检索结果-内蒙古大学图书馆

Effect of 2,5-dimethylfuran addition on ignition delay times of n-heptane at high temperatures

学校读者我要写书评

暂无评论

Frontiers in Energy 2019年第3期13卷 464-473页

作者： Zhenhua GAO Erjiang HU Zhaohua XU Geyuan YIN Zuohua HUANG State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China

The shock tube autoignition of 2,5-dimethylfuran (DMF)/n-heptane blends (DMF)/n-100%, by mole fraction) with equivalence ratios of 0.5, 1.0, and 2.0 over the temperature range of 1200-1800 K and pressures of 2.0 atm and 10.0 atm were investigated. A detailed blend chemical kinetic model resulting from the merging of validated kinetic models for the components of the fuel blends was developed. The experimental observations indicate that the ignition delay times nonlinearly increase with an increase in the DMF addition level. Chemical kinetic analysis including radical pool analysis and flux analysis were conducted to explain the DMF addition effects. The kinetic analysis shows that at lower DMF blending levels, the two fuels have negligible impacts on the consumption pathways of each *** the DMF addition increases to relatively higher levels, the consumption path of n-heptane is significantly changed due to the competition of small radicals, which primarily leads to the nonlinear increase in the ignition delay times of DMF/n-heptane blends.

关键词： ignition delay time shock tube kinetic model 2,5-dimethylfuran (DMF) n-heptane

Aeroderivative Gas Turbine and Composite Sco2 power Cycle Integrated System: Towards Large-Scale Gas-to-power Efficient Conversion

学校读者我要写书评

暂无评论

SSRN 2023年

作者： Jiang, Yuemao Wang, Shunsen Su, Wen Li, Bo Wang, Zhe State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an710049 China School of Energy Science and Engineering Central South University Changsha410083 China National Center for International Research of Subsea Engineering Technology and Equipment Dalian Maritime University Dalian116026 China

power-to-Gas is proving to be an effective means of storing electricity from renewables on a large scale. Nevertheless, there is yet to be a clear technical route for large-scale hydrogen-enriched gas conversion into electricity (Gas-to-power). This paper proposed a novel integrated power system consisting of an aeroderivative gas turbine and a composite supercritical CO2 (sCO2) power cycle. In addition, a new evaluation indicator based on exergy was also proposed to reveal the real waste heat recovery capacity and select the sCO2 cycles. After that, a comprehensive energy, exergy, exergoeconomic, and environment (4E) analysis and global parametric studies were conducted for the integrated system. Finally, an entropy-based TOPSIS decision-maker was combined with the tri-objective optimization algorithm for the combined cycle integrated design. Thermodynamic optimization results show that, unlike the thermal efficiency, the exergy efficiency of the partial heating sCO2 cycle of 48.3% is higher than that of the recuperated one. With the exhaust gas carrying 21% of fuel exergy, the total exergy recovery efficiency is 51.7%, and the fuel efficiency of the integrated system is over 50%. As for the exergoeconomic, the combustor alone is responsible for 77.1% of the total exergy destruction, the initial cost of the bottoming cycle is less than half that of the gas turbine, and the high-pressure turbine has the highest exergoeconomic factor of 91.5%. The key parameters of the gas turbine significantly influence the performance of the sCO2 cycle and the integrated system 4E performance. There is an optimal gas turbine inlet temperature of about 1500 K to minimize the LCOE. After the multi-objective integrated optimization, the overall efficiency, LCOE, and specific gas emissions are 50.2%, 7.8 cents/kWh, and 396.8 g/kWh, respectively, which are all higher than those from optimizing the bottoming cycle alone. It is considered that the technical solutions and research results

关键词： Gas turbines

Curvature Adaptive Voxel-Based Monte Carlo Method with Application for Customized Retinal Laser Surgery

学校读者我要写书评

暂无评论

SSRN 2024年

作者： Zhang, Hao Li, Dong Chen, Bin Zhang, Hanfeng Liang, Yao Zheng, Yuping Wang, Guoxiang State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Department of Ophthalmology 2nd affiliated hospital Medical School Xi’an Jiaotong University Xi’an710049 China Department of Mechanical Engineering The University of Akron AkronOH44325 United States

Accurate prediction of light propagation and energy deposition in biological tissues is crucial for the success of laser-based medical treatments. We propose a novel Curvature Adaptive Voxel-based Monte Carlo method (CAVMC) to correct for light reflection and refraction at curved interfaces by introducing coordinate transformation with an artificial surface parallel to the curved interface. This approach achieves an optimal balance between simulation accuracy and efficiency. Our study demonstrates that for small optical mismatches, the relative error can be reduced significantly, with the energy deposition error dropping from 34.7% to 6.6%. For large optical mismatches, CAVMC substantially improves accuracy, reducing computational errors by more than 50%. We validated CAVMC in a customized retinal laser therapy scenario for diabetic retinopathy, demonstrating its ability to accurately predict laser energy deposition and thermal effects, which is crucial for avoiding tissue damage during treatments. The efficiency and accuracy of the CAVMC method make it valuable for personalized retinal laser surgery and potentially other medical applications. Overall, CAVMC offers a robust tool for simulating light propagation in heterogeneous biological tissues, enhancing the precision and safety of medical treatments. © 2024, The Authors. All rights reserved.

关键词： Laser surgery

Thermodynamic Analysis of a Hybrid Energy System Coupling Solar Organic Rankine Cycle and Ground Source Heat Pump: Exploring Heat Cascade Utilization

学校读者我要写书评

暂无评论

SSRN 2023年

作者： Chen, Liangqi Yue, Huifeng Wang, Jiangfeng Lou, Juwei Wang, Shunsen Guo, Yumin Deng, Bohao Sun, Lu State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an710049 China China United Northwest Institute for Engineering Design & Research Co. Ltd Xi’an710077 China School of Human Settlements and Civil Engineering Xi'an Jiaotong University Xi’an710049 China

The demand for efficient utilization of renewable energy is growing and the hybrid energy system driven by solar and geothermal energy is a significant way to minimize carbon emission and achieve carbon neutrality. This paper presents a hybrid energy system coupling solar organic Rankine cycle (S-ORC) with ground source heat pump (GSHP) for heating and power supply to further increase thermal efficiency and explore the heat cascade utilization of hybrid energy system during the heating season. In the hybrid energy system, the ground heat exchanger (GHE) is shared by the S-ORC and GSHP systems and the waste heat from the condenser of S-ORC is recovered to enhance the coefficient of performance (COP) of GSHP. A mathematical model is optimized to analyze the parametric effects on thermodynamic performance under different operating conditions. The comparison between the hybrid energy system and the stand-alone GSHP system is performed to present the superiority of energy recycling. The results indicate that the COP of the hybrid energy system can be improved up to 6.5 which shows the obvious advantage compared to 2.8 of the stand-alone GSHP system under the given system conditions. In addition, the increase of turbine inlet pressure can not only reduce the area of solar fields and length of buried tubes, but also contribute to the thermodynamic performance of the hybrid energy system. Furthermore, the hybrid energy system can obtain optimum exergy efficiency by matching ground source temperature and condensation temperature in the ORC unit. For a building of 3000m2 with heating and power supply, multi-objective optimization by means of a genetic algorithm is carried out to obtain the optimal design performance that the net power output, thermal efficiency and exergy efficiency are 180.0kW, 27.5%, and 9.2% respectively. © 2023, The Authors. All rights reserved.

关键词： Geothermal heat pumps

Comparative Analysis on Energy Losses in Hydrogen and Helium Turbo-Expanders for Hydrogen Liquefiers

学校读者我要写书评

暂无评论

SSRN 2022年

作者： Zhou, Kaimiao Chen, Liang Li, Shanfeng Zhao, Kang Zhang, Ze Chen, Shuangtao Hou, Yu State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Beijing institute of Aerospace Testing Technology Beijing100074 China

The helium Brayton cycle and the hydrogen Claude cycle are the baseline processes for large-scale hydrogen liquefaction. Helium and hydrogen turbo-expanders are the crucial components, respectively, determining the system efficiency and reliability. In this paper, a comparative analysis is performed on the energy losses in helium and hydrogen turbo-expanders for hydrogen liquefaction systems. Similarity analysis is carried out to set the baseline design of helium and hydrogen turbo-expanders. Mean-line method is employed in the design, and losses in nozzle and impeller are determined. CFD simulations are performed to illustrate the internal flow field and loss mechanisms in helium and hydrogen turbo-expanders. The CFD predictions of isotropic efficiency agree well with that by the loss models. The results show that the passage loss in the impeller is the dominant loss for cryogenic hydrogen and helium turbo-expanders. Due to the higher sound speed and lower viscosity, the hydrogen turbo-expander has smaller nozzle loss and incidence loss compared with the helium turbo-expander, but the tip clearance loss and residual velocity loss in the hydrogen expander are larger. © 2022, The Authors. All rights reserved.

关键词： Helium

Propagation and Burning Velocity of Iron-Methane-Oxygen-Nitrogen Turbulent Expanding Flames

学校读者我要写书评

暂无评论

SSRN 2023年

作者： Cai, Xiao Su, Limin Su, Shouguo Wang, Jinhua Alden, Marcus Li, Zhongshan Huang, Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Division of Combustion Physics Lund University P.O. Box 118 LundS221 00 Sweden

The propagation and burning velocity of iron-methane-oxygen-nitrogen turbulent expanding flames were experimentally studied by employing a newly optimized spark-ignition, fan-stirred combustion chamber, in which micron-sized iron particles can be dispersed homogeneously. Fine iron particles with averaged diameter of 1.9 μm was used in the present study. The flame trajectory of iron-methane mixture at different turbulence intensities and iron concentrations was recorded using a high-speed camera. It was found that the flame propagation speed increases as iron-methane turbulent flame expands. The acceleration process is mainly caused by the extension of flame surface dissipation spectrum by increasing the largest flame scales (flame radius). The turbulent burning velocity, ST increases significantly with the turbulence intensity, which is well known feature in gaseous flames. However, the iron concentration does not have an obvious effect on the ST, which is unique to iron flame in turbulence environment. Because the turbulent flame propagation is dominated by turbulent heat transfer, which is characterized by turbulence intensity. In addition, the formation of iron flame front is controlled by the couple effects of iron concentration and turbulence intensity in turbulent environment. Furthermore, the laminar burning velocity, SL was accurately determined using a nonlinear extraction method. A correlation of turbulent burning velocity was obtained based on the experimental iron-methane data. The measured ST and its correlation would be used to develop practical iron burners and to validate turbulent combustion models of iron flames. © 2023, The Authors. All rights reserved.

关键词： Iron

Waste Tire-Derived Graphene Modified Carbon as Anodes for Sodium-Ion Batteries

学校读者我要写书评

暂无评论

SSRN 2024年

作者： Zhou, Ziyi Wang, Silang Wen, Bo Xiao, Jiyuan Yang, Guorui Ding, Shujiang School of Chemistry Engineering Research Center of Energy Storage Materials and Devices Ministry of Education "Four Joint Subjects One Union" School Enterprise Joint Research Center for Power Battery Recycling & Circulation Utilization Technology Xi’an Jiaotong University Xi’an710049 China Xi’an Key Laboratory of Solid Waste Recycling and Resource Recovery State Key Laboratory of Multiphase Flow in Power Engineering Department of Environmental Science and Engineering Xi’an Jiaotong University Xi’an710049 China

The rational disposal of waste tires poses a ubiquitous challenge globally. Pyrolytic carbon black, a solid by-product produced through pyrolysis, has great application prospects. Carbon-based materials are regard as the most potential commercial anode materials for sodium-ion batteries (SIBs) ， which features cheap, environmentally friendly, and low reaction potential. In this study, three-dimensional vertical graphene composite (TCBp@VGSs) was synthesized from waste tires. The graphene with higher defectiveness offers an increased number of active sites for Na+, while the vertically aligned graphene facilitates rapid electron transfer. As a result, the TCBp@VGSs electrode demonstrates the ability to maintain a reversible capacity of 252.7 mA h g-1 after 100 cycles at a current density of 0.2 A g-1. Furthermore, it exhibits a sustained rate performance of 105.4 mA h g-1 at a current density of 5 A g-1. Moreover, even after 1900 cycles at a current density of 1 A g-1, a reversible capacity of 171.5 mA h g-1 is retained, showcasing good stability and a significantly higher capacity compared to TCBp-1100. This study introduces novel approaches for the high-value utilization of solid-phase by-products from waste tires, offering certain economic benefits, and contributes fresh insights into the advancement of SIBs anodes. © 2024, The Authors. All rights reserved.

关键词： Graphene

Optimization of dynamic compressed CO2 energy storage system: The role of supercritical fluid properties

学校读者我要写书评

暂无评论

Energy 2025年 328卷

作者： Guo, Yuandong Xu, Jinliang Yu, Xiongjiang Sun, Enhui Xie, Jian Liu, Guanglin Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization North China Electric Power University Beijing100026 China Beijing Huairou Laboratory Beijing101400 China Ministry of Education Beijing102206 China

The rising demand for efficient energy storage has spurred the development of technologies like liquefied CO2 energy storage systems, which reduce pressure fluctuations by storing CO2 as a liquid. Traditionally, the storage temperature of CO2 is the saturation liquid temperature because evaporation compensation helps maintain stable pressure during gas release. However, the liquefied CO2 energy storage system suffers low round-trip efficiency due to low temperature for liquefaction. Here, we propose a compressed CO2 energy storage (CCES) system using the properties of supercritical fluids to extend the discharging time. The core optimization strategy involves storing sCO2 near the pseudo-critical temperature during the charging process, which facilitates more efficient expansion of sCO2 during the discharging process, thereby extending the discharging time. Then, a dynamic CCES system incorporating three-stage compression and three-stage expansion are proposed. With the compression power consumption of 100 MW, the high-pressure tank is set to be 14.00 MPa and 7.50 MPa before and after discharging. Based on the discharging optimization method, the round-trip efficiency improves from 66.50 % to 69.32 %, and the discharging time extends from 0.96 h to 3 h. Our work fills the gap in the selection criteria for storage parameters of CCES system, and significantly improving the performance of CCES system. © 2025

关键词： Supercritical fluids

A Dynamic Plunger Lift Model for Shale Gas Wells

学校读者我要写书评

暂无评论

Fluid Dynamics & Materials Processing 2023年第7期19卷 1735-1751页

作者： Shiyu Miao Xiao Liu Xiaoya Feng Haowen Shi Wei Luo Peng Liu Petroleum Engineering Institute of Yangtze University Wuhan430100China Laboratory of Multiphase Pipe Flow Gas Lift Innovation CenterChina National Petroleum Corp.Yangtze UniversityWuhan430100China Key Laboratory of Drilling and Production Engineering for Oil and Gas Wuhan430100China Sichuan Shale Gas Exploration and Development Limited Liability Company Chengdu640000China Sichuan Changning Gas Development Company PetroChina Southwest Oil&Gas Field CompanyChengdu610051China Oil and Gas Technology Research Institute of Changqing Oilfield Company PetroChinaXi’an710018China

At present,the optimization of the plunger mechanism is shale gas wells is mostly based on empirical methods,which lack a relevant rationale and often are not able to deal with the quick variations experienced by the production parameters of shale gas wells in comparison to conventional gas *** order to mitigate this issue,in the present work,a model is proposed to loosely couple the dynamics of gas inflow into shale gas wells with the dynamics of the liquid *** from the flow law that accounts for the four stages of movement of the plunger,a dynamic model of the plunger lift based on the real wellbore trajectory is *** model is then tested against 5 example wells,and it is shown that the accuracy level is higher than 90%.The well‘switch’,optimized on the basis of simulations based on such a model,is tested through on-site *** is shown that,compared with the original switch configuration,the average production of the sample well can be increased by about 15%.

关键词： Shale gas well complex and more complex well bore structure plunger lift loose coupling simulation model