检索结果-内蒙古大学图书馆

Understanding the Reversal Dilution Effect of the Species Sampling in the Negative Temperature Coefficient Region

学校读者我要写书评

暂无评论

SSRN 2023年

作者： Wu, Yingtao Mai, Zhaoming Rao, Boxuan Liu, Jie Tang, Chenglong Huang, Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi'An710049 China Department of Power Mechanical Engineering Beijing Jiaotong University Beijing100044 China

Species sampling during fuel autoignition can provide valuable insights in studying the chemical kinetic mechanism. Various species sampling techniques have been developed for speciation quantification in different reactors. However, unavoidable dilution in the physical sampling brings uncertainty to the measurements, particularly in the negative temperature coefficient (NTC) region where the effect of dilution remains unclear. To address this issue and improve measurement accuracy, numerical species samplings during the autoignition of n-butane mixture were studied in a rapid compression machine reactor. Results show that greater fuel consumption and intermediate generation were observed in regions with lower temperatures instead of the hot core zone. Therefore, the dilution effect on the sampling results is reversed inside the NTC region. Furthermore, results from two typical sampling methods were compared with the target core profiles to determine their uncertainties. Lastly, the feasibility of applying dilution ratio calibration on the sampling results in the NTC region was tested, which indicates the necessity of considering the NTC effect, particularly for intermediates with low concentrations. Alternatively, increasing the sampling duration of the fast-sampling method effectively reduces the uncertainty of species concentration and enhances the robustness of mechanism validation regardless of the NTC behavior. © 2023, The Authors. All rights reserved.

关键词： Temperature

A Comprehensive Review on Multi-Dimensional Heat Conduction of Multi-Layer and Composite Structures:Analytical Solutions

学校读者我要写书评

暂无评论

Journal of Thermal Science 2021年第6期30卷 1875-1907页

作者： AMIRI DELOUEI Amin EMAMIAN Amin SAJJADI Hasan ATASHAFROOZ Meysam LI Yueming WANG Lian-Ping JING Dengwei XIE Gongnan Department of Mechanical Engineering University of BojnordBojnordIran Mechanical Engineering Department Shahrood University of TechnologyShahroodIran Department of Mechanical Engineering Siijan University of TechnologySiijanIran School of Aerospace Engineering Xi’an Jiaotong UniversityXi’an 710049China Guangdong Provincial Key Laboratory of Turbulence Research and Applications Center for Complex Flows and Soft Matter Research and Department of Mechanics and Aerospace EngineeringSouthern University of Science and TechnologyShenzhen 518055China Department of Mechanical Engineering University of DelawareNewarkDelaware19711USA International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityXi’an 710049China Department of Mechanical and Power Engineering Northwestern Polytechnical UniversityXi'an 710072China

Heat conduction in multi-layer and composite materials is one of the fundamental heat transfer problems in many industrial *** to different materials types,interface conditions,and various geometries of these laminates,the heat conduction mechanism is more complicated than that of one-layer isotropic *** solutions are the best ways to study and understand such problems in *** this study,different existing analytical solutions for heat conduction in multi-layer and composite materials are reviewed and classified in rectangular,cylindrical,spherical,and conical *** boundary conditions,internal heat source,and thermal contact resistance as the most critical parameters in the solution complexity investigated in the literature,are discussed and summarized in different *** types of multi-layer structures such as isotropic,anisotropic,orthotropic,and reinforced laminates are included in this *** is found that although more than half a century has passed since the beginning of the research on heat transfer in multi-layer composites,new researches that can help with a better understanding in this area are still being *** challenges and shortcomings in this area are also discussed to guide future researches.

关键词： multi-dimensional heat conduction composite laminates multi-layer structures analytical solutions interface contact resistance

Sub- and Supercritical Water Flooding for Enhanced Oil Recovery in High Water Cut Heavy Oil Reservoirs: An Experimental Study

学校读者我要写书评

暂无评论

SSRN 2024年

作者： Miao, Yan Zhao, Qiuyang Huang, Zujie Zhao, keyu Zhao, Hao Guo, Liejin Wang, Yechun State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Xinjin Weihua Institute of Clean Energy Research Foshan528216 China

High water cut poses a formidable challenge for heavy oil reservoirs, necessitating a strategy to enhance oil recovery. This study introduces a green-efficient approach - Supercritical Water Flooding (SCWF), suitable for sandstone heavy oil reservoirs with high water cut, compared to conventional subcritical water flooding and steam flooding. A novel experimental system (450°C,30MPa) was established to conduct SCWF experiments for heavy oil from Shengli Oilfield. The results showed that SCWF at 400°C and 25MPa had the recovery factor of 96.27% and the viscosity reduction rate of 61.6% for GD heavy oil. The dynamic process of SCWF is divided into three stages: pressure rising drainage stage, heating and depressurization stage, and miscible flooding stage. Analysis indicates that the high diffusivity, solubility and reactivity of supercritical water make thermal fluid breakthrough, miscible flooding and aquathermolysis reactions become the key mechanisms for high oil recovery and in situ upgrading of SCWF for high water cut heavy oil reservoirs. © 2024, The Authors. All rights reserved.

关键词： Crude oil

Proposal and thermodynamic analysis of a steam methane reforming system integrated with thermochemical energy storage and a SCO2 brayton cycle

学校读者我要写书评

暂无评论

Journal of Energy Storage 2025年 127卷

作者： Fu, Yu Liu, Ming Wang, Zhu Xie, Tao Yan, Junjie State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China Institute of Industrial Catalysis School of Chemical Engineering and Technology Xi'an Jiaotong University Xi'an710049 China

Solar energy is a promising alternative to fossil fuels for providing heat in steam methane reforming (SMR) hydrogen production. However, the variability of solar energy requires effective storage solutions. This study presents a new SMR hydrogen production system that integrates thermochemical energy storage (TCES) utilizing a CaO/CaCO3 cycle with a SCO2 Brayton cycle. The system converts fluctuating solar energy into the stable chemical energy of CaO by calcinating CaCO3 in the solar calciner, with the SMR reaction mainly heated by the exothermic reaction of CaO and CO2. The SCO₂ Brayton cycle efficiently recovers heat from the high-temperature SMR products. Comprehensive thermodynamic analysis and evaluation models are developed. Results show that the proposed system performs well, achieving energy and exergy efficiencies of 73.49 % and 78.46 %, respectively, under benchmark conditions. The energy storage efficiency of TCES is 81.55 %, and the solar-to-chemical energy efficiency is 48.21 %. Integrating TCES significantly enhances the system's steady operation under fluctuating solar energy conditions. The calciner accounts for the largest share of exergy destruction at 31.63 %, followed by the carbonator at 17.50 %. Sensitive analyses of key operating parameters indicate that higher CaO conversion rate and storage temperature enhance energy storage, energy, and exergy efficiencies. Besides, the energy and exergy efficiencies decrease with the increasing SMR reaction pressure but increase with rising reaction temperature. When the S/C is 2.0, these efficiencies reach their maximum values of 75.42 % and 78.63 %, respectively. © 2025 Elsevier Ltd

关键词： Brayton cycle

Room-temperature photodeposition of conformal transition metal based cocatalysts on BiVO4 for enhanced photoelectrochemical water splitting

学校读者我要写书评

暂无评论

Nano Research 2020年第1期13卷 231-237页

作者： Lu Wang Tao Zhang Jinzhan Su Liejin Guo International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringSchool of Energy&Power EngineeringXi’an Jiaotong UniversityXi’an710049China

Photoelectrochemical(PEC)water splitting using semiconductors offers a promising way to convert renewable solar energy to clean hydrogen ***,due to the sluggish reaction kinetics of water oxidation,significant charge recombination occurred at the photoanode/electrolyte interface and cause decrease of its PEC *** reduce the surface recombination,we deposit different transition metal complexes on BiVO4 nanocone arrays by a versatile light driven in-situ two electrode photodeposition approach without applied *** cobalt phosphate“Co-Pi”,nickel borate“Ni-Bi”and manganese phosphate“Mn-Pi”complexes were deposited on BiVO4 nanocone arrays to form core-shell structure photoanode,all of which lead to enhanced photoelectrochemical *** photocurrent of the Co-Pi/BiVO4 photoanode under front-side illumination for 5 min is increased by 4 folds comparing to that of bare BiVO4 photoanode at 0.6 V ***,reaching a hole transfer efficiency as high as 94.5%at 1.23 V *** proposed photodeposition strategy is simple and efficient,and can be extended to deposite cocatalyst on other semiconductors with a valence band edge located at a potential more positive than the oxidation potential of transition metal ion in the cocatalyst.

关键词： bismuth vanadate photoelectrochemcial water splitting conformal photodeposition cocatalyst

Pilot-Scale Photoreforming of Hydrolyzed Polylactic Acid Waste to High-Value Chemicals and H2 via Atomic Ru Integration

学校读者我要写书评

暂无评论

Advanced Energy Materials 2025年第0期

作者： Liu, Feng Zhang, Chunyang Lu, Kejian Yan, Xueli Wang, Yi Jing, Dengwei 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 Suzhou Academy of Xi'an Jiaotong University Jiangsu Suzhou215123 China

Photoreforming of polylactic acid (PLA) waste into valuable chemicals offers a promising approach for environmental protection and waste valorization, yet faces challenges of low yields and harsh conditions. Herein, a Cd0.5Zn0.5S nanotwin catalyst decorated with Ru single atoms and clusters is reported, enabling selective photoreforming of PLA into pyruvic acid (PA) and H2. It is demonstrated that Ru single atoms favor PA formation via hydroxyl dissociation, while the further incorporation of Ru clusters serve as active sites for H2 production. This synergistic effect significantly enhances photocatalytic performance, achieving 96.8% PA selectivity and efficient H2 production with a record-breaking apparent quantum efficiency of 83.7% at 400 nm. This approach is scalable for outdoor processes, utilizing direct 1 m2 sunlight irradiation to deliver ≈1191 mL h−1 of H2 and 47.27 mmol h−1 of PA from PLA waste, paving a viable pathway for large-scale simultaneous production of high-value chemicals and H2. © 2025 Wiley-VCH GmbH.

关键词： Photolysis

Simulation Study on the Dynamic Characteristics of Natural Circulation Coupled Phase Change Material for Equal Height Difference Passive Containment Cooling System

学校读者我要写书评

暂无评论

SSRN 2024年

作者： Chen, Weixiong Huang, Yufan Wang, Han Yang, Xiaohu Li, Shaodan Zhao, Quanbin Chong, Daotong State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Wuhan Second Ship Design and Research Institute Wuhan430205 China

The passive containment cooling system (PCCS) plays a significant role in ensuring the safety of nuclear power plants. To further reduce peak pressure in the containment during a loss of coolant accident (LOCA), phase change materials (PCMs) are utilized to improve the system’s cooling effectiveness. The dynamic simulation model of PCCS has been developed using Apros software. This article focuses on examining the system’s dynamic characteristics related to various tube startup methods and comparatively analyzing the impact of different PCM thicknesses on heat transfer capacity. The results indicate that post-accident, PCM significantly suppresses peak pressure in the containment. Under the full tube startup method with 4 mm PCM, the peak pressure decreases to 1.75 MPa, whereas under the empty tube startup method, it is reduced to 1.69 MPa. With natural circulation empty tube startup method, PCM can reduce pressure change intensity in the containment but negatively affects natural circulation heat transfer. Although the full tube startup method underperforms the empty tube startup method on suppressing peak pressure, PCM can positively affect natural circulation heat transfer in the early stages of the accident. Empty tube startup offers the advantages of higher heat transfer capacity and lighter weight, making it the optimal choice for ocean nuclear platforms. Additionally, the higher peak power of PCM heat transfer under the empty tube startup method indicates that system can withstand larger thermal shocks. © 2024, The Authors. All rights reserved.

关键词： Thermoelectric equipment

Hydrothermal pretreatment of protein-rich substrate:Modified physicochemical properties and consequent responses in its anaerobic digestion

学校读者我要写书评

暂无评论

Carbon Resources Conversion 2023年第1期6卷 1-10页

作者： Fa Qiao Guangyi Zhang Jie Fan Hang Zhang Bowen Shi Jiancheng Yang Jianling Zhang Zhennan Han Shenyang University of Chemical Technology Shenyang 110142Liaoning ProvinceChina School of Ecology and Environment Beijing Technology and Business UniversityBeijing 100048China State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China School of Urban Construction Wuhan University of Science and TechnologyWuhan 430081Hubei ProvinceChina China Power Engineering Consulting Group Co. LtdBeijing 100120China

Wasted tofu rich in protein was subject to hydrothermal pretreatment(HTPT)under different conditions(at 120,140,160 and 180℃;for 0,30,60 and 90 min)followed by biochemical methane potential(BMP)tests,and 140℃and 0 min were found to be respectively the best temperature and duration for HTPT of tofu in terms of its biogas *** the under the optimal conditions(140℃,0 min)the accumulative methane yield reached up to 510.9 mL⋅(gVS)-1,which was 26.98%higher than that without HTPT(402.3 mL⋅(gVS)-1).The start-up process of continuous anerobic digestion(AD)of the tofu before and after hydrothermal treated(HT)at the optimal HTPT conditions(140℃,0 min)was examined,to investigate and compare how their consequent AD responded to *** was found that,for start-up of continuous AD,the HT tofu delivered more balanced nutrients and thus led to more stable AD and quicker biogas ***,HTPT generated products refractory to biodegradation,to slightly decrease the total biogas *** AD of HT tofu some weak ammonia-tolerant microbes,such as methylotrophic methanogens,survived and played indispensable *** of living microbial community structure indicated that,some hydrolytic acidification bacteria intolerant to ammonia nitrogen(such as Proteobacteria)were always active and appeared at high *** viable methylotrophic methanogens,*** M2,took obvious responsibilities in start-up of the AD for HT tofu.

关键词： Hydrothermal pretreatment(HTPT) Protein-rich substrate Anaerobic digestion(AD) Biogas Microbial community structure

Alkaline Pulping Catalyzed Ordered Conversion of Bark in Supercritical Water

学校读者我要写书评

暂无评论

SSRN 2023年

作者： Ge, Hui Huang, Yong Liu, Zhaozheng Liu, Fan Chen, Yu-Nan Guo, Liejin State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University No.28 Xianning West Road Xi’an710049 China

The hydrophilicity of lignocellulosic biomass hinders the application of a high concentration slurry for supercritical water gasification, thereby reducing the efficiency of gasification and energy self-sufficiency. A pretreatment method of alkaline pulping with KOH and NaOH was proposed considering initial pressure to prepare high concentration slurry. In this study, bark as lignocellulosic biomass specimen, whose 30wt% and 40wt% slurries, with favorable rheology and stability, was prepared via alkaline pulping successfully. The most economical conditions were 180 °C and 24% KOH addition. The bark macromolecules were restructured due to the hydrolysis of cellulose and lignin by breaking down the hydrogen bond and ether bond with trivial hydrocarbon matrix loss. The scattered crystal growth being created and a reduction of hydrophilic groups facilitated the uniform premixing of bark and water, which is improved by a stable charge system furtherly. Additionally, metal ions could be deposited onto the bark surface during alkaline pulping. The chemical modification leading by alkaline pulping achieved the premixing of feedstock and water to form bark slurry. The conversion barrier was decreased to fulfill the ordered conversion. Consequently, the commendable catalytic effect of 95.66% gasification efficiency was displayed for 40wt% bark slurry with trivial coke yield. The functional groups of organic matter in the slurry were significantly converted into the gas phase, and lattice oxygen was produced in the solid product. The maximum alkali recovery of 80% was achieved at 580 °C. The successful completion of this research affirms the dominance of the pulping-alkali recovery-gasification method for expanding the application of SCWG of lignocellulosic biomass in large engineering projects. © 2023, The Authors. All rights reserved.

关键词： Chemical modification