检索结果-内蒙古大学图书馆

Corrosion Effect Analysis on Thermal-Hydraulics of Lbe/Water Spiral Tube Steam Generator Under Oxygen-Controlled Environment

学校读者我要写书评

暂无评论

SSRN 2023年

作者： Lu, Dingsheng Yang, Yupeng Wang, Chenglong Zhang, Dalin Qiao, Pengrui Tian, Wenxi Qiu, Suizheng Su, Guanghui H. School of Nuclear Science and Technology Shanxi Key Laboratory of Advanced Nuclear Energy and Technology Xi'an Jiaotong University Xi'An710049 China China Institute of Atomic Energy Beijing102413 China State Key Laboratory of Multiphase Flow in Power Engineering China

In order to explore the flow and heat transfer characteristics of spiral tube steam generators under Lead-Bismuth Eutectic (LBE) corrosion, the accelerated removal effect of LBE corrosion flow was perfected, and a bidirectional coupling model of LBE corrosion and flow heat transfer was established. Computational fluid dynamics (CFD) method was used to simulate the corrosion and flow heat transfer of helical tube steam generator under saturated oxygen concentration and oxygen-controlled environment. The results indicate that the corrosion of liquid LBE forms an oxidation layer, which hinders the heat transfer in the spiral tube steam generator. This leads to a significant increase in the wall friction coefficient and a decrease in the surface Nusselt number. However, it does not have a significant effect on the water side evaporation process of the spiral tube steam generator. The implementation of an oxygen-controlled environment can effectively reduce the influence of LBE corrosion on the flow heat transfer of the spiral tube steam generator. Especially under high temperature conditions, it can reduce the near wall temperature of LBE change by up to 57.5% and the outlet temperature change by up to 61.5%. The oxygen-controlled environment results in prolonged local hypoxia time, with a more pronounced effect at higher temperatures. © 2023, The Authors. All rights reserved.

关键词： Oxygen

Data Mining-Assisted Multi-Objective Optimization of Blade Angle Distributions for Efficiency and Stability Enhancement of a Free-Form Centrifugal Impeller

学校读者我要写书评

暂无评论

SSRN 2024年

作者： Chen, Zhikai Chen, Ziying Sun, Jieshuai Guo, Yi Spence, Stephen Peng, Xueyuan Feng, Jianmei School of Energy and Power Engineering Xi'an Jiaotong University Xi’an710049 China School of Mechanical Manufacturing and Biomedical Engineering Trinity College Dublin Dublin 2 Ireland State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi’an710049 China

The design optimization process for a centrifugal compressors faces significant trade-offs between efficiency, pressure ratio, and stable operating range. To address this challenge, a data mining assisted-optimization combining machine learning modelling method and non-dominated sorting genetic algorithm III (NSGA-III) has been proposed to enhance efficiency and pressure ratio while considering expansion of operational stability. A validated CFD numerical model was established for data generation. A Light-GBM model with Bayesian hyperparameter tuning and a deep feedforward neural network (DNN) model were constructed, and the better one was selected for performance prediction. Data mining techniques, including Sobol sensitivity analysis and SHAP, were employed to identify the key sensitive parameters and their interactions. Finally, a NSGA-III-based multi-objective optimization was conducted to determine the optimal geometry of the free-form surface impeller. Results showed that the blade angle distributions at the leading edge of mid-span and shroud profile were the most sensitive parameters affecting isentropic efficiency at the design point, with their recommended ranges identified. The optimized impeller has an increase in total pressure ratio of 2.98% and isentropic efficiency of 0.67% at the design point, especially exhibiting excellent aerodynamic performance at higher mass flow rate conditions. The maximum improvements of total pressure ratio and isentropic efficiency were 12.91% and 9.53%, respectively, corresponding to the near choke mass flow rate at the design speed. Additionally, operating stability was expanded with a 1.22% increase in total pressure ratio at near surge mass flow rate at the design speed, which contributed to a delay in the onset of surge. © 2024, The Authors. All rights reserved.

关键词： Sensitivity analysis

Free surface vortex in a rotating barrel with rods of different heights

学校读者我要写书评

暂无评论

International Journal of Fluid Machinery and Systems 2016年第4期9卷 325-331页

作者： Zhang, Xiaoyue Zhang, Min Chen, Wanyu Yang, Fan Guo, Xueyan School of Energy and Power Engineering University of Shanghai for Science and Technology No. 516 Jungong Road Shanghai200093 China Department of Mechanical and Electrical Engineering Henan Mechanical and Electrical Engineering College No. 699 Pingyuan Road Xinxiang453003 China Key Laboratory of Flow Control and Simulation University of Shanghai for Science and Technology No. 516 Jungong Road Shanghai200093 China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering No. 516 Jungong Road Shanghai200093 China

A bathtub vortex above the outlet of a rotating barrel is simulated. By analyzing the Ekman layer theory, it can be found that the main flow circulation is inversely proportional to the thickness of Ekman layer. The thicker the Ekman boundary layer, the weaker the rotational strength and the shorter of the length of gas core is. According to this law, models of barriers with rods of different heights are established. The reduction of air-core length in this air entrainment vortex and weakening the strength of rotation field were achieved. © 2016 Turbomachinery Society of Japan. All rights reserved.

关键词： Vortex flow

Editor, Applied Energy Paper Entitled: "Industrialized Bimetallic Nano Oxygen Carrier for Dual-Stage Hydrogen Production from Mid-Temperature Chemical Looping Reforming"

学校读者我要写书评

暂无评论

SSRN 2024年

作者： Tang, Sanli Gai, Zhongrui Li, Yang Liu, Yunlian Liu, Mingkai Pan, Ying Jin, Hongguang Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing100190 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China University of Chinese Academy of Sciences Beijing100049 China

Chemical looping methane reforming has emerged as a promising avenue to produce blue hydrogen. Among the various oxygen carriers investigated for this process, Fe2O3 and NiO have garnered significant attention due to their affordability and favorable thermodynamic properties. Usually, such oxygen carriers had satisfactory H2 yields only in the oxidation stage with temperatures over 800 °C. This limitation poses challenges for industrial reactor design and product gas separation. In this study, we present a nanoscale Fe/Ni bimetallic oxygen carrier for dual-stage hydrogen generation from mid-temperature chemical looping methane reforming. The lab-scale oxygen carrier can produce H2 in both the reduction and the oxidation steps, reaching 75% overall H2 purity while reducing the temperature to 500-600 °C. Moreover, the 10-kg scale oxygen carrier achieved >90% CH4 conversion, >78% H2 purity and 2.8-3.5 H2 molecules produced per CH4 molecule. Made into beads, the 10-kg scale oxygen carrier still maintained an outlet H2 purity of >70% with redox stability over 150 cycles. These findings contribute to the advancement of chemical looping methane reforming for blue hydrogen production and supply. © 2024, The Authors. All rights reserved.

关键词： Hydrogen production

fEffect of alkali and alkaline metals on gas formation behavior and kinetics during pyrolysis of pine wood

学校读者我要写书评

暂无评论

Fuel 2021年 290卷

作者： Li, Jinhu Burra, Kiran G. Wang, Zhiwei Liu, Xuan Gupta, Ashwani K. The Combustion Laboratory Department of Mechanical Engineering University of Maryland College ParkMD20742 United States Faculty of Engineering China University of Geosciences WuhanHubei430074 China College of Environmental Engineering Henan University of Technology Zhengzhou450001 China State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Xi'an710049 China

This study examines the acid and alkaline treatment of pine wood to help understand the effect of alkali and alkaline earth metals (AAEMs) content on the pyrolysis behavior at different temperatures. Acid and alkali pretreatment of pine wood were conducted to modify AAEMs content by ion-exchanging method. Thermal kinetic behavior of the pretreated samples was first conducted by a thermogravimetric analyzer (TGA) at different heating rates that provided activation energies of pyrolysis. Gas formation behavior of the samples for different extents of conversion was carried out in a fixed-bed reactor at two different temperatures of 823 K and 1073 K. Evolutionary behavior of the gas components during pyrolysis, including flow rate, and yield and their energy content were measured and compared. Results showed that the values of activation energies increased with the extent of conversion for all the pretreated samples examined. The effect of AAEMs on pyrolysis behavior of biomass varied with the extent of conversion. The presence of AAEMs in biomass decreased the decomposition energy at low conversion while it greatly improved under high conversion. Besides, alkali treated sample with higher AAEM content enhanced the gas and char yield while it reduced the bio-oil production at low temperature with low conversion. However, at high temperature the opposite trend was observed. Presence of AAEMs was favorable for the generation of H2, CO, CO2 and CnHm at low temperature, while it showed an inhibition effect on CO and CnHm yield and syngas energy at high temperature. The catalytic mechanism of AAEMs on the pyrolysis behavior at different temperatures was discussed based on activation energy and gaseous formation. Results revealed decomposition of carboxylate at low temperature and formation of stable biomass-Na (BM-Na) structure at high temperature that led to the variation of activation energy and changed gaseous products yield and syngas energy. Acid washing pretreatment wa

关键词： Activation energy

Conducting Polymers Meet Lithium-Sulfur Batteries:Progress,Challenges,and Perspectives

学校读者我要写书评

暂无评论

Energy & Environmental Materials 2023年第5期6卷 159-182页

作者： Xin Chen Chengcheng Zhao Kai Yang Shiyi Sun Jinxin Bi Ningrui Zhu Qiong Cai Jianan Wang Wei Yan Department of Environmental Science and Engineering State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong UniversityXi'an 710049China Xi'an Key Laboratory of Solid Waste Recycling and Resource Recovery Department of Environmental EngineeringXi'an Jiaotong UniversityXi'an 710049China Advanced Technology Institute University of SurreyGuildfordSurrey GU27XHUK College of Arts College of Landscape Architecture Fujian Agriculture and Forestry UniversityFuzhou 350108China Department of Chemical&Process Engineering Faculty of Engineering and Physical Sciences University of SurreyGuildford GU27XHUK

Lithium-sulfur(Li-S)batteries have attracted increased interest because of the high theoretical energy density,low cost,and environmental *** polymers(CPs),as one of the most promising materials used in Li-S batteries,can not only facilitate electron transfer and buffer the large volumetric change of sulfur benefiting from their porous structure and excellent flexibility,but also enable stronger physical/chemical adsorption capacity toward polysulfides(LiPSs)when doped with abundant heteroatoms to promote the sulfur redox kinetics and achieve the high sulfur *** review firstly introduces the properties of various CPs including structural CPs(polypyrrole(PPy),polyaniline(PANi),polyethylene dioxothiophene[PEDOT])and compound CPs(polyethylene oxide(PEO),polyvinyl alcohol(PVA)and poly(acrylic acid)[PAA]),and their application potential in Li-S ***,the research progress of various CPs in different components(cathode,separator,and interlayer)of Li-S batteries is systematically ***,the application perspective of the CPs in Li-S batteries as a potential guidance is comprehensively discussed.

关键词： conducting polymers Li-S batteries modified materials polysulfides

金属原子诱导的微环境调控在聚合氮化碳光催化析氢中的研究

学校读者我要写书评

暂无评论

Science China Materials 2024年第6期67卷 1765-1779页

作者：赵大明杨雨骁 Vasileios Binas 沈少华 School of Advanced Energy Shenzhen Campus of Sun Yat-sen UniversityShenzhen 518107China International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityXi’an 710049China Institute of Electronic Structure and Laser(IESL) Vasilika VoutonHeraklion GR-71110Greece Physical Chemistry Laboratory Chemistry DepartmentAristotle University of ThessalonikiThessaloniki 54124Greece

开发高效稳定的半导体光催化剂对光催化技术迈向实际应用至关重要.聚合物氮化碳(CN)因其优异的物理化学性质而被视为最具发展前景的制氢光催化剂之一.在过去几十年中,从热力学或动力学角度开发的一系列改性策略已经显著提升了CN的光催... 详细信息

开发高效稳定的半导体光催化剂对光催化技术迈向实际应用至关重要.聚合物氮化碳(CN)因其优异的物理化学性质而被视为最具发展前景的制氢光催化剂之一.在过去几十年中,从热力学或动力学角度开发的一系列改性策略已经显著提升了CN的光催化制氢性能.近期,金属原子修饰策略为CN改性提供了一条新途径,这种策略可以精确调控CN的微环境.本文全面回顾了金属原子修饰的CN光催化剂在光催化分解水制氢领域的最新研究进展,包括金属单原子修饰的CN、金属双原子修饰的CN、金属单原子与团簇共修饰的CN,重点阐述了金属原子对提升光催化性能的关键作用.此外,本文还全面总结了发展先进的金属原子修饰的CN光催化剂所面临的挑战与机遇.

关键词： metal atom polymeric carbon nitride hydrogen evolution photocatalysis solar energy conversion

Characteristics of Bubble Dynamic Behavior on the Surface of Photoelectrode Under the Influence of a Vertical Magnetic Field

学校读者我要写书评

暂无评论

SSRN 2023年

作者： Feng, Yuyang Wang, Yechun Zhang, Bo Cao, Zhenshan Liu, Miaomiao Zhen, Canghao Guo, Liejin State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Xinjin Weihua Institute of Clean Energy Research Nanhai District Guangdong Province Foshan City China

The magnetohydrodynamic (MHD) flow around the bubble induced by the Lorentz force owing to the applied magnetic field significantly affects the behavioral characteristics of the bubble on the electrode surface. However, the mechanism of the impact of a magnetic field perpendicular to the electrode on the dynamic behavior of bubbles remains unclear. In this study, the evolution law of a single oxygen bubble on the surface of a TiO2 photoelectrode under the influence of a vertical magnetic field with different magnetic induction intensities was investigated. The vertical magnetic field effectively promoted the rapid detachment of bubbles from the electrode surface, and greatly improved the gas evolution efficiency. The mass transfer was dominated by single-phase free convection during bubble evolution. Under the influence of the vertical magnetic field, the mass transfer coefficient near the electrode was enhanced, and the adverse effects of bubbles on mass transfer were counteracted when they entered the reaction-controlled growth phase. The further multiphysics simulation found that the MHD convection decreased the local supersaturation of reaction product oxygen molecules near the electrode, thereby reducing concentration overpotential and increasing the reaction rate. This study provides an experimental and theoretical basis for promoting the bubble detachment and the reaction rate on the gas evolving electrode surface during photoelectrochemical water splitting. © 2023, The Authors. All rights reserved.

关键词： Efficiency

Solution chemistry back‐contact FTO/hematite interface engineering for efficient photocatalytic water oxidation

学校读者我要写书评

暂无评论

Chinese Journal of Catalysis 2022年第5期43卷 1247-1257页

作者： Karen Cristina Bedin Beatriz Mouriño Ingrid Rodríguez-Gutiérrez João Batista Souza Junior Gabriel Trindade dos Santos Jefferson Bettini Carlos Alberto Rodrigues Costa Lionel Vayssieres Flavio Leandro Souza The National Nanotechnology Laboratory(LNNANO) Brazilian Center for Research in Energy and Materials(CNPEM)Campinas 13083‐970Brazil Centro de Ciências Naturais e Humanas(CCNH) Federal University of ABC(UFABC)Santo André09210580Brazil Federal University of Rio Grande do Sul(UFRGS) Rio Grande do SulBrazil International Research Center for Renewable Energy(IRCRE) State Key Laboratory of Multiphase Flow in Power EngineeringSchool of Energy and Power EngineeringXi’an Jiaotong UniversityXi’an 710049ShaanxiChina

This work describes a simple yet powerful scalable solution chemistry strategy to create back‐contact rich interfaces between substrates such as commercial transparent conducting fluorine‐doped tin oxide coated glass(FTO)and photoactive thin films such as hematite for low‐cost water oxidation ***‐resolution electron microscopy(SEM,TEM,STEM),atomic force microscopy(AFM),elemental chemical mapping(EELS,EDS)and photoelectrochemical(PEC)investigations reveal that the mechanical stress,lattice mismatch,electron energy barrier,and voids between FTO and hematite at the back‐contact interface as well as short‐circuit and detrimental reaction between FTO and the electrolyte can be alleviated by engineering the chemical composition of the precursor solutions,thus increasing the overall efficiency of these low‐cost photoanodes for water oxidation reaction for a clean and sustainable generation of hydrogen from PEC water‐*** findings are of significant importance to improve the charge collection efficiency by minimizing electron‐hole recombination observed at back‐contact interfaces and grain boundaries in mesoporous electrodes,thus improving the overall efficiency and scalability of low‐cost PEC water splitting devices.

关键词： Nanostructure Iron oxide Water oxidation Photoanode Surface engineering Chemical synthesis