Experimental Thermal and Fluid Science最新文献

{"title":"Development of thin loop heat pipe for compact electronics","authors":"Kelvin Guessi Domiciano,&nbsp;Larissa Krambeck,&nbsp;Marcia Barbosa Henriques Mantelli","doi":"10.1016/j.expthermflusci.2025.111510","DOIUrl":"10.1016/j.expthermflusci.2025.111510","url":null,"abstract":"<div><div>This study experimentally evaluates the thermal performance of a thin diffusion-bonded loop heat pipe (LHP) designed for electronics cooling applications. The device represents the third generation of an LHP with the same top-view dimensions of 76 x 60 mm² and an identical wick structure. However, the thickness has been progressively reduced from 1.6 mm to 1.1 mm, and now to 0.8 mm. Despite this reduction, the LHP demonstrates good thermal performance. An advanced testing workbench, simulating actual electronic operating conditions, enables performance evaluation in horizontal, gravity-assisted, and against-gravity orientations. The evaporator and part of the condenser incorporate a sintered copper powder wick structure. While the lowest thermal resistance of 2.16 °C/W is observed in the gravity-assisted orientation, the LHP operates nearly independent of gravitational effects, exhibiting comparable thermal resistances in all orientations. The reduction in internal channel thickness led to an average decrease of 50 % in thermal performance compared to previous generations with thicker channels (1 mm and 0.5 mm). Nonetheless, the current LHP remains highly suitable for electronic applications due to its thin profile, efficiency, and ability to dissipate up to 8 W/cm² without exceeding the maximum operating temperature of 100 °C.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"168 ","pages":"Article 111510"},"PeriodicalIF":2.8,"publicationDate":"2025-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143913118","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":"Alternative experimental method in investigations of thermal diffusivity of 3D printing material","authors":"Marek Markowicz ,&nbsp;Rafał Gałek ,&nbsp;Paweł Gil ,&nbsp;Joanna Wilk ,&nbsp;Michał Korzeniowski","doi":"10.1016/j.expthermflusci.2025.111512","DOIUrl":"10.1016/j.expthermflusci.2025.111512","url":null,"abstract":"<div><div>The paper presents an alternative technique for determining the thermal diffusivity of the material used for 3D printing – PET-G filament. In the study the thermal regular regime method was applied. The presented method based on simple time and temperature measurements allows for accurate and economical determination of thermal diffusivity of 3D printed elements used in various technical applications. Due to the fact that thermal diffusivity is an important thermophysical parameter in the analysis of transient heat transfer processes, knowledge about it is necessary to determine the quality of various types of engineering materials. Such material is the filament used for 3D printing – polyethylene terephthalate glycol-modified PET-G. A review of the latest literature did not reveal any works on the possibility of applying the presented method to the 3D printed materials. The method applied in the investigations made it possible to testing the material in the form directly obtained in the 3D printing process. Spherical test samples printed with the use of the FFF (fused filament fabrication) technology were used. The shape of samples enabled the use of the solution of transient heat conduction equation in a sphere. Three spherical models with different radius were investigated. In order to meet the condition of Bi → ∞, necessary for the assumed hypotheses of the thermal regular regime method, the approximate measurements of heat transfer coefficient and thermal conductivity of the tested material were performed. The results of thermal diffusivity measurements were compared with the results obtained by the classic laser flash method, which was used to measure the thermal diffusivity of the melted down PET-G fiber. The received results of thermal diffusivity: 0.125∙10⁻⁶ m²/s for the sample printed from PET-G fiber and 0.137∙10⁻⁶ m²/s for the basic material – melted PET-G fiber, indicate the need for the research presented in the work.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"168 ","pages":"Article 111512"},"PeriodicalIF":2.8,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143913119","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 investigation on printed circuit sensor performance for two-phase flow measurement in narrow channels","authors":"Yiang Yang ,&nbsp;Rongxuan Zhang ,&nbsp;Jinbiao Xiong","doi":"10.1016/j.expthermflusci.2025.111507","DOIUrl":"10.1016/j.expthermflusci.2025.111507","url":null,"abstract":"<div><div>Printed circuit sensors (PCS) have demonstrated promising potential to tackle the challenges in two-phase flow measurement in narrow channels. Sensor geometric configuration, bubble shape and data processing algorithm are crucial factors influencing the measurement uncertainty. In order to promote the application of PCS in narrow channels, an experimental setup with flexibility to adjust the channel gap has been established. The sensors with a variety of electrode pitches are used to measure the volume fraction of ceramic slice with precisely known geometry in different gap sizes. The local void fraction characteristics, as well as the uncertainties of two-phase flow parameters, are assessed in detail. Results show that the uncertainty of local void fraction measurement is primarily affected by two dimensionless parameters: <span><math><msup><mrow><mi>L</mi></mrow><mrow><mo>∗</mo></mrow></msup></math></span>, which is the dimensionless distance to the bubble edge, and <span><math><msubsup><mi>l</mi><mrow><mi>e</mi></mrow><mrow><mo>∗</mo></mrow></msubsup></math></span>, the dimensionless sensor electrode pitch. It is recommended to configure the sensor with <span><math><mrow><msubsup><mi>l</mi><mrow><mi>e</mi></mrow><mrow><mo>∗</mo></mrow></msubsup><mo>=</mo><mn>0.6</mn></mrow></math></span> to allow for clear distinction between the gas and liquid phases at high spatial resolution. The Maxwell correlation, combined with the noise elimination method, is recommended to derive high-accuracy average void fraction. The relative error of measured average void fraction can be within ± 10 % for most of the cases, provided that the dimensionless bubble thickness <span><math><msup><mrow><mi>h</mi></mrow><mrow><mo>∗</mo></mrow></msup></math></span> is greater than 0.8. The accuracy of the projected area equivalent bubble diameter and perimeter depends on the ratio of bubble diameter to sensor electrode pitch <span><math><msup><mrow><mi>d</mi></mrow><mrow><mo>∗</mo></mrow></msup></math></span>. The relative error of bubble diameter and perimeter derived from the resolution-enhanced data is mostly within ± 20 % for 1 &lt; <span><math><mrow><msup><mrow><mi>d</mi></mrow><mrow><mo>∗</mo></mrow></msup><mo>≤</mo><mn>10</mn></mrow></math></span>and within ± 10 % for <span><math><mrow><msup><mrow><mi>d</mi></mrow><mrow><mo>∗</mo></mrow></msup><mo>&gt;</mo><mn>10</mn></mrow></math></span>.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"168 ","pages":"Article 111507"},"PeriodicalIF":2.8,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143899019","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":"Aerodynamic flame stabilization at sub-limit global equivalence ratio, exploiting high velocity ratio coaxial jets: An experimental approach","authors":"Stavros-Marios Panou,&nbsp;Michalis Manoudakis,&nbsp;Evangelos-Panagiotis Mitsopoulos,&nbsp;Konstantinos Souflas,&nbsp;Panayiotis Koutmos","doi":"10.1016/j.expthermflusci.2025.111504","DOIUrl":"10.1016/j.expthermflusci.2025.111504","url":null,"abstract":"<div><div>This work investigates the flow and flame stabilization characteristics of a novel partially premixed aerodynamic flame stabilization configuration. Flames are established in the interaction region of high velocity ratio coaxial jets, at the location where the local flame speed and the reacting flow velocity match. The isothermal flow and mixing field characteristics are first experimentally investigated at four velocity ratios, ranging from 5 to 9, to delineate the operating conditions that promote the formation of a centrally located recirculation region. Combined with a suitable and freely adjustable fuel injection methodology, that supplies the reacting region with a locally flammable mixture, an inverted bowl-shaped flame is aerodynamically established, at sub-limit global equivalence ratio values, with ignition. These flames have no fixed edge anchoring point and remain relatively stationary throughout the investigated load variations, suffering no heat losses to the burner. Particle Image Velocimetry, Fourier Transform Infrared Spectroscopy, Mie scattering and OH* Chemiluminescence measurements have been conducted to investigate the flow and mixing characteristics, flame topology and turbulence effects as well as displacement speed correlations with turbulence intensity. Results indicated that the flame brush location and topology are demarcated by the flame induced accelerating region and maximum OH* chemiluminescence intensity with local Damköhler (<span><math><mrow><mi>Da</mi></mrow></math></span>) and Karlovitz (<span><math><mrow><mi>Ka</mi></mrow></math></span>) numbers suggesting that flame stability is primarily governed by reaction kinetics rather than turbulence effects. Finally, the local displacement speeds revealed a lineal correlation with the fluctuating velocities, for the flame configurations studied, highlighting characteristic resemblances with the typical low-swirl burner setup.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"168 ","pages":"Article 111504"},"PeriodicalIF":2.8,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143899020","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 study for enhancing accuracy of POD analysis for near wake behind circular cylinder","authors":"Keh-Chin Chang,&nbsp;Tzu-Hsun Lin,&nbsp;Chia-Chun Chu","doi":"10.1016/j.expthermflusci.2025.111506","DOIUrl":"10.1016/j.expthermflusci.2025.111506","url":null,"abstract":"<div><div>This study performs a parametrical study of the proper orthogonal decomposition (POD) for the near wake behind a circular cylinder. Two cases with Reynolds numbers (Re, based on the cylinder diameter) of 3840 and 9440 are tested. The study confirms that the field of view (FOV) must not be less than the maximum spacing (<span><math><mrow><mi>λ</mi></mrow></math></span>) between the vortices in the K<span><math><mrow><mover><mi>a</mi><mo>́</mo></mover></mrow></math></span>rm<span><math><mrow><mover><mi>a</mi><mo>́</mo></mover></mrow></math></span>n vortex street and the FOV should be as close to <span><math><mrow><mi>λ</mi></mrow></math></span> as possible to provide better image solution in the measurement using the particle image velocimetry (PIV) for the POD analysis. The accuracy of the PIV measurement determines the minimum number of image pairs (MT) that is required to achieve statistically stationary results for the POD analysis. It shows that 14000 &lt; MT &lt; 260000 at different upstream subregions for the two tested cases. A criterion based on the accuracy of the PIV measurement is proposed to determine the number of leading modes (m) for the low dimensional representation of fluid dynamics. The study shows that the values of MT and m increase as Re increases and m <span><math><mrow><mo>≪</mo><mi>M</mi><mi>T</mi></mrow></math></span>. Moreover, the MT value increases as the subregion of interest moves to more downstream of wake flow due to decay of the K<span><math><mrow><mover><mi>a</mi><mo>́</mo></mover></mrow></math></span>rm<span><math><mrow><mover><mi>a</mi><mo>́</mo></mover></mrow></math></span>n vortex street.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"168 ","pages":"Article 111506"},"PeriodicalIF":2.8,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143886421","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":"Measurements of the vortex structure in the wake of a scale helicopter rotor in forward motion","authors":"Bradley Gibeau,&nbsp;Ed Soltys,&nbsp;Sina Ghaemi","doi":"10.1016/j.expthermflusci.2025.111503","DOIUrl":"10.1016/j.expthermflusci.2025.111503","url":null,"abstract":"<div><div>This paper provides experimental insight into the vortex structures that form in the wake of a scale helicopter rotor in forward motion. Time-resolved stereoscopic particle image velocimetry was used to capture the vortices that form on the advancing and retreating sides of the rotor at an advance ratio of 0.20. The rotor radius was <em>R</em> = 425 mm and its two blades with chord length <em>c</em> = 35 mm spun at 1,500 RPM, resulting in a Reynolds number of <em>U</em>_tip<em>R</em>/<em>ν</em> = 1.7 × 10⁶ (<em>U</em>_tip<em>c</em>/<em>ν</em> = 1.4 × 10⁵) where <em>U</em>_tip is the blade tip speed. The collective, lateral cyclic, and longitudinal cyclic pitch settings were varied one at a time. The structure of vortices measured in the wake was compared to reference paths that we expect the vortices to take if they advect into the wake at a constant velocity without interaction. We find that the vortices on the retreating side of the rotor closely match the reference paths. Conversely, the vortices on the advancing side often exhibited large deviations from the paths. The vortices on both sides of the rotor had opposite directions of rotation when the collective pitch setting was varied. In contrast, varying the lateral and longitudinal cyclic pitch resulted in the formation of vortices with the same direction of rotation on the advancing and retreating sides. Notable vortex formation was observed on both sides of the rotor when the lateral cyclic pitch setting was varied, while vortex formation was dominant on the advancing side when varying the longitudinal cyclic pitch.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"168 ","pages":"Article 111503"},"PeriodicalIF":2.8,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143881823","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 and interactions of counter-rotating waves in rotating detonation combustors","authors":"Provence Barnouin ,&nbsp;Christian Oliver Paschereit ,&nbsp;Eric Bach ,&nbsp;Myles D. Bohon","doi":"10.1016/j.expthermflusci.2025.111486","DOIUrl":"10.1016/j.expthermflusci.2025.111486","url":null,"abstract":"<div><div>Better understanding of non-canonical modes such as counter-rotating wave dynamics provides valuable insights for future rotating detonation engine injector design and combustion mode control. The objective of this work is to study the dynamics and interactions of counter-rotating waves in an RDC experimentally. Previous experimental and numerical data suggest that at collision points, the resulting pressure amplitude is not necessarily the result of a linear combination between the waves, but rather a more complex interaction. In this study, we analyze temporally resolved, high-speed pressure and luminosity data for two counter-rotating waves propagating at equal (2CR) and different (2CRT) speeds. This analysis employs a soft-dynamic time warping averaging scheme, which preserves the shape of the data even in the presence of lap-to-lap fluctuations. From this analysis, the non-linear pressure and luminosity interaction at collision is quantified over the wave lap and for different geometries and operating conditions. Notably, it is found that the strength of the non-linearity at collision is mode dependent and increases as one wave becomes stronger relative to the other one. Furthermore, a one-dimensional gas dynamics model is applied to capture wave collisions in an RDC. The model captures the counter-rotating wave interaction in the 2CR mode, indicating that these waves behave like shock waves. However, in the 2CRT mode, the model underestimates the collision pressure, suggesting that additional mechanisms contribute to the nonlinear interaction between the counter-rotating waves.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"168 ","pages":"Article 111486"},"PeriodicalIF":2.8,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143890986","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":"Characterization of splashing and regime thresholds for oblique droplet impact on thin wall films","authors":"Jonathan Lukas Stober ,&nbsp;Maurizio Santini ,&nbsp;Kathrin Schulte","doi":"10.1016/j.expthermflusci.2025.111493","DOIUrl":"10.1016/j.expthermflusci.2025.111493","url":null,"abstract":"<div><div>This study experimentally investigates oblique droplet impacts on thin wall films, providing new insights into crown formation, splashing types, and threshold modelling. Different splashing types were identified by varying the impact angle <span><math><mi>α</mi></math></span> and Weber number <span><math><mrow><mi>W</mi><mi>e</mi></mrow></math></span>, keeping the film thickness <span><math><mrow><mi>δ</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>22</mn></mrow></math></span> and fluid (isopropanol) constant. The splashing types include secondary droplet ejection only from the front or only from the sides of the crown, splashing caused by crown-film interaction, and 90°-like splashing. Combinations of these mechanisms, such as simultaneous front and side splashing, were also observed, as their triggering mechanisms are independent and allow for a superposition of regimes. A regime map and threshold formulations were developed to describe the distinct splashing types. The front splashing limit lies at <span><math><mrow><mo>cos</mo><mrow><mo>(</mo><mi>α</mi><mo>)</mo></mrow><mspace></mspace><mi>W</mi><mi>e</mi><mo>=</mo><mn>128</mn></mrow></math></span>, which reveals that the <span><math><mrow><mo>cos</mo><mrow><mo>(</mo><mi>α</mi><mo>)</mo></mrow></mrow></math></span> is the relevant physical quantity beside the Weber number. Side splashing depends solely on the wall-normal Weber number (<span><math><mrow><mi>W</mi><msub><mrow><mi>e</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>=</mo><mn>425</mn></mrow></math></span>). Crown-film interactions occur below <span><math><mrow><mi>α</mi><mo>&lt;</mo><mn>60</mn><mo>°</mo></mrow></math></span> if the Weber number is high enough, while splashing similar to that seen when <span><math><mrow><mi>α</mi><mo>=</mo><mn>90</mn><mo>°</mo></mrow></math></span> is observed if the impact angle exceeds <span><math><mrow><mi>α</mi><mo>&gt;</mo><mn>81</mn><mo>°</mo></mrow></math></span>.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"167 ","pages":"Article 111493"},"PeriodicalIF":2.8,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143855075","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":"Flow field analysis of submerged oblique and normally impinging twin jets at varying impinging angles","authors":"C. Sandoval ,&nbsp;C. Treviño ,&nbsp;A. Alvarez ,&nbsp;D. Matuz ,&nbsp;J. Lizardi ,&nbsp;L. Martínez-Suástegui","doi":"10.1016/j.expthermflusci.2025.111491","DOIUrl":"10.1016/j.expthermflusci.2025.111491","url":null,"abstract":"<div><div>In this work, two-dimensional time-resolved particle image velocimetry (TR-PIV) measurements are carried out to study the flow structure and impinging interactions of two turbulent submerged isothermal circular impinging water jets. In this configuration, the uphill and downhill jets impinge obliquely and normally onto a flat target surface, respectively. A comprehensive parametric study is carried out for values of the jets’ exit Reynolds number of <span><math><mrow><mi>R</mi><msub><mrow><mi>e</mi></mrow><mrow><mi>j</mi></mrow></msub><mo>=</mo><mn>5000</mn></mrow></math></span> and 8000, jets’-to-surface target distances of <span><math><mrow><mi>H</mi><mo>/</mo><mi>D</mi><mo>=</mo><mn>3</mn></mrow></math></span> and 5, and inclination angles of the uphill oblique jet-to-impingement surface of (<span><math><mrow><msub><mrow><mi>θ</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>=</mo></mrow></math></span>30°, 45°, 60°). For all the experiments, the jet-to-jet spacing distances were varied for each impingement angle of the oblique jet so that the impingement point of both jets coincide at the geometric intersection of the jets’ axes. Flow visualization images showing ensemble-averaged and instantaneous flow distributions and turbulent characteristics for equal and non-equal Reynolds numbers of the jets are presented. Velocity profiles and Reynolds shear stress distributions of the downhill wall jet development and its corresponding dimensionless shedding frequencies are also obtained. A proper orthogonal decomposition (POD) analysis reveals the spatial structure of the dominant fluctuation motions of the turbulent flow as well as their respective contributions to the total kinetic energy. Our results show that the jets’ exit Reynolds numbers, the oblique impingement angle of the uphill jet and the jets’-to-surface distance play a major role on the complex flow structure and dynamics, location of the stagnation point and entrainment characteristics of the turbulent flow field of the twin jets.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"167 ","pages":"Article 111491"},"PeriodicalIF":2.8,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143833432","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":"Measurement of particulates formed during thermal protection system spallation in an arc-jet environment","authors":"K.J. Price,&nbsp;A. Martin,&nbsp;S.C.C. Bailey","doi":"10.1016/j.expthermflusci.2025.111487","DOIUrl":"10.1016/j.expthermflusci.2025.111487","url":null,"abstract":"<div><div>An arc-jet campaign conducted in the Aerodynamic Heating Facility at NASA Ames was conducted to investigate the spallation of thermal protection system materials by estimating the size of particles ejected from these materials, as well as the corresponding mass loss. Particle sizes were determined both from analysis of particle tracking velocimetry, utilizing a force balance on the particulates, and by direct measurement of particles captured through targeted design of the test articles. Analysis of the captured particles revealed that they took on different geometries consisting of fine particulates, individual fibers, and clumps of multiple fibers. Different methods were required for each particle sizing approach to determine particle quantities, and corresponding mass loss. However, similar values for mass loss were determined using both techniques. In addition, it was found that the particle size distributions were independent of surface heat flux, and whether the carbon preform contained additional phenolic resin. It was found, however, that the presence of phenolic resin caused a measurable reduction in the rate of particle production, potentially due to its pyrolysis reducing the diffusion of oxygen from the free stream into the sample.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"167 ","pages":"Article 111487"},"PeriodicalIF":2.8,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143821567","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}