.2026.111697","DOIUrl":"10.1016/j.expthermflusci.2026.111697","url":null,"abstract":"<div><div>The wetting dynamics and impact behavior of water droplets on super hydrophobic (SHB) surfaces play a crucial role across wide range of applications. Hence several methods are developed for manufacturing of SHB surfaces. Among them, spray coating technique is quick, efficient and cost effective. In this study, three metal substrates are modified to exhibit superhydrophobic (SHB) properties via a unique spray coating. Droplet impact dynamics are investigated on both normal and SHB surfaces at various impact velocities (0.44–0.99 m/s) and surface inclinations (0°–60°). Key parameters including sliding length, maximum spreading factor (<span><math><msub><mrow><mi>β</mi></mrow><mrow><mi>m</mi><mi>a</mi><mi>x</mi></mrow></msub></math></span>), rebound height, contact time, coefficient of restitution (CR), and droplet detachment time are systematically analyzed.</div><div>Results show a notable reduction in <span><math><msub><mrow><mi>β</mi></mrow><mrow><mi>m</mi><mi>a</mi><mi>x</mi></mrow></msub></math></span> on SHB surfaces compared to normal ones, with <span><math><msub><mrow><mi>β</mi></mrow><mrow><mi>m</mi><mi>a</mi><mi>x</mi></mrow></msub></math></span> increasing with higher impact velocity and decreasing with increasing surface inclination. Empirical correlations for <span><math><msub><mrow><mi>β</mi></mrow><mrow><mi>m</mi><mi>a</mi><mi>x</mi></mrow></msub></math></span> as a function of Weber number are developed for both surface types, achieving prediction accuracies within <span><math><mrow><mo>±</mo><mn>7</mn><mtext>%</mtext></mrow></math></span>. On SHB surfaces, droplet rebound is observed, where rebound height increases and CR decreases with increase in impact velocity. Correlations for dimensionless contact time are also proposed, with similar predictive accuracy.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"174 ","pages":"Article 111697"},"PeriodicalIF":3.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Combined effects of fine particles and surfactant on bubble and bubbly flow characteristics in a narrow rectangular column","authors":"Ryo Kurimoto ,&nbsp;Soichiro Horita ,&nbsp;Kota Haruna ,&nbsp;Kosuke Hayashi","doi":"10.1016/j.expthermflusci.2026.111702","DOIUrl":"10.1016/j.expthermflusci.2026.111702","url":null,"abstract":"<div><div>Combined effects of fine particles and surfactant on bubbles and overall bubbly flows were investigated using image processing techniques. The distribution of bubble diameter <em>d</em> in the particle-laden surfactant solution shifted to larger diameter region with increasing measurement heights <em>z</em> due to bubble coalescence and lay between that in water and that in the particle-laden water. The distribution of the bubble aspect ratio <em>E</em> in the particle-laden surfactant solution did not vary with increasing <em>z</em> in contrast to that in the surfactant solution. The surfactant concentration available for adsorption onto the bubble interface was estimated by measuring the surface tension and was much lower than the setting value in the particle-laden surfactant solution due to surfactant adsorption onto particle surfaces. Additional measurements of <em>d</em> confirmed that the estimated concentration was adequate to inhibit bubble coalescence, while being inadequate to affect <em>E</em>. The distributions of the bubble velocity and gas holdup were also measured. In the particle-laden surfactant solution, the bubble velocity decreased while the gas holdup increased compared with those in the particle-laden water. This was attributed to the ratio of large <em>d</em> bubbles.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"174 ","pages":"Article 111702"},"PeriodicalIF":3.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Refuse derived fuels: Using near-infrared spectroscopy and machine learning to predict moisture content and dry particle spectra","authors":"J. Fischer ,&nbsp;T. Kunz ,&nbsp;K. Treiber ,&nbsp;V. Scherer","doi":"10.1016/j.expthermflusci.2025.111678","DOIUrl":"10.1016/j.expthermflusci.2025.111678","url":null,"abstract":"<div><div>Refuse derived fuel (RDF) sourced from industrial and municipal waste contains primarily plastics, paper/cardboard and textiles. Since RDF has high heating values and low prices, it is used as alternative fuel to coal in cement production, offering CO₂ reductions. However, the cement industry currently lacks real-time quality control of RDF, resulting in unnoticed reductions in heating value caused by elevated moisture content. Moisture content determination by drying takes up to 4 h, which does not allow for quick reactions in operation of the cement kiln.</div><div>This study addresses the challenge by applying near-infrared spectroscopy (NIRS) to predict the moisture content of paper and cardboard particles, which retains most moisture in RDF. The particles were moisturized by different methods with NIRS measurements at each stage. For the prediction, different approaches ranging from linear regression of selected wavelength absorptions to multiple machine learning regression techniques like ridge, lasso and multilayer perceptron are compared in accuracy and feature representation. The multilayer perceptron showed accurate results and robust feature selection, although also simple linear regression at selected wavelength gave adequate accuracy.</div><div>In a second step, moisture content and spectra of wet particles were used to predict the spectra of dry particles. These spectra are essential to correctly identify particle types or predict heating values, since training data consists of dry particle data. While linear models are not reaching acceptable results, both an autoencoder and a random forest regressor yielded spectra with correct shapes, which is sufficient for classification with derivative spectra.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"173 ","pages":"Article 111678"},"PeriodicalIF":3.3,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145692293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 the atomization characteristics and influencing factors of tangential centrifugal nozzles","authors":"Changchun Liu ,&nbsp;Cheng Xu ,&nbsp;Kaiyang Wu ,&nbsp;Haoyue Xi ,&nbsp;Shijie Xin ,&nbsp;Lei Bai","doi":"10.1016/j.expthermflusci.2025.111679","DOIUrl":"10.1016/j.expthermflusci.2025.111679","url":null,"abstract":"<div><div>Understanding the atomization characteristics of tangential centrifugal nozzles is crucial for optimizing applications in combustion, fire suppression, and cooling. This study experimentally investigates the P-Q curves, droplet size distribution, spray cone angle, and velocity vector field of eight nozzles, which were experimentally measured. The calculation method of the swirl number (<em>S_n</em>) in tangential centrifugal atomizing nozzles was systematically established. The flow coefficient (<em>C_D</em>) of various nozzles and its mathematical relationship with the swirl number, inlet and outlet diameters, and Reynolds number were determined. Additionally, a dimensionless parameter (Π), characterizing the Sauter Mean Diameter (SMD), was constructed based on the Reynolds number and swirl number. Both the inlet Reynolds number (<em>Re_in</em>) and swirl intensity govern droplet size. SMD demonstrates a characteristic U-shaped dependency on Π, with minimum values occurring at 0.4 &lt; Π &lt; 1.2. Furthermore, higher pressures produce smaller SMD values. Swirl intensity significantly impacts the spray cone angle, with larger swirl numbers leading to wider angles. It was also observed that the spray cone angle produced by the nozzle is not strictly symmetrical about the outlet’s center axis but exhibits a certain offset angle. Particle Image Velocimetry (PIV) measurements revealed that droplets at higher swirl numbers (<em>S_n</em> ≥ 2.5) are predominantly concentrated on both sides of the flow field. In contrast, at lower swirl numbers (<em>S_n</em> &lt; 2.5), the flow field becomes more sensitive to pressure changes, promoting droplet accumulation in the central region of the nozzle outlet axis.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"173 ","pages":"Article 111679"},"PeriodicalIF":3.3,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145692351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A theoretical and experimental study on CCFL in a scaled-down model of a small modular reactor (SMR) hot leg","authors":"Jie Wan ,&nbsp;Xin Ma ,&nbsp;Huafa Chen ,&nbsp;Wan Sun ,&nbsp;Yang Liu ,&nbsp;Ren Liang ,&nbsp;Longxiang Zhu ,&nbsp;Luteng Zhang ,&nbsp;Qiang Lian ,&nbsp;Simiao Tang ,&nbsp;Liang-Ming Pan","doi":"10.1016/j.expthermflusci.2025.111664","DOIUrl":"10.1016/j.expthermflusci.2025.111664","url":null,"abstract":"<div><div>The Counter-Current Flow Limitation (CCFL) phenomena in horizontal and horizontal-inclined pipes have been extensively studied in the past. In recent years, small modular reactors (SMR) have attracted widespread attention as an ideal energy source for offshore development, which have a compact design with a small length-to-diameter ratio of the hot leg. Therefore, in this study, air–water CCFL visualization experiments were conducted in a scaled-down model of a SMR hot leg. The results indicated that, as the gas flow rate increases, the flow can be divided into three distinct regions: the stratified-entrainment region, the liquid-level rising region, and the liquid-level falling region, with CCFL occurring in the liquid-level rising region. A sudden decrease in the liquid penetration flow rate, which was measured by weighing method, was adopted as the criterion for the onset of CCFL, and then the CCFL characteristic curve was obtained. The mechanisms of CCFL were investigated over different ranges of liquid flow rates based on the characteristic curve and the results of the visualization experiment. Finally, a force analysis of the gas–liquid counter-current flow was performed based on the experimental results, and the momentum equations for gas and liquid phases were established to develop a CCFL prediction model. In addition, to complete the new model, several existing interfacial friction factor models were evaluated, and a modified interfacial friction factor model was developed.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"173 ","pages":"Article 111664"},"PeriodicalIF":3.3,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145623449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}