检索结果-内蒙古大学图书馆

Research of Cooling Tower Filler Based on Radial Basic Function Artificial Neural Network (Rbf Ann)

学校读者我要写书评

暂无评论

SSRN 2022年

作者： Chen, Jie Zhang, Lixin Zhao, Shunan Chen, Yongbao Song, Huijuan Liu, Jingnan Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai200093 China China Institute of Water Resources and Hydropower Beijing100038 China

The filler is the core component of a cooling tower for heat dissipation. The empirical formulas of N, β xv , and ΔP are constitute the performance of filler. In certain conditions, the formulas are obtained by experiments. Performance equations for identical countercurrent fillers are different at varying heights or seawater concentrations. The conventional method is linear interpolation to obtain the filler performance under different conditions. But its uncertainty limits the application of the performance equation to some extent. Therefore, the RBF ANN is adopted to analyze the filler performance based on the existing performance equations in this paper. The dataset is generated by the filler performance equations. The results show that RBF ANN has a preferable prediction effect of filler performance with high correlation (R>0.99) and prediction accuracy (N 10 >90%). In addition, the trend of the predicted results and the experimental results of the filler performance is consistent. Therefore, RBF ANN can accurately predict the filler performance at different heights and different seawater concentrations, which provides the basis for the design of cooling towers. © 2022, The Authors. All rights reserved.

关键词： Cooling towers

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

学校读者我要写书评

暂无评论

SSRN 2023年

作者： Machado, Danilo Almeida Costa, Fernando S. 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

Hydrothermal Hydrolysis Modeling of Lignocellulosic Biomass Using Subcritical Water for Test Packed Bed Reactor

学校读者我要写书评

暂无评论

SSRN 2023年

作者： Wu, Zhonggang Wang, Jiawei Du, Xiaocheng Su, Hanguang China Nuclear Power Operations Co. Ltd. Shenzhen518116 China Department of Mathematics Physics and Electrical Engineering Northumbria University NewcastleNE1 8ST United Kingdom State Key Laboratory of Multiphase Flow in Power Engineering Xian Jiaotong University Xi'An China School of Information Science and Engineering Northeastern University Shenyang China

In this paper, the subcritical water hydrothermal conversion process of lignocellulosic biomass as porous media in packed bed reactor was investigated by numerical simulation. The computational fluid dynamics mathematical modeling was used to describe the transient multi-physical fields formed during the instantaneous formation process of organic functional groups on the bases of experiment. The effect of inlet hydrothermal fluid velocity and temperature on the transient seepage flow, heat and transfer, and organic conversion reaction were investigated by ANSYS FLUENT® software. The results of the simulation indicate that the osmotic pressure and velocity increase with the hydrothermal fluid velocity and temperature. The surface heat transfer coefficient increases with the hydrothermal fluid velocity and temperature, and may reach the maximum within the scope of this paper. Both experimental and numerical simulation results consistently show that within the first 60 minutes of the hydrothermal reaction, the organic reaction rate is mainly determined by the combined model of turbulent-hydrothermal reaction. For a later time period after 60 minutes, the organic reaction rate mainly depends on the single model of hydrothermal reaction. Comparing the same experimental conditions and their real-time measurements, the numerical results in this paper accord with them. © 2023, The Authors. All rights reserved.

关键词： Porous materials

Simultaneous Analysis of Swirl Spray Dynamics Using a Telecentric System

学校读者我要写书评

暂无评论

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

关键词： Liquid films

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

学校读者我要写书评

暂无评论

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

学校读者我要写书评

暂无评论

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

学校读者我要写书评

暂无评论

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

学校读者我要写书评

暂无评论

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

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

学校读者我要写书评

暂无评论

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