International Journal of Heat and Fluid Flow最新文献

{"title":"Impact of blade twisting and tip clearance on centrifugal pump performance under air–water two-phase flow","authors":"Michael Mansour ,&nbsp;Dominique Thévenin","doi":"10.1016/j.ijheatfluidflow.2024.109682","DOIUrl":"10.1016/j.ijheatfluidflow.2024.109682","url":null,"abstract":"<div><div>The performance characteristics of a centrifugal pump were investigated experimentally for different conditions of air–water two-phase flow. A 3D semi-open impeller (with twisted blades) and a geometrically similar 2D semi-open impeller (with straight elliptical blades) were employed to compare the pump behavior using each of them, revealing the influence of the blade twisting. Additionally, the effect of the tip clearance gap on the performance of each impeller was investigated by employing either a standard or an increased gap. A rotational speed of 1450 rpm was set for all experiments. The performance of the pump was reported and described for either a constant gas volume fraction or a constant air flow rate at the pump inlet. Possible hysteresis effects were studied by approaching the desired operating conditions using different procedures. The head degradation behavior, the pump surging conditions, and the flow instabilities were considered as well. The two-phase flow regimes were recorded and identified for all the considered cases using a high-speed recording system. The results show that for single-phase flow, both impellers perform similarly, with the 3D impeller showing slight advantages at part-load and the 2D impeller excelling at near-optimal and overload conditions. For two-phase flows with high gas volume fractions, the 3D impeller maintains better performance at overload, while the 2D impeller performs better at part-load conditions. Increasing the gap slightly improves performance for gas volume fractions between 5% and 7% in both impellers. Additionally, the 2D impeller demonstrates a stronger ability to suppress and delay surging and flow instabilities compared to the 3D impeller, making it preferable for applications requiring stable operation across a range of gas volume fractions and load conditions.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"112 ","pages":"Article 109682"},"PeriodicalIF":2.6,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143140143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transition model based on the laminar kinetic energy concept for the prediction of all transition modes","authors":"M. Dellacasagrande ,&nbsp;A. Ghidoni ,&nbsp;G. Noventa ,&nbsp;D. Simoni","doi":"10.1016/j.ijheatfluidflow.2024.109680","DOIUrl":"10.1016/j.ijheatfluidflow.2024.109680","url":null,"abstract":"<div><div>Separation-induced transition showed to be the weakness of the transition models based on the laminar kinetic energy concept. In fact, these models contemplate only the Tolmien–Schlichting waves, for the natural mode, and the Klebanoff streaks, for the bypass mode. Literature is very poor about the use of these models to cases with the separation-induced mode and in all these works no proofs of the phenomenological agreement between the models and the physics of the flow are spotlighted. A further improvement for the Reynolds-Averaged Navier–Stokes equations in separated and transitional shear layers needs more accurate models to describe the physics behind the phenomena, e.g., the introduction of ad-hoc designed terms for the Kelvin–Helmholtz instability in the transport equations. The objective of this work is to assess a phenomenological and local transition model based on the laminar kinetic energy concept, implemented in a high-order discontinuous Galerkin solver, for the simulation of transitional flows. The prediction capabilities of the model are proved with the simulations of the flow over the ERCOFTAC and UNIGE flat plates, characterized by the bypass and separation-induced mode of transition. The education of the model is not only based on integral coefficients and first-order statistics, but also on the turbulence intensity, laminar and turbulent kinetic energy distributions extracted from finely processed experimental data.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"112 ","pages":"Article 109680"},"PeriodicalIF":2.6,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143140447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of the heat transfer performance of two-phase flow in a novel step-by-step distributed heat exchanger","authors":"Shuang-gen Yang ,&nbsp;Huan-ling Liu","doi":"10.1016/j.ijheatfluidflow.2024.109687","DOIUrl":"10.1016/j.ijheatfluidflow.2024.109687","url":null,"abstract":"<div><div>With the miniaturization of electronic chips, and the complexity and diversity of functions, the application of multiple heat source arrays has appeared in recent years. In order to improve the heat dissipation performance of multiple high heat flux chips, this work innovatively designs a step-by-step distributed heat exchanger (SSD), which uses ethanol as coolant and is used for two-phase flow heat dissipation. Then, in order to improve the cooling ability, a crossed step-by-step distributed heat exchanger (CSSD) is proposed by arranging cross flow channels with high heat flux. The VOF two-phase flow numerical method is used to simulate the performance of these two kinds of heat exchangers. In addition, the effects of gravity and inlet height on the performance of the heat CSSD exchanger are studied. The results show that CSSD can shorten the bubble generation time, increases the gas volume fraction in the channel, increase the gas disturbance, and intensify the heat dissipation of two-phase flow compared to the SSD design. The results show that CSSD can reduce the maximum temperature of the heat exchanger and improve the temperature uniformity. Gravity has little effect on two-phase flow heat transfer. In addition, we set up a two-phase flow experimental system to verify the correctness of the numerical simulation. The results indicates that the numerical results are consistent with the experimental results.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"112 ","pages":"Article 109687"},"PeriodicalIF":2.6,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143140133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Additive-feature-attribution methods: A review on explainable artificial intelligence for fluid dynamics and heat transfer","authors":"Andrés Cremades ,&nbsp;Sergio Hoyas ,&nbsp;Ricardo Vinuesa","doi":"10.1016/j.ijheatfluidflow.2024.109662","DOIUrl":"10.1016/j.ijheatfluidflow.2024.109662","url":null,"abstract":"<div><div>The use of data-driven methods in fluid mechanics has surged dramatically in recent years due to their capacity to adapt to the complex and multi-scale nature of turbulent flows, as well as to detect patterns in large-scale simulations or experimental tests. In order to interpret the relationships generated in the models during the training process, numerical attributions need to be assigned to the input features. One important example are the additive-feature-attribution methods. These explainability methods link the input features with the model prediction, providing an interpretation based on a linear formulation of the models. The Shapley additive explanations (SHAP values) are formulated as the only possible interpretation that offers a unique solution for understanding the model. In this manuscript, the additive-feature-attribution methods are presented, showing four common implementations in the literature: kernel SHAP, tree SHAP, gradient SHAP, and deep SHAP. Then, the main applications of the additive-feature-attribution methods are introduced, dividing them into three main groups: turbulence modeling, fluid-mechanics fundamentals, and applied problems in fluid dynamics and heat transfer. This review shows that explainability techniques, and in particular additive-feature-attribution methods, are crucial for implementing interpretable and physics-compliant deep-learning models in the fluid-mechanics field.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"112 ","pages":"Article 109662"},"PeriodicalIF":2.6,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143140624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of cooling hole blockage on heat transfer and film cooling effectiveness of gas turbine squealer tip","authors":"Kewen Xu ,&nbsp;Kun He ,&nbsp;Xin Yan","doi":"10.1016/j.ijheatfluidflow.2024.109678","DOIUrl":"10.1016/j.ijheatfluidflow.2024.109678","url":null,"abstract":"<div><div>The complex flow fields in the squealer tip region are conducive to the particle deposition and cooling hole blockage of gas turbine blades. The blockage of film cooling hole causes the elevation of heat load and reduction of film cooling effect in the squealer tip gap. In this paper, influences of cooling hole blockage on the film cooling effectiveness and heat transfer on the squealer tip are investigated by means of numerical methods. To describe the degree of hole blockage, the blockage ratio <em>B</em> and the blockage angle <em>β</em> are introduced for the film cooled squealer tip with cooling hole blockage. The film cooling effectiveness and heat transfer coefficient on the squealer tip are obtained at the three blowing ratios (<em>M</em> = 0.5, 1.0, and 2.0), three blockage ratios (<em>B</em> = 0.2, 0.4, and 0.8), and three blockage angles (<em>β</em> = 20°, 30°, and 40°). The results show that the film cooling effectiveness and heat transfer on the squealer tip is highly dependent on the blockage ratio, but not sensitive to the variation of blockage angle. The cooling hole blockage has a profound effect on the coolant ejection velocity and angle. At <em>M</em> = 0.5 and 1.0, the film cooling effectiveness is reduced by 32.11 % and 39.40 % respectively for the blocked case with <em>B</em> = 0.6 and <em>β</em> = 40° compared to the design case (i.e. no blockage), whereas the averaged heat transfer coefficient on the cavity floor for the blocked case with <em>B</em> = 0.6 and <em>β</em> = 20° is increased by 9.77 % and 12.57 % respectively compared to the design case. The effect of cooling hole blockage on the heat transfer coefficient of the squealer tip exhibits irregular characteristic at <em>M</em> = 2.0. The highest heat load is observed on the squealer tip at <em>B</em> = 0.4 and <em>β</em> = 40°, and the lowest film cooling effectiveness is observed at <em>B</em> = 0.4, <em>β</em> = 30°. In these cases, the averaged film cooling effectiveness is decreased by 25.49 % compared to the design cases, and the averaged heat transfer coefficient on the cavity floor is increased by 14.6 %.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"112 ","pages":"Article 109678"},"PeriodicalIF":2.6,"publicationDate":"2024-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143140141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 mechanism across 180° sharp bend of matrix-cooled serpentine channel","authors":"Nishab Ali,&nbsp;Arun Chand,&nbsp;Vaibhav Sharma,&nbsp;Andallib Tariq","doi":"10.1016/j.ijheatfluidflow.2024.109683","DOIUrl":"10.1016/j.ijheatfluidflow.2024.109683","url":null,"abstract":"<div><div>Vortex merging and evolution mechanisms have been characterized across the 180° sharp bend region of matrix-cooled serpentine channel with the help of stereo Particle Image Velocimetry (<em>PIV</em>) system. Complete evolution of flow phenomenon is captured through measurements in multiple vertical and horizontal planes, and the mechanism responsible for evolution of vortices at a typical Reynolds number (<em>Re</em>) of 6500 has been explored. It was observed that the matrix subchannel typically produces a kind of swirling pattern downstream of the matrix structure, which is similar to the swirling flow occurring in various other application areas. Two co-rotating vortices emanate out of matrix subchannels (observed in secondary plane), which immediately merge into a single vortex at the onset of the bend and propagate further downstream of the bend section, where a pair of side-by-side counter-rotating vortices are observed later. Numerical simulations have also been performed to get the pressure distribution and flow characteristics within oblique/inclined planes along the bend, which are difficult to obtain experimentally through <em>PIV</em>. Results demonstrate that the vortical structures lose their strength during merging and turning, significantly reducing turbulence while passing through the bend. Based on the combination of experimental and numerical observations, a conceptual diagram depicting flow dynamics has been proposed, which provides the overall perspective of vortices evolution and merging across the bend.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"112 ","pages":"Article 109683"},"PeriodicalIF":2.6,"publicationDate":"2024-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143140136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Higher-order turbulent statistics of submerged wall jet over hemispherical macro-rough boundary: Insights from third-order moments, turbulent kinetic energy and length scales","authors":"Sammelan Chowdhury","doi":"10.1016/j.ijheatfluidflow.2024.109676","DOIUrl":"10.1016/j.ijheatfluidflow.2024.109676","url":null,"abstract":"<div><div>This study investigates, for the first time, turbulence in a submerged wall jet over a macro-rough boundary, emphasizing third-order moments, turbulent kinetic energy (TKE) field and budget, and the evolution of turbulent length scales using the instantaneous velocity data captured by Acoustic Doppler Velocimeter or <em>Vectrino</em>. Negative third-order moments in the jet outer layer and inner circulatory flow layer indicate downward and upstream fluxes of Reynolds normal stresses with deceleration. In the jet inner and reverse flow layers, positive values represent upward and downstream fluxes with substantial acceleration, reflecting inward and outward interaction events. Time-averaged TKE field indicates significant fluctuations in all three velocity components near the macro-rough boundary and along the null streamwise velocity line. Near-bed TKE production is higher, decreasing to the edge of jet inner layer, then peaks at maximum Reynolds shear stress. TKE dissipation steeply increases from the boundary, decreasing after the null-point of Reynolds shear stress. Variation of Taylor microscale and Kolmogorov length scale reveals that the Kolmogorov length scale follows similar trends but with smaller magnitudes, ranging from 0.0075 to 0.05 times the Taylor microscale.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"112 ","pages":"Article 109676"},"PeriodicalIF":2.6,"publicationDate":"2024-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143140129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coaxial round water jet at velocity ratios close to unity, Part I: Mean and turbulent flow characteristics","authors":"D. Hasin ,&nbsp;A. Mitra ,&nbsp;R. van Hout","doi":"10.1016/j.ijheatfluidflow.2024.109650","DOIUrl":"10.1016/j.ijheatfluidflow.2024.109650","url":null,"abstract":"<div><div>In this paper, planar time-resolved particle image velocimetry measurements are reported in the near-field of a coaxial jet at velocity ratios, <span><math><msub><mrow><mi>r</mi></mrow><mrow><mi>u</mi></mrow></msub></math></span> = 0.66, 1.0 and 1.32. At each <span><math><msub><mrow><mi>r</mi></mrow><mrow><mi>u</mi></mrow></msub></math></span>, at least two different Reynolds numbers, Re, were investigated. Spatial distributions of mean velocities, Reynolds stresses, vorticity and swirling strength strongly depend on <span><math><msub><mrow><mi>r</mi></mrow><mrow><mi>u</mi></mrow></msub></math></span>. Re effects in the normalized, mean velocity distributions were mainly visible in the wake associated with the finite lip thickness. In addition, increased normalized Reynolds stresses were obtained at <span><math><mrow><mi>x</mi><mo>/</mo><msub><mrow><mi>D</mi></mrow><mrow><mi>o</mi></mrow></msub><mo>≈</mo></mrow></math></span> 1.5 for the lowest Re at a given <span><math><msub><mrow><mi>r</mi></mrow><mrow><mi>u</mi></mrow></msub></math></span>. Farther downstream, Re effects became negligible as inner and outer jets merged. A comparison between different terms in the turbulent kinetic energy (TKE) budget showed that TKE is predominantly produced in the outer shear layer, while turbulent diffusion results in radial transport. Mean advection of TKE (a “sink” term) is mainly significant close to the nozzle exit.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"112 ","pages":"Article 109650"},"PeriodicalIF":2.6,"publicationDate":"2024-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143140134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analytical modeling of simultaneous phase transitions in a low-temperature evaporator for a pilot-scale Organic Rankine Cycle using R134a: A comparative study with water coolant","authors":"Sandeep Aryal,&nbsp;Kwangkook Jeong","doi":"10.1016/j.ijheatfluidflow.2024.109685","DOIUrl":"10.1016/j.ijheatfluidflow.2024.109685","url":null,"abstract":"<div><div>This study focuses on comparing the heat and water recovery performance of two coolants, R134a refrigerant and water, in a low-temperature evaporator (LT-E) designed for a pilot-scale Organic Rankine Cycle (ORC). The primary objectives were to develop a one-dimensional analytical model capable of predicting simultaneous phase transitions—internal flow boiling of R134a and condensation of water vapor from flue gas on the outer tube wall—and to compare the heat and mass transfer performance of R134a with that of water. Baseline modeling conditions included a flue gas temperature of 57.3 °C, coolant inlet temperature of 16 °C, and a coolant mass velocity of 126.4 kg/sm², with inlet pressures of 630 kPa for R134a and 100 kPa for water. The model’s predictions showed average discrepancies of 10 % for water recovery efficiency and 3 % for flue gas exit temperature when compared to experimental data. Case studies revealed that R134a outperformed water in heat flux by 16 % to 67 %, and water recovery efficiency was 15 % to 68 % higher with R134a. Increased heat exchanger surface area improved recovery efficiency for both coolants, eventually reaching an asymptotic limit.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"112 ","pages":"Article 109685"},"PeriodicalIF":2.6,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143140135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Switching between supercritical and subcritical turbulent transitions in inner cylinder rotating Taylor–Couette–Poiseuille flow","authors":"Yuki Matsukawa,&nbsp;Takahiro Tsukahara","doi":"10.1016/j.ijheatfluidflow.2024.109667","DOIUrl":"10.1016/j.ijheatfluidflow.2024.109667","url":null,"abstract":"<div><div>The Taylor–Couette flow between a stationary outer cylinder and rotating inner cylinder undergoes a supercritical transition. After becoming linearly unstable, the flow becomes progressively more complex: as the inner cylinder rotation Reynolds number <span><math><msub><mrow><mi>Re</mi></mrow><mrow><mi>in</mi></mrow></msub></math></span> increases, the flow state changes to the Taylor vortex flow (TVF) <span><math><mo>→</mo></math></span> wavy Taylor vortex flow (WVF) <span><math><mo>→</mo></math></span> modulated wavy Taylor vortex flow (MWV). In contrast, annular Poiseuille flow, driven by an axial pressure gradient in concentric cylinders, undergoes a subcritical transition. Its subcritical turbulent flow features helical-shaped localized turbulence (HLT). The Taylor–Couette–Poiseuille flow, which is a combined shear flow of cylinder-rotation-driven flow and axial pressure-driven flow, is the subject of this study. We investigated the flow state transition processes for a high radius ratio of 0.883 at three different <span><math><msub><mrow><mi>Re</mi></mrow><mrow><mi>in</mi></mrow></msub></math></span> values, using direct numerical simulations. We demonstrated that in the TVF and WVF-based cases, the pressure-driven axial flow stabilized into the Taylor-vortex-free flow field, with the WVF state transitioning to the TVF state before laminarization. A further increase in the axial pressure gradient led to intermittent turbulence, similar to HLT. These facts indicate that the switch from supercritical to subcritical transitions occurs across laminarization. In the MWV-based case, at a higher <span><math><msub><mrow><mi>Re</mi></mrow><mrow><mi>in</mi></mrow></msub></math></span>, the flow does not exhibit laminarization but becomes fully turbulent, unlike in the lower <span><math><msub><mrow><mi>Re</mi></mrow><mrow><mi>in</mi></mrow></msub></math></span> cases. However, the waviness of the Taylor vortex disappeared, and the pre-multiplied energy spectra confirmed partial stabilization before the transition to turbulence. From the perspective of Lumley’s anisotropic invariant map, the TVF- and WVF-based cases have one- or two-component anisotropy under all conditions. However, the MWV-based case becomes continuously similar to the anisotropic map of typical turbulent channel flow as <span><math><mrow><mi>F</mi><mrow><mo>(</mo><mi>P</mi><mo>)</mo></mrow></mrow></math></span> increases.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"112 ","pages":"Article 109667"},"PeriodicalIF":2.6,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143140175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}