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Simultaneous Analysis of Swirl Spray Dynamics Using a Telecentric System

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SSRN 2023年

作者： Machado, Danilo Almeida de Souza Costa, Fernando Dias, Gabriel Silva Mota, Fábio A.S. Combustion and Propulsion Laboratory National Institute for Space Research SP Cachoeira Paulista12630-000 Brazil State Key Laboratory of Multiphase Flows in Power Engineering Xi’an Jiaotong University Shanxi Xi’an710049 China

A telecentric shadowgraphy optical system was utilized to determine macroscopic and microscopic parameters of sprays and the measurement of conical liquid films formed by dual pressure swirl injectors. Spray cone angles, breakup lengths, mean droplet velocities, momentum flows, wave amplitude ratios and maximum wave growth rates were simultaneously measured using high-speed images with kHz frequencies. Two injectors were tested with inner nozzles having Abramovich geometric constants Kint = 2 and 2.125 and external nozzles with geometric constants Kext = 2.9 and 1.9792, respectively. Injection pressures were varied from 0.05 to 0.5 MPa and water was used as test fluid. The experimental data indicate that the breakup length, droplet velocity, flow momentum and disturbance amplitude ratio are higher for injectors with larger mass flow rates, for a given injection pressure. The maximum amplitude ratios of the conical liquid film disturbances varied in the range 2.32 © 2023, The Authors. All rights reserved.

关键词： Liquid films

Simultaneous Analysis of Liquid Film Instabilities and Properties of Swirl Sprays by Telecentric Shadowgraphy

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SSRN 2023年

作者： Machado, Danilo Almeida Costa, Fernando S. Dias, Gabriel Silva Mota, Fábio A.S. Combustion and Propulsion Laboratory National Space Research Institute SP Cachoeira Paulista12630-000 Brazil State Key Laboratory of Multiphase Flows in Power Engineering Xi’an Jiaotong University Shanxi Xi’an710049 China

A telecentric shadowgraphy optical system was utilized to determine macroscopic and microscopic parameters of sprays and the measurement of conical liquid films formed by dual pressure swirl injectors. Spray cone angles, breakup lengths, mean droplet velocities, momentum flows, wave amplitude ratios and maximum wave growth rates were simultaneously measured using high-speed images with kHz frequencies. Two injectors were tested with inner nozzles having Abramovich geometric constants Kint = 2 and 2.125 and external nozzles with geometric constants Kext = 2.9 and 1.9792, respectively. Injection pressures were varied from 0.05 to 0.5 MPa and water was used as test fluid. The experimental data indicate that the breakup length, droplet velocity, flow momentum and disturbance amplitude ratio are higher for injectors with larger mass flow rates, for a given injection pressure. On the other hand, the maximum wave growth rate of the liquid film is higher for injectors with smaller mass flow rates. The maximum amplitude ratios of the conical liquid film disturbances varied in the range 2.32 © 2023, The Authors. All rights reserved.

关键词： Liquid films

Accelerated methane storage in clathrate hydrates using surfactantstabilized suspension with graphite nanoparticles

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Chinese Journal of Chemical engineering 2020年第4期28卷 1112-1119页

作者： Liang Yang Xin Wang Daoping Liu Guomin Cui Binlin Dou Juan Wang Shuqing Hao Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering School of Energy and Power EngineeringUniversity of Shanghai for Science and TechnologyShanghai 200093China School of Environmental and Chemical Engineering Shanghai University of Electric PowerShanghai 200090China National Engineering Research Center of Coal Preparation and Purification China University of Mining&TechnologyXuzhou 221116China

In this study,enhanced kinetics of methane hydrate formation in the sodium dodecyl sulfate(SDS)solution with different concentrations of suspended graphite nanoparticles(GNPs)were investigated at 6.1-9.0 MPa and 274.15 *** GNPs with rough surfaces and excellent thermal conductivity not only provided a considerable number of microsites for hydrate nucleation but also facilitated the fast hydrate heat transfer in the suspension *** a relatively low pressure of 6.1 MPa,the suspension with 0.4 wt%of GNPs exhibited the minimum induction time of 22 min and maximum methane uptake of 126.1 cm3·***,the methane storage performances of the suspensions with higher and lower concentrations of GNPs were not *** the applied pressure,the temperature increase arising from the hydrate heat in the suspension system with the optimized concentration(0.4 wt%)of GNPs was more significant than that in the traditional SDS ***,compared with those of the system without GNPs,enhanced hydration rate and storage capacity were achieved in the suspensions with GNPs,and the storage capacities were increased by 3.9%-17.0%.The promotion effect of GNPs on gas hydrate formation at low pressure is much more obvious than that at high pressure.

关键词： methane storage clathrate hydrates formation kinetics suspension graphite nanoparticles

Experimental study of bubble behaviour in a flowing liquid layer

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Experimental study of bubble behaviour in a flowing liquid l...

2020 International Conference on Nuclear engineering, ICONE 2020, collocated with the ASME 2020 power Conference

作者： Zhang, Zhengzheng Li, Liangxing Zhang, Shuanglei Saleem, Afnan State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xianning West Road 28# Xi'an city710049 China

ISBN: (纸本)9780791883785

A visualized experimental system is designed and constructed to investigate the bubble dynamic in a flowing liquid layer. Motivated by reducing uncertainties and digging a deep understand on the formation mechanism of boiling bubbles, the bubbles are formed by injecting air through a submerged orifice in our present work, where the influence of thermal physics, nucleation site density and dry spot are stripped. The water flow rate and the air flow rate are in the range of 72-324 ml/min and 0.8-2.0 ml/min, respectively. The bubble formation process in the smooth channel and the rib channel are investigated. The results state that increasing the liquid flow rates lead to the increasing bubble detachment frequency and the decreasing bubble detachment volume. Besides, the larger the liquid flow rate is, the closer the bubble center of mass is to the wall. The rib has a significant influence on the bubble formation process. In the rib channel, it is more difficult for bubbles to detach from the orifice compared that in a smooth channel. Besides, the bubble detachment volume in a rib channel is larger than it in a smooth channel. © 2020 American Society of Mechanical Engineers (ASME). All rights reserved.

关键词： Liquid films

Performance Analysis of Sco2 Tube with High Non-Uniform Heat Flux: Thermal-Fluid-Structural Evaluation and Optimization

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SSRN 2023年

作者： Gao, Shuo Wang, Yanjuan Li, Yi Liu, Qibin Xu, Jinliang The Beijing Key Laboratory of Multiphase Flow and Heat Transfer North China Electric Power University Beijing102206 China Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing100190 China University of Chinese Academy of Sciences Beijing100190 China

Supercritical carbon dioxide (sCO2) has been a promising alternative working medium in coal-fired power plants, high-temperature solar power systems, and fuel cells. In these cases, sCO2 is in a round tube under high temperature and pressure with high non-uniform heat flux (NUH). In this study, a novel structure tube is proposed to match high NUH with thermal resistance by changing tube eccentricity. A three-dimensional (3D) multiphysical coupling model was constructed to compare the novel structure with a conventional tube. The properties of fluid dynamics, thermal stress, and coupled heat transfer were analyzed. The key working parameters were discussed. The maximum temperature of the novel structure was reduced by 13–36 K, and the maximum thermal stress was reduced by approximately 25–33% under all the simulated working conditions when the eccentricity changed from 0 to 0.4. The proposed structure can reduce the maximum temperature and thermal stress effectively under high NUH. Consequently, a novel insight is presented for the design and optimization of sCO2 tube under high NUH. © 2023, The Authors. All rights reserved.

关键词： Heat transfer

Verification and validation plus uncertainty quantification of heat transfer simulation for liquid metal in wire-wrapped rod assembly

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International Communications in Heat and Mass Transfer 2025年 165卷

作者： Liu, Zhenglong Zhong, Peiling Qiu, Hanrui Wang, Mingjun Tian, Wenxi Su, Guanghui State Key Laboratory of Multiphase Flow in Power Engineering Department of Nuclear Science and Technology Xi'an Jiaotong University Xi'an710049 China

A complete CFD best practice process is proposed, including Phenomena Identification and Ranking Table (PIRT), Verification and Validation (V&V), and Uncertainty Quantification (UQ). The heat transfer of liquid metal within a rod assembly under both normal and blocked conditions is used as an example to demonstrate the full CFD process. key flow and heat transfer phenomena are identified, and model sensitivity analyses are performed based on these phenomena. Turbulent Prandtl models, porous blockage models and different meshing strategies sensitivity analysis are conducted. Uncertainty quantification is performed. The discretization uncertainty is calculated using the Grid Convergence Index (GCI). The convergence orders are greater than unity for all cases except the fluid temperature in the blocked condition using meshing strategy 2. The input parameter uncertainty is estimated using finite difference. The model uncertainty is derived. Under normal condition, the model uncertainty of the wall and fluid temperatures are 2.88 K and 3.37 K, respectively. Under blocked condition, the model uncertainty of wall temperature is slightly higher than fluid temperature. The wall temperature uncertainty for strategies 1 and 2 are 8.46 K and 9.03 K, while the fluid uncertainty of strategy 1 and 2 are 3.57 K and 3.06 K, respectively. © 2025 Elsevier Ltd

关键词： Liquid metals

pH-Triggered Hydroxylated Surface with Rapid Hydroxyl Radical Generation Boosts Efficient Noble-Metal-Free Pilot-Scale Photoreforming of Lignocellulose for Hydrogen Production

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SSRN 2023年

作者： Liu, Feng Fu, Yiwei Lu, Kejian Wang, Shujian Wang, Biao Huang, Jie Yan, Xueli Zheng, Yiqun Guo, Liejin Liu, Maochang International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Shaanxi Xi’an710049 China School of Chemistry Chemical Engineering and Materials Jining University Shandong Qufu273155 China Suzhou Academy of Xi’an Jiaotong University Jiangsu Suzhou215123 China

Photocatalytic H2 prodcution from lignocellulosic biomass photoreforming is deemed to be a promising alternative to overall water splitting owing to its more sustainable and value-added oxidation half-reaction. However, an efficient lignocellulose photoreforming system toward H2 production, especially at the pilot scale, is scarce and exigent to date. Herein, we present a lignocellulose photoreforming system containing noble-metal-free particulate twinned Cd0.5Zn0.5S nanocatalyst, water, and lignocellulose, enabling an unprecedented H2 evolution activity with an apparent quantum yield of 12.74% at 400 nm. Subsequently, an outdoor 7.2-m2 compound parabolic concentrator-based reactor is developed to scale up this system to a practical level with a H/2 production rate of 615 mL h-1 under direct solar irradiation. We demonstrate that a pH-triggered hydroxylated surface over Cd0.5Zn0.5S nanotwins enables superior hole transfer and rapid hydroxyl radical generation by inducing favorable reaction kinetics/thermodynamics in alkaline solution. Our work thus provides a state-of-art example of pilot-scale system for the practical Hsub>2 production via lignocellulose photoreforming. © 2023, The Authors. All rights reserved.

关键词： Lignocellulose

Corrosion Behavior of Low Carbon 9cr-Ods Steel in High Temperature Oxygen-Saturated Lead-Bismuth Eutectic

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SSRN 2024年

作者： Yang, Chongdou Xu, Yuwen Yun, Di Zhao, Bingyao Liu, Wenguan Gao, Rui Xie, Shijing Qiu, Jie School of Nuclear Science and Technology Xi’an Jiaotong University Xi’an710049 China State Key Laboratory of Multiphase Flow Xi’an Jiaotong University Xi’an710049 China Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen University Zhuhai519082 China

The corrosion behavior of low-carbon 9Cr-ODS steel were carried out in oxygen saturated LBE. It was found that the thickness of the oxide film increased with increasing corrosion time, but the growth rate gradually slows down with increasing time. TEM and XRD results show that the main structure of the oxide layer formed on 9Cr-ODS steel is multilayered structure, consist of an (Fe,Cr)3O4 spinel inner layer, mixed with some nano precipites FeCr2O4, Cr3O4, Mn3O4 and morphous at the grain boundaries, nanocrystal transition layer and a Fe3O4 outer layer. The corrosion mechanism of 9Cr-ODS steel in liquid LBE is discussed. © 2024, The Authors. All rights reserved.

关键词： Manganese oxide

A New Structure Tube for Supercritical Co 2 Turbulent flow with High Non-Uniform Heat Flux

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SSRN 2023年

作者： Wang, Yanjuan Gao, Shuo Shi, Weijie Liu, Qibin Xu, Jinliang The Beijing Key Laboratory of Multiphase Flow and Heat Transfer North China Electric Power University Beijing102206 China Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing100190 China University of Chinese Academy of Sciences Beijing100190 China

Supercritical carbon dioxide (sCO2) has been a promising alternative working medium in coal-fired power plants, high-temperature solar power systems, and fuel cells. In these cases, sCO2 is in a round tube under high temperature and pressure with high non-uniform heat flux (NUH). In this study, a novel structure tube is proposed to match high NUH with thermal resistance by changing tube eccentricity. A three-dimensional (3D) multiphysical coupling model was constructed. The novel structure can reduce Tmax and T effectively for the half-cycle uniform heat flux (HUH) and NUH cases. The maximum thermal stress decreased by 23 and 29% and Tmax decreased by 29.6 K and 24.8 K for HUH and NUH cases when Ec increased from 0 to 0.4. A comparison was made between the proposed structure, thin-walled tube, and traditional tube. Results showed that the performance of the proposed tube is the best. Tmax decreases by approximately 55 K compared with the traditional and thin-walled tubes. σeq,max of the eccentric tube is the smallest. Furthermore, the structure will facilitate the safety and economics of the tube. Consequently, a novel insight is presented for the design and optimization of sCO2 tube under high NUH. © 2023, The Authors. All rights reserved.

关键词： Heat transfer