Experimental Thermal and Fluid Science最新文献

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Experimental Characterization of non-isothermal sloshing in microgravity 微重力条件下非等温晃动的实验表征
IF 2.8 2区 工程技术
Experimental Thermal and Fluid Science Pub Date : 2025-03-22 DOI: 10.1016/j.expthermflusci.2025.111473
F. Monteiro , P.A. Marques , A. Simonini , L. Carbonnelle , M.A. Méndez
{"title":"Experimental Characterization of non-isothermal sloshing in microgravity","authors":"F. Monteiro ,&nbsp;P.A. Marques ,&nbsp;A. Simonini ,&nbsp;L. Carbonnelle ,&nbsp;M.A. Méndez","doi":"10.1016/j.expthermflusci.2025.111473","DOIUrl":"10.1016/j.expthermflusci.2025.111473","url":null,"abstract":"<div><div>Sloshing of cryogenic liquid propellants can significantly impact a spacecraft’s mission safety and performance by unpredictably altering the center of mass and producing large pressure fluctuations due to the increased heat and mass transfer within the tanks. This study, conducted as part of the NT-SPARGE (Non-isoThermal Sloshing PARabolic FliGht Experiment) project, provides a detailed experimental investigation of the thermodynamic evolution of a partially filled upright cylindrical tank undergoing non-isothermal sloshing in microgravity. Sloshing was induced by a step reduction in gravity during the 83<span><math><mtext>rd</mtext></math></span> European Space Agency (ESA) parabolic flight, resulting in a chaotic reorientation of the free surface under inertia-dominated conditions. To investigate the impact of heat and mass transfer on the sloshing dynamics, two identical test cells operating with a representative fluid, HFE-7000, in single-species were considered simultaneously. One cell was maintained in isothermal conditions, while the other started with initially thermally stratified conditions. Flow visualization, pressure, and temperature measurements were acquired for both cells. The results highlight the impact of thermal mixing on liquid dynamics coupled with the significant pressure and temperature fluctuations produced by the destratification. The comprehensive experimental data gathered provide a unique opportunity to validate numerical simulations and simplified models for non-isothermal sloshing in microgravity, thus contributing to improved cryogenic fluid management technologies.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"166 ","pages":"Article 111473"},"PeriodicalIF":2.8,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143696891","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}
引用次数: 0
Impact of physical properties of coal slurry droplets on their interaction with coal particles 煤浆液滴物理性质对其与煤颗粒相互作用的影响
IF 2.8 2区 工程技术
Experimental Thermal and Fluid Science Pub Date : 2025-03-21 DOI: 10.1016/j.expthermflusci.2025.111478
Anastasia Islamova, Nikita Shlegel, Pavel Strizhak
{"title":"Impact of physical properties of coal slurry droplets on their interaction with coal particles","authors":"Anastasia Islamova,&nbsp;Nikita Shlegel,&nbsp;Pavel Strizhak","doi":"10.1016/j.expthermflusci.2025.111478","DOIUrl":"10.1016/j.expthermflusci.2025.111478","url":null,"abstract":"<div><div>The use of alternative slurry fuels is a well-known approach to reducing hazardous emissions during combustion without a significant decrease in efficiency. Very little is currently known about the behavior of fuel droplets colliding with wall and with each other.<!--> <!-->It is important to understand these collisions to predict the processes characteristics during the spraying and subsequent combustion of a slurry fuel in a boiler furnace. Experiments into the collisions characteristics of coal-water slurry droplets were conducted, when varying the viscosity, density and surface tension of the slurry containing different sizes solid coal particles. The rheological characteristics of the slurry were varied by using such additives as transformer oil, neonol, emulsifier D<sub>c</sub>D, Tween-20 and Tween-80. The use of surfactants was found to reduce the critical resultant velocity of a droplet sufficient for its breakup. The obtained data were compared with earlier findings. It was established that the fuel compositions are non-Newtonian fluids that demonstrate different secondary atomization characteristics. Nevertheless, droplet-particle interaction regimes tended to be very similar, which is accounted for by inhomogeneity of liquids. A chart was also produced to illustrate the use of identified specific aspects of interaction of slurry droplets with solid particles in thermal engineering applications.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"166 ","pages":"Article 111478"},"PeriodicalIF":2.8,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143681832","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}
引用次数: 0
GDI spray wall impingement against a heated and instrumented wall GDI喷淋壁对加热和仪表化壁的冲击
IF 2.8 2区 工程技术
Experimental Thermal and Fluid Science Pub Date : 2025-03-19 DOI: 10.1016/j.expthermflusci.2025.111475
Raúl Payri, Francisco Javier Salvador, Jaime Gimeno, César Carvallo
{"title":"GDI spray wall impingement against a heated and instrumented wall","authors":"Raúl Payri,&nbsp;Francisco Javier Salvador,&nbsp;Jaime Gimeno,&nbsp;César Carvallo","doi":"10.1016/j.expthermflusci.2025.111475","DOIUrl":"10.1016/j.expthermflusci.2025.111475","url":null,"abstract":"<div><div>Spray–wall interaction (SWI) is critical in the atomization, mixing, and combustion behavior of fuels and the formation of pollutant emissions. These elusive effects impact internal combustion engine performance and other engineering applications such as spray-induced cooling, painting, and solid deposit control. As a result, spray wall interactions are an active area of research. This article aims to use a thermoregulated steel wall to study the spray–wall interaction phenomenon. A multi-hole injector manufactured by Continental was used. Isooctane was employed as the injected fuel, and the wall was positioned at one distance from the injector tip and one inclination angle, changing the wall surface temperature, the injection pressure, the ambient back pressure, the ambient temperature, and the fuel temperature. The spray–wall heat transfer is analyzed, and the heat flux is measured by employing high-speed thermocouples fitted in the wall and using a one-dimensional transient wall heat model. The ambient and wall temperatures highly affect the amount of liquid in the spray. By increasing both temperatures, a lesser amount of liquid was found. For the range evaluated in the experimental campaign, the results revealed a significant increase in surface heat flow and wall temperature variance with both wall and fuel temperatures and the ambient temperature, but to a lesser extent.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"166 ","pages":"Article 111475"},"PeriodicalIF":2.8,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143705862","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}
引用次数: 0
Experimental study on flow regime classification and riser pressure fluctuation characteristics in the long-distance pipeline S-shaped riser system 长输管道s型立管系统流型分类及立管压力波动特性试验研究
IF 2.8 2区 工程技术
Experimental Thermal and Fluid Science Pub Date : 2025-03-12 DOI: 10.1016/j.expthermflusci.2025.111467
Yeqi Cao , Qiang Xu , Yuwen Li , Bo Huang , Haiyang Yu , Liejin Guo
{"title":"Experimental study on flow regime classification and riser pressure fluctuation characteristics in the long-distance pipeline S-shaped riser system","authors":"Yeqi Cao ,&nbsp;Qiang Xu ,&nbsp;Yuwen Li ,&nbsp;Bo Huang ,&nbsp;Haiyang Yu ,&nbsp;Liejin Guo","doi":"10.1016/j.expthermflusci.2025.111467","DOIUrl":"10.1016/j.expthermflusci.2025.111467","url":null,"abstract":"<div><div>Flow instability in the pipeline-riser is closely related to the fluctuation frequency and amplitude characteristics of the riser’s differential pressure. The gas–liquid overall and local flow regime distribution and flow characteristics in the long-distance pipeline S-shaped riser system with 46 mm ID and 1722 m length are investigated. An overall flow regime classification method based on the time-domain features, probability density distribution and power spectrum distribution of the riser’s differential pressure signal is proposed. The overall flow regimes SS, OSC, and ST1 at lower gas velocities (<em>V<sub>SG</sub></em><sub>0</sub> &lt; 3.00 m/s) correspond to riser’s local flow regimes that exhibit a composite morphology of multiple single flow regimes in the vertical upward pipe, whereas the overall flow regime ST2 at higher gas velocities (<em>V<sub>SG</sub></em><sub>0</sub> ≥ 3.00 m/s) shows the same single flow regime as that in the vertical upward pipe. Based on the gas phase Strouhal number and the no-slip liquid volume fraction, a correlation for predicting the fluctuation frequency of riser’s differential pressure is established. The fluctuation amplitude, minimum, maximum and asymmetry along the mean value of the riser’s differential pressure are associated with the overall flow regime, and a quantitative division criterion is proposed for predicting the unstable flow in the long-distance pipeline-riser system.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"166 ","pages":"Article 111467"},"PeriodicalIF":2.8,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143681879","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}
引用次数: 0
Experimental study on the effects of transverse standing wave frequency and amplitude on oscillation and mode transition of partially premixed flame 横驻波频率和振幅对部分预混火焰振荡和模态转变影响的实验研究
IF 2.8 2区 工程技术
Experimental Thermal and Fluid Science Pub Date : 2025-03-12 DOI: 10.1016/j.expthermflusci.2025.111477
Yue Lou , Shoujun Ren , Yikai Li , Ziming Yang , Haiyan Chen , Jiajia Lin
{"title":"Experimental study on the effects of transverse standing wave frequency and amplitude on oscillation and mode transition of partially premixed flame","authors":"Yue Lou ,&nbsp;Shoujun Ren ,&nbsp;Yikai Li ,&nbsp;Ziming Yang ,&nbsp;Haiyan Chen ,&nbsp;Jiajia Lin","doi":"10.1016/j.expthermflusci.2025.111477","DOIUrl":"10.1016/j.expthermflusci.2025.111477","url":null,"abstract":"<div><div>Reasonable matching of the acoustic and the combustion field can effectively boost burner power density. This study investigates the oscillation modes of the flame and the mechanism of mode transition under periodic acoustic excitation at different frequencies and amplitudes. Visualize the reaction zone by capturing OH* chemiluminescence images with a 307.15 nm filter and an ICCD camera. The intensity fluctuation of OH* and modal transitions of flame are analyzed using Fast Fourier Transform (FFT) and Proper Orthogonal Decomposition (POD) methods. The results show that flame disturbances from transverse standing waves depend on both the strength and duration of the acoustic field. A displacement oscillation factor (<em>p</em>*/<em>St</em><sup>2</sup>) is used to describe how the acoustic field affects the flame front. When <em>p</em>*/<em>St</em>2 is low, the acoustic field causes small-amplitude transverse symmetrical oscillations at the flame’s edges. As <em>p</em>*/<em>St</em><sup>2</sup> increases, vertical oscillations appear at the flame head, and the oscillation frequency of the flame matches the excitation frequency. High-intensity OH* chemiluminescence region is observed near the oscillation center. When <em>p</em>*/<em>St</em><sup>2</sup> is excessive, the acoustic excitation creates macro flow that causes the flame into transverse oscillation, causing local blowout, periodic disruption, and a decrease in OH* intensity. The flame heat release intensity, indicated by OH* brightness, peaks near the condition of flame mode transitions from vertical to transverse oscillation.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"166 ","pages":"Article 111477"},"PeriodicalIF":2.8,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143637270","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}
引用次数: 0
Influence of the side ratio and main longitudinal beam shape on vortex-induced vibration and aerodynamic force characteristics of Π-shaped composite girders 边比和主梁纵形对Π-shaped组合梁涡激振动及气动力特性的影响
IF 2.8 2区 工程技术
Experimental Thermal and Fluid Science Pub Date : 2025-03-11 DOI: 10.1016/j.expthermflusci.2025.111474
Kaiwen Li , Yifei Sun , Qingkuan Liu , Binxuan Wang , Qingcai Wang , Heng Cao
{"title":"Influence of the side ratio and main longitudinal beam shape on vortex-induced vibration and aerodynamic force characteristics of Π-shaped composite girders","authors":"Kaiwen Li ,&nbsp;Yifei Sun ,&nbsp;Qingkuan Liu ,&nbsp;Binxuan Wang ,&nbsp;Qingcai Wang ,&nbsp;Heng Cao","doi":"10.1016/j.expthermflusci.2025.111474","DOIUrl":"10.1016/j.expthermflusci.2025.111474","url":null,"abstract":"<div><div>Π-shaped composite girders in long-span bridges are prone to vortex-induced vibrations (VIVs). Therefore, it is important to study their VIV characteristics and corresponding countermeasures. In the present study, the effects of the side ratio (<em>B</em>/<em>H</em> = 7.00–14.00, where <em>B</em> and <em>H</em> represent the width and height of the girder, respectively), the bottom plate width of the main longitudinal beam (<em>b</em> = 0.30<em>H</em>–1.50<em>H</em>), and the inclination angle (<em>β</em> = -20°–30°) on VIVs, aerodynamic characteristics, and flow patterns were comprehensively compared. Additionally, the mechanisms underlying VIV suppression were preliminarily explored. The results indicate that the side ratio and the shape of the main longitudinal beam of the Π-shaped composite girder significantly affect the VIVs. However, the influence patterns differ and are highly related to the wind attack angle and vibration mode (vertical and torsional). The distribution patterns and values of the mean and fluctuating pressure coefficients on the upper and lower surfaces of the Π-shaped composite girder are different. These are notably influenced by the side ratio and <em>β</em> but are almost unaffected by <em>b</em>. VIVs are typically suppressed when the surface pressure frequency distribution becomes scattered and the pressure amplitude spectrum shows no distinct dominant frequency. Additionally, A reduction in the size of surface vortices is beneficial for controlling vertical VIVs. However, when the vortices are concentrated at the front of the model, they will induce torsional VIV. Within the studied parameter range, the optimal parameter combination for suppressing VIVs is <em>B</em>/<em>H</em> = 10.00, <em>b</em> ≥ 1.00<em>H</em>, and <em>β</em> = 10°. In general, practical engineering applications should consider specific conditions, such as the characteristics of the incoming flow.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"166 ","pages":"Article 111474"},"PeriodicalIF":2.8,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143620301","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}
引用次数: 0
Experimental analysis of a passive flow control structure within a turbulent boundary layer using particle image velocimetry 紊流边界层内被动流动控制结构的粒子图像测速实验分析
IF 2.8 2区 工程技术
Experimental Thermal and Fluid Science Pub Date : 2025-03-10 DOI: 10.1016/j.expthermflusci.2025.111471
Tyler Moore, Wen Wu, Taiho Yeom
{"title":"Experimental analysis of a passive flow control structure within a turbulent boundary layer using particle image velocimetry","authors":"Tyler Moore,&nbsp;Wen Wu,&nbsp;Taiho Yeom","doi":"10.1016/j.expthermflusci.2025.111471","DOIUrl":"10.1016/j.expthermflusci.2025.111471","url":null,"abstract":"<div><div>In this study, turbulent statistics over a novel additive surface structure are explored within turbulent channel flow at friction Reynolds number <em>Re</em><sub>τ</sub> ≈ 380. Experimental data is gathered in a purpose-built 3D-printed wind channel which allows for 2D Particle Image Velocimetry. The Multi Jet Fusion 3D-printed additive structure, consisting of two side walls and a top wall, is analyzed for its flow control capabilities. Potential desirable flow control outputs include localized flow acceleration, deceleration, and vortex generation. The proposed structure is configurable by manipulating the structure’s height and the angle of attack of the side and top walls. Heights of 3, 4, 6, and 7 mm of the structure are investigated, ranging from 12 %−25 % of the boundary layer thickness. All observed structure heights fall within the log-law region of the flow. Discussed structures include default, diffuser, and nozzle-type geometries, defined by different angles of attack of the three control walls. Instantaneous and time-averaged ensemble data are collected. Manipulations to velocity, Reynolds stresses, and turbulence kinetic energy are discussed. Results show that for 6 mm and 7 mm height surface structures, a default structure geometry produces localized near-wall flow acceleration without significantly perturbing free-stream flow. Further, nozzle geometries produce slight free-stream flow deceleration while diffuser geometries produce slight free-stream flow acceleration. Diffuser geometries produce three downstream regions of noteworthy turbulence energy production. Nozzle geometries produce a large region of intense turbulence energy production over the structure’s top wall. Additionally, certain 6 mm height structure geometries impact turbulence statistics more than 7 mm height structures. Recommendations are made for future study.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"166 ","pages":"Article 111471"},"PeriodicalIF":2.8,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143601049","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}
引用次数: 0
The effect of the chamfered-corner ratio on the characteristics of the wake behind a square and a 2:1 rectangular section model: PIV measurements and POD analysis 倒角比对正方形和2:1矩形模型后尾迹特性的影响:PIV测量和POD分析
IF 2.8 2区 工程技术
Experimental Thermal and Fluid Science Pub Date : 2025-03-09 DOI: 10.1016/j.expthermflusci.2025.111470
Chin-Chen Chou, Kuan-Zu Lee, Cheng-Yang Chung, Kung-Ming Chung
{"title":"The effect of the chamfered-corner ratio on the characteristics of the wake behind a square and a 2:1 rectangular section model: PIV measurements and POD analysis","authors":"Chin-Chen Chou,&nbsp;Kuan-Zu Lee,&nbsp;Cheng-Yang Chung,&nbsp;Kung-Ming Chung","doi":"10.1016/j.expthermflusci.2025.111470","DOIUrl":"10.1016/j.expthermflusci.2025.111470","url":null,"abstract":"<div><div>Corner-chamfering influences flow characteristics around a 2-dimensional prism to mitigate wind load and wind-induced responses; the side ratio is also an important parameter. This study determines the effect of a corner chamfer on the wake from a 2-dimensional prism (<em>B/D</em> = 1) and a rectangular cross-sectional model for which <em>B/D</em> = 2, where <em>B</em> is the width and <em>D</em> is the height. The effect of the chamfer ratio (<em>C/D</em>, where <em>C</em> represents the length of the chamfer corner) on the leading edge of a models is determined in terms of flow characteristics. The wake strength and the structural integrity of the model are also affected by the chamfer corner ratio.</div><div>Velocity and vortex fields are created using Particle Image Velocimetry (PIV) measurements in a wind tunnel for <em>Re</em> = 1.05 × 10<sup>4</sup>. The results show that the mean and the root-mean-square (RMS) velocity coefficients and the turbulent kinetic energy (TKE) in wake region are affected by the value of <em>C/D</em>. The Strouhal number (<em>St</em>) increases as the value of <em>C/D</em> increases for a model for which <em>B/D</em> = 2. The formation length (<em>L<sub>F</sub></em>) increases for a model for which <em>B/D</em> is 1 if corners are chamfered and <em>L<sub>F</sub></em> decreases for a model for which <em>B/D</em> is 2. Chamfered corners can increase vortex shedding frequency for a model for which <em>B/D</em> is 1 and 2.</div><div>The velocity component is the input data for proper orthogonal decomposition (POD). POD mode analysis shows that, for a model for which <em>B/D</em> = 1, the energy of the dominant modes increases with <em>C/D</em> but for a model for which <em>B/D</em> = 2, the energy of the dominant modes decreases as <em>C/D</em> increases. The distribution of temporal coefficients (<span><math><msub><mi>a</mi><mn>1</mn></msub></math></span> and <span><math><msub><mi>a</mi><mn>2</mn></msub></math></span>) for a model for which <em>B/D</em> = 1 that has no chamfered corners resembles a sine wave, which is more stable than the distribution for a model with chamfered corners. As <em>C/D</em> increases, the distribution for <em>a<sub>1</sub></em> and <em>a<sub>2</sub></em> for a model for which <em>B/D</em> = 2 gradually become stable, so vortex shedding is symmetrical.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"166 ","pages":"Article 111470"},"PeriodicalIF":2.8,"publicationDate":"2025-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143642773","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}
引用次数: 0
Characterization of free-surface vortex evolution and its impact on hydraulic stability of the pump sump 自由表面涡演化特征及其对泵水池水力稳定性的影响
IF 2.8 2区 工程技术
Experimental Thermal and Fluid Science Pub Date : 2025-03-05 DOI: 10.1016/j.expthermflusci.2025.111466
Bowen Zhang , Lei Ma , Li Cheng , Baoshan Zhu , Yonglin Qin
{"title":"Characterization of free-surface vortex evolution and its impact on hydraulic stability of the pump sump","authors":"Bowen Zhang ,&nbsp;Lei Ma ,&nbsp;Li Cheng ,&nbsp;Baoshan Zhu ,&nbsp;Yonglin Qin","doi":"10.1016/j.expthermflusci.2025.111466","DOIUrl":"10.1016/j.expthermflusci.2025.111466","url":null,"abstract":"<div><div>Free-surface vortices (FSVs) and their associated air entrainment can induce unstable flow within the sump, thereby impacting hydraulic systems’ efficiency and operational safety. An experiment studied how the submergence depth of a bellmouth affects the spatiotemporal evolution and pressure fluctuation characteristics of an FSV, using high-speed visualization and transient pressure measurements on a transparent hydraulic platform with an axial-flow pump. The results indicate that FSV evolution has four stages: newborn (stage 1), development (stage 2), fully-developed (stage 3) and dissipation (stage 4). Shorter submergence depths lead to quicker evolution periods and distinct FSV morphologies. The scale characteristics of FSV were quantitatively elucidated using the grayscale value extraction method. As the submergence depth increases, the scale of the vortex core gradually expands, and the precursor point for FSV occurrence gradually deviates from the bellmouth. Time-domain characteristics induced by FSV exhibit short-term pressure distortion, with amplitude increasing as the submergence depth decreases, especially at the minimum submergence depth. The frequency spectrum station with FSV is higher than without FSV, and the frequency bandwidth where the blade’s passing frequency is narrower, reducing harmonic energy.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"166 ","pages":"Article 111466"},"PeriodicalIF":2.8,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143577568","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}
引用次数: 0
Experimental investigation of lean blow-out on bluff-body stabilized flames using simultaneous OH/kerosene-PLIF measurements in partially vapourised kerosene 在部分汽化煤油中同时测量OH/煤油- plif对崖体稳定火焰贫爆的实验研究
IF 2.8 2区 工程技术
Experimental Thermal and Fluid Science Pub Date : 2025-03-04 DOI: 10.1016/j.expthermflusci.2025.111458
Guohua Wu , Xin Yu , Jiangbo Peng , Chaobo Yang , Bin Hu , Zhen Cao , Yingjie Song
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