Experimental Thermal and Fluid Science最新文献

{"title":"Splashing of impacting droplets on an artificial superhydrophobic surface: Effect of viscosity in hole-nucleation process","authors":"Kumar Gaurav ,&nbsp;Visakh Vaikuntanathan ,&nbsp;Sivakumar Deivandren","doi":"10.1016/j.expthermflusci.2025.111682","DOIUrl":"10.1016/j.expthermflusci.2025.111682","url":null,"abstract":"<div><div>The present study reports an experimental investigation on splashing of liquid droplets impacting on an artificial superhydrophobic (SHP) surface prepared by coating NeverWet hydrophobic solution. The prepared SHP surface exhibits micro-bumps decorated with nano-structures, as seen in Scanning Electron Microscopy (SEM) images and surface profilometry. The presence of micro-bumps causes the fragmentation of spreading lamella via hole-nucleation process, leading to a significant reduction in droplet contact time as shown in a recent study reported in the literature. The focus of the current study is on the effect of droplet viscosity on the hole-nucleation and contact time of impacting droplets. The experiments with droplet impact velocity, <span><math><msub><mrow><mi>U</mi></mrow><mrow><mi>o</mi></mrow></msub></math></span> ranging from 0.3 m/s to 3.6 m/s are conducted using three different droplet liquids – water (W), 20% glycerine and 80% water (G20), and 50% glycerine and 50% water (G50) – varying mainly in their dynamic viscosity. From high-speed videos of droplet impact dynamics, the various impact regimes are first identified and mapped in <span><math><mrow><mi>W</mi><mi>e</mi></mrow></math></span> (droplet Weber number) – <span><math><mrow><mi>R</mi><mi>e</mi></mrow></math></span> (droplet Reynolds number) plane for all three droplet liquids. Quantitative measurements of the temporal variation of lamella diameter, number of holes formed, time at which the first hole nucleates, critical impact velocity at which the hole-nucleation begins, and contact time are extracted. These measurements clearly show that the contact time reduction of splashing droplets decreases with increase in droplet viscosity. Moreover, the number of holes formed in the lamella film scales with the number of micro-bumps underneath the droplet at its maximum spreading which, in turn, decreases with increase in droplet viscosity. The time instant at which the first hole nucleates on the lamella film is seen to be independent of the droplet viscosity. A modified model is proposed to describe the effects of droplet viscosity and surface micro-characteristics (height and pitch of surface micro-bumps) on the critical velocity for hole nucleation, <span><math><msub><mrow><mi>U</mi></mrow><mrow><mi>c</mi><mo>,</mo><mi>h</mi></mrow></msub></math></span>. The predictions from this modified model seem to explain the experimental observations on <span><math><msub><mrow><mi>U</mi></mrow><mrow><mi>c</mi><mo>,</mo><mi>h</mi></mrow></msub></math></span> in the current study as well as in the literature.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"173 ","pages":"Article 111682"},"PeriodicalIF":3.3,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797531","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":"Dynamics of bursting droplets from surfacing bubble plumes","authors":"Jitae Do ,&nbsp;Binbin Wang","doi":"10.1016/j.expthermflusci.2025.111680","DOIUrl":"10.1016/j.expthermflusci.2025.111680","url":null,"abstract":"<div><div>The dynamics of bursting droplets from surface bubbles is an important mechanism for water-to-air transport of small particles and contaminants. We investigated bubble-bursting droplets from bubble plumes, released from an air stone (AS) or a single nozzle (SN) at four gas flow rates ranging from 0.1 to 0.8 L min⁻¹. Quantitative imaging was used to analyze the statistics of size and velocity distributions for rising bubbles and droplets ejected by bursting bubbles. Significantly greater droplet number, mass flow rate, and median size were observed in AS, by factors of 20, 8.6, and 1.8 compared to SN, reflecting the influence of subsurface bubble characteristics on droplet production. Log-normal distributions fit well to droplet size and velocity distribution regardless of the release mechanism. The characteristic median sizes show a bubble–droplet relationship of <span><math><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>∼</mo><msubsup><mrow><mi>R</mi></mrow><mrow><mi>b</mi></mrow><mrow><mn>1</mn><mo>.</mo><mn>4</mn></mrow></msubsup></mrow></math></span>, which implies Bond number relationship of <span><math><mrow><mi>B</mi><msub><mrow><mi>o</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>∼</mo><mi>B</mi><msubsup><mrow><mi>o</mi></mrow><mrow><mi>b</mi></mrow><mrow><mn>1</mn><mo>.</mo><mn>4</mn></mrow></msubsup></mrow></math></span> under constant fluid properties. Scaling analysis using visco-capillary length and capillary velocity shows <span><math><mrow><mi>L</mi><msub><mrow><mi>a</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>∼</mo><mi>C</mi><msubsup><mrow><mi>a</mi></mrow><mrow><mi>d</mi></mrow><mrow><mo>−</mo><mn>1</mn><mo>.</mo><mn>4</mn></mrow></msubsup></mrow></math></span>, suggesting a universal scaling relationship for bursting droplets from surfacing of single bubble and bubble plumes. Involving both length and velocity scales of bubbles and droplets shows <span><math><mrow><mi>F</mi><msub><mrow><mi>r</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>∼</mo><msup><mrow><mrow><mo>(</mo><mi>B</mi><msub><mrow><mi>o</mi></mrow><mrow><mi>b</mi></mrow></msub><mi>W</mi><msub><mrow><mi>e</mi></mrow><mrow><mi>b</mi></mrow></msub><mo>)</mo></mrow></mrow><mrow><mo>−</mo><mn>0</mn><mo>.</mo><mn>3</mn></mrow></msup></mrow></math></span>, a scaling relationship potentially used for predicting droplet dynamics from bursting bubble plumes. These findings provide the first quantitative scaling linking bubble plume and bursting droplet dynamics, with potential applications in aerosol generation, wastewater aeration, and ocean–atmosphere mass-exchange studies.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"173 ","pages":"Article 111680"},"PeriodicalIF":3.3,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797532","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":"Consecutive water entries of two side-by-side spheres: cavity interference and surface closure characteristics","authors":"Xu Wang ,&nbsp;Xujian Lyu ,&nbsp;Hui Tang ,&nbsp;Chao Qi ,&nbsp;Ruisheng Sun","doi":"10.1016/j.expthermflusci.2025.111684","DOIUrl":"10.1016/j.expthermflusci.2025.111684","url":null,"abstract":"<div><div>This paper presents an experimental investigation into cavity interference and surface closure characteristics of two side-by-side spheres undergoing consecutive water entries. A high-speed imaging system was employed to capture the dynamic processes of the two cavities, including the cavity elongation and their interaction with the free surface during the closure stage. Four distinct interference modes—rebound, expansion, tail, and bubble-dominated—are found primarily depending on the time interval between the two water entries, <span><math><mi>Δ</mi></math></span><em>t</em>, while showing little sensitivity to the lateral distance. Unlike the single-cavity closure, the following cavity, subject to interference, undergoes two separate detachment events from the free surface, characterized by a closure angle (defined as the acute angle between the cavity tail-end face and the free surface) whose magnitude and orientation scale with <span><math><mi>Δ</mi></math></span><em>t</em>. Statistical analysis indicates that the initial detachment time is independent of the adjacent cavity’s evolution, whereas the emergence of a closure angle significantly prolongs the complete detachment time and increases cavity length, especially at smaller lateral distances.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"173 ","pages":"Article 111684"},"PeriodicalIF":3.3,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797530","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":"Collisions between droplets of liquids of different viscosity and composite fuel particles","authors":"Anastasia Islamova,&nbsp;Pavel Tkachenko,&nbsp;Nikita Shlegel,&nbsp;Stanislav Shulyaev,&nbsp;Pavel Strizhak","doi":"10.1016/j.expthermflusci.2025.111669","DOIUrl":"10.1016/j.expthermflusci.2025.111669","url":null,"abstract":"<div><div>It is important to understand the physics of liquid droplet collisions for a variety of applications ranging from inkjet printing to composite fuel combustion. The use of composite fuels is associated with some challenges and limitations. It is necessary to study the collisions of droplets and particles used as slurry fuel components. The selected objects of research were water and oil droplets, as well as particles of pine, cedar, coal and filter cake. Typical collision regimes (agglomeration and destruction) were identified. The characteristics of child droplets and conditions of their interaction with droplets and particles were determined. Differences between the characteristics of interaction of combustible and noncombustible component droplets with particles were detected. Equations were presented for a mathematical description of transition boundaries between regimes on maps taking account of the dimensionless linear impact parameter, the Weber number and the Ohnesorge number. The decisive factor for agglomeration or separation of droplets and particles was the properties of liquid. If a particle was pre-wetted, the type and condition of its surface did not have a significant effect on interaction regimes. The occurrence of a regime was also found to depend on the particle shape. A comparison of interaction regime maps for liquid droplets and biomass particles in the experiments with water and motor oil revealed that the separation boundary for oil shifted towards 18–27 % higher Weber numbers. This is accounted for by the physical properties of the investigated liquids. Guidelines on using the research findings in the development of secondary atomization technologies of fuel droplets were provided.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"173 ","pages":"Article 111669"},"PeriodicalIF":3.3,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748348","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":"Intermittent two-phase flow characterization using advanced diagnostics in a high-pressure large-diameter slightly upward inclined pipe","authors":"Ahmed Aql ,&nbsp;E. Al-Safran ,&nbsp;E. Pereyra ,&nbsp;C. Sarica","doi":"10.1016/j.expthermflusci.2025.111683","DOIUrl":"10.1016/j.expthermflusci.2025.111683","url":null,"abstract":"<div><div>This study experimentally investigates slug flow characteristics under high-pressure conditions of 2.76 MPa (400 psi) in a 2° upward-inclined, large ID pipe with an internal diameter of 156 mm (6.1 in.), using advanced diagnostic instruments, including high-resolution wire-mesh sensors and a high-speed visualization system. The tests are performed within a broad range of superficial liquid and gas velocities of <em>v_SL</em> = 0.01–0.35 m/s, and <em>v_SG</em> = 1.3–2.5 m/s, allowing investigation of operational and topological features, such as film reversal and interfacial roughness, and enabling the distinction between slug and pseudo-slug flow. It is found that the strength of the hydraulic seal in the flow structure (slug and pseudo-slug) body governs the characteristics of the intermittent flow. In addition, the superficial liquid velocity <em>v_SL</em> is found to be the major contributor to the formation and stability of the hydraulic seal, followed by the superficial gas velocity <em>v_SG</em>. Specifically, the mean slug length, <em>L_S,</em> and slug frequency, <em>f_S</em>, are significantly influenced by superficial liquid velocity. For example, increasing <em>v_SL</em> promotes longer and more frequent slugs, while the impact of superficial gas velocity on slug flow characteristics depends on the structure body liquid holdup, and hydraulic seal integrity. Overall, superficial gas velocity predominantly decreases liquid holdup in slug and film regions, due to high interfacial shear stress and film thinning.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"173 ","pages":"Article 111683"},"PeriodicalIF":3.3,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145836376","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":"Drag estimation for isolated, surface-mounted, droplet-inspired geometries and the effect of boundary layer parameters on flow development","authors":"Xueqing Zhang,&nbsp;Burak A. Tuna,&nbsp;Serhiy Yarusevych,&nbsp;Sean D. Peterson","doi":"10.1016/j.expthermflusci.2025.111662","DOIUrl":"10.1016/j.expthermflusci.2025.111662","url":null,"abstract":"<div><div>This study investigates flow development over three-dimensional droplet-inspired models submerged in a boundary layer using particle image velocimetry (PIV). Aerodynamic drag is estimated from stereoscopic PIV measurements performed in multiple planes in a laminar boundary layer regime for a Reynolds number based on obstacle height of <span><math><mrow><msub><mrow><mi>Re</mi></mrow><mrow><mi>h</mi></mrow></msub><mo>≈</mo><mn>2070</mn></mrow></math></span> and a relative droplet submergence in the boundary layer of <span><math><mrow><mi>δ</mi><mo>/</mo><mi>h</mi><mo>=</mo><mn>1</mn><mo>.</mo><mn>0</mn></mrow></math></span>. Three geometries are considered: a sessile droplet, a droplet on the verge of runback (depinning), and a hemisphere for baseline comparison with prior studies. The drag coefficients of the sessile and runback models are <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mi>D</mi></mrow></msub><mo>≈</mo><mn>0</mn><mo>.</mo><mn>33</mn></mrow></math></span> and 0.35, respectively. Although the difference in drag coefficients between the two droplet configurations is modest, the runback model demonstrates a reduction in drag force proportional to its reduced frontal area. The effects of relative submergence and boundary layer regime on flow development and wake dynamics are further examined at <span><math><mrow><mi>δ</mi><mo>/</mo><mi>h</mi><mo>=</mo><mn>1</mn><mo>.</mo><mn>0</mn></mrow></math></span> and 1.4 for laminar boundary layers, and <span><math><mrow><mi>δ</mi><mo>/</mo><mi>h</mi><mo>=</mo><mn>1</mn><mo>.</mo><mn>5</mn></mrow></math></span>, 2.0, and 3.5 for turbulent boundary layers based on time-resolved PIV measurements in the symmetry plane of the models. The results reveal notable effect of model submergence on the wake topology and dynamics. A turbulent incoming boundary layer delays separation from the protuberance in comparison with laminar flow conditions, thus altering the wake dynamics. Spectral and modal analysis using proper orthogonal decomposition provides further insight into the attendant dominant coherent structures and the associated dynamic loading and response of the droplets close to depinning conditions.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"172 ","pages":"Article 111662"},"PeriodicalIF":3.3,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145621052","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":"Orthographic high-speed visible emission imaging of plasma jet dynamics","authors":"Roberto Pio Puttini ,&nbsp;Lorenzo Capponi ,&nbsp;Massimo Franco ,&nbsp;Edward Mansfield ,&nbsp;Daniel J. Bodony ,&nbsp;Gregory S. Elliott ,&nbsp;Gianluca Rossi ,&nbsp;Francesco Panerai","doi":"10.1016/j.expthermflusci.2025.111652","DOIUrl":"10.1016/j.expthermflusci.2025.111652","url":null,"abstract":"<div><div>High-enthalpy plasma jets exhibit complex, unsteady flow behavior that is critical to the development of thermal protection systems and validation of multiphysics models for non-equilibrium flow and material response. Irradiance-based diagnostics provide high-resolution spatial and temporal characterizations, enabling visualization of flow structures, temperature estimation, and instability detection. This study investigates the dynamics of an inductively coupled plasma jet, focusing on the effects of mass flow rate, torch power, and reactor pressure on jet morphology and radiative energy distribution. Using a multi-view diagnostic system based on two synchronized, orthogonal high-speed cameras, the jet behavior is resolved in space and time. The results show that increasing flow rate produces broader, less organized jet structures, while torch power and pressure strongly influence the spatial distribution of radiative energy.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"172 ","pages":"Article 111652"},"PeriodicalIF":3.3,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145463926","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":"Analysis of scour dynamics and turbulence structures at a sequence of repelling spur dikes using higher-order moments, turbulent kinetic energy fluxes, and quadrant analysis","authors":"Sandeep Kumar,&nbsp;Prashanth Reddy Hanmaiahgari","doi":"10.1016/j.expthermflusci.2025.111637","DOIUrl":"10.1016/j.expthermflusci.2025.111637","url":null,"abstract":"<div><div>This study aims to understand local scour dynamics and turbulence characteristics around the head of repelling spur dikes by analyzing sediment bed morphology, higher-order turbulence statistics, turbulent kinetic energy fluxes, and quadrant-based turbulence events, which remain insufficiently understood in the context of these river training structures. The flow field was measured using Vectrino ADV under two Reynolds numbers (<span><math><msub><mtext>R</mtext><mtext>e</mtext></msub></math></span>) of 48,508 and 42579. The sediment bed topography exhibited distinct patterns, with maximum scour depth (<span><math><mrow><msub><mtext>d</mtext><mtext>s</mtext></msub><mrow><mo>)</mo></mrow></mrow></math></span> of 0.48 <em>h</em> (<span><math><mrow><mi>h</mi><mo>=</mo><mtext>flow depth</mtext></mrow></math></span>) and 0.55 <em>h</em> at the first spur dike in both scenarios, and at the second spur dike, greater erosion occurred at a higher Reynolds number. Higher-order turbulence moments <span><math><mrow><msub><mtext>M</mtext><mtext>12</mtext></msub><mtext>,</mtext><mspace></mspace><msub><mtext>M</mtext><mtext>21</mtext></msub><mtext>,</mtext><mspace></mspace><msub><mtext>M</mtext><mtext>30</mtext></msub></mrow></math></span> and <span><math><msub><mtext>M</mtext><mtext>03</mtext></msub></math></span>revealed ejections followed by primarily sweep, outward, and inward events near the bed. The<span><math><msub><mtext>M</mtext><mtext>03</mtext></msub></math></span> magnitude exhibited greater variation primarily with ejection events; these phenomena were shaped by bed morphology. At both Reynolds numbers, the sweep events dominate ejection events at first and second spur dikes near-bed zone. In contrast, inward and outward events prevailed at the third spur dike. Turbulent kinetic energy flux, <span><math><msub><mtext>F</mtext><mtext>ku</mtext></msub></math></span> and <span><math><msub><mtext>F</mtext><mtext>kw</mtext></msub></math></span> revealed greater magnitudes at the first and second spur dikes with dissimilarity in their sign. A significantly high vorticity is observed immediately u/s and d/s of the first spur dike throughout the depth. Quadrant analysis confirmed energetic activity near the bed zone dominated by sweep and ejection events governed turbulence structures, while the coherent structure near the water surface persisted throughout the test reach but weakened in the downstream.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"172 ","pages":"Article 111637"},"PeriodicalIF":3.3,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145414504","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":"Analysis of non-reacting and reacting flows in biogas/methane cofiring within a double-swirl burner: role of the inner swirler","authors":"Ahmed M. Abdulnaim ,&nbsp;Ahmed H. Elkholy ,&nbsp;Mohamed Elmously ,&nbsp;Hany A. Moneib ,&nbsp;Ayman M. Elbaz","doi":"10.1016/j.expthermflusci.2025.111654","DOIUrl":"10.1016/j.expthermflusci.2025.111654","url":null,"abstract":"<div><div>Environmental concerns, particularly greenhouse gas emissions, have intensified interest in renewable fuels such as biogas. However, the low reactivity of biogas presents challenges for achieving stable and efficient combustion. This study investigates the impact of inner swirl intensity on both the aerodynamic and thermal characteristics of biogas–methane cofiring in a concentric double-swirl burner. First, the influence of swirl intensity on non-reacting and reacting flow fields is analyzed using two-dimensional Particle Image Velocimetry (PIV). The study then extends to examine the effects on flame temperature distribution and exhaust emissions. Slightly rich premixed biogas/air mixtures were introduced through the inner swirl, while lean methane/air mixtures were supplied via the outer swirl. The outer swirl number was fixed at S_out = 0.49, while the inner swirl number S_in was varied (0.41, 0.72, and 1.24). Results show that increasing S_in enhances mixing and strengthens jet-to-jet interactions. A central recirculation zone (CRZ) consistently forms under all conditions, with additional outer recirculation zones appearing in non-reacting flows. In reacting cases, higher S_in reduces CRZ width while accelerating flow within it. Increased shear and vorticity at the inner shear layer enhance turbulence and sustain velocity fluctuations downstream, promoting faster mixing between fresh reactants and recirculated hot gases. Flame heat release induces radial expansion of the swirling flow and elevates turbulence intensity (V_rms), further improving mixing. These effects collectively enhance combustion efficiency, broaden the temperature field, and lead to significant reductions in CO and NO emissions. The findings highlight the effectiveness of double-swirl burners in improving biogas combustion performance and reducing their environmental impact.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"172 ","pages":"Article 111654"},"PeriodicalIF":3.3,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145577031","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":"Study on the de-icing performance of wind turbine blades based on PCMS-C14 coating combined with electrothermal heating","authors":"Zheng Sun ,&nbsp;He Shen ,&nbsp;Yiting Wang ,&nbsp;Haotian Zheng ,&nbsp;Fang Feng ,&nbsp;Yan Li","doi":"10.1016/j.expthermflusci.2025.111639","DOIUrl":"10.1016/j.expthermflusci.2025.111639","url":null,"abstract":"<div><div>Icing on wind turbine blades severely compromises turbine operation, while existing standalone anti-icing and de-icing methods exhibit inherent limitations. This study experimentally investigates the synergistic de-icing performance of wind turbine blades using the PCMS-C14 phase-change microcapsule coating, developed independently by the Wind Energy Laboratory at Northeast Agricultural University, combined with electrothermal heating. Experiments were conducted in an icing wind tunnel under controlled parameters: water flow rate (60 mL/min), ambient temperatures (−5 °C, −10 °C, −15 °C), incoming wind speeds (3 m/s, 6 m/s, 9 m/s), and energy flux densities (8 kW/m², 10 kW/m², 12 kW/m²). Results demonstrate that although higher wind speeds and lower temperatures increase de-icing energy demand, the hybrid coating-electrothermal approach significantly outperforms pure electrothermal de-icing across all tested scenarios: the highest energy-saving efficiency of 19.23 % was achieved at an energy flux density of 10 kW/m²; an energy reduction of 21.5 % was observed at an ambient temperature of −10 °C; and the optimal energy-saving effect was obtained at a wind speed of 6 m/s. This integrated strategy effectively reduces de-icing time by 25–68 s, lowers energy consumption by 12.89 % to 21.5 %, and significantly improves de-icing uniformity and thermal management stability. This study provides a practical solution and experimental basis for enhancing the energy efficiency and operational reliability of wind turbines in cold regions.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"172 ","pages":"Article 111639"},"PeriodicalIF":3.3,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145464371","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}