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SSRN 2024年

作者： Lin, Wenjun Zhang, Weijie An, Zhenhua Wang, Jinhua Huang, Zuohua Zhang, Huangwei State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Department of Mechanical Engineering National University of Singapore 9 Engineering Drive 1 Singapore117576 Singapore Department of Mechanical Engineering and Science Kyoto University Kyoto daigakuKatsura Nishikyo-ku Kyoto615-8540 Japan

In this study, the effects of wall thermal conditions on the ORZ combustion modes transition in the DME/air swirl flames are investigated using the Large Eddy Simulation (LES) and Flamelet Generated Manifold (FGM) method. The results show that the ORZ chemistry and temperature are highly sensitive to the wall thermal condition. Based on the correlation between the temperature and species observed in the time-averaged numerical results, the relation between the combustion mode and temperature in the ORZ is discovered. Through temporal analysis of species and heat release rate in the ORZ, the stable Mode II and Mode IV as well as the unstable Mode III are identified. The chemical reaction pathway analysis for typical probe in the ORZ reveals that different combustion modes undergo distinct (lowtemperature or high-temperature) chemical reaction pathways. Afterwards, the definition of combustion modes used in experiments is refined by utilizing the chemical reaction data from the simulations. And it is applied to identify the combustion mode across the entire computational domain. The results confirm the consistency between the combustion modes determined in experiments based on OH and CH2O and those determined in simulations using chemical reaction rates. Finally, this explains the mechanism of the flickering flame in Mode III is the competition between the low-temperature and high-temperature reaction in the ORZ. Whereas the unstable Mode III can be stabilized by changing the wall temperature to reach the Mode II or Mode IV. © 2024, The Authors. All rights reserved.

关键词： Temperature

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

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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 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 explore the heat cascade utilization. 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. 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. 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 is carried out to obtain the optimal design performance that the net power output, thermal efficiency and exergy efficiency are 1.0.0kW, 27.5%, and 9.2% respectively. © 2023, The Authors. All rights reserved.

关键词： Geothermal heat pumps

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

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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 1.00 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

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Feasibility analysis of MA transmutation in radial fuel shuffling TWR

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Yuanzineng Kexue Jishu/Atomic Energy Science and Technology 2015年 49卷 58-62页

作者： Zheng, Mei-Yin Tian, Wen-Xi Chu, Xiao Zhang, Da-Lin Su, Guang-Hui Qiu, Sui-Zheng State Key Laboratory of Multiphase Flow in Power Engineering School of Nuclear Science and Technology Xi'an Jiaotong University Xi'an710049 China

TWR can make use of non-enriched fuel and obtain very high burnup without the need of fuel reprocessing. TWR is an effective way of fuel utilization besides the closed fuel cycle. In this paper, the feasibility of MA transmutation in a TWR was analyzed to further excavate the fuel utilization of this type of reactor. MA was homogeneously charged in the self-designed 1.250 MWt board type radial fuel shuffling sodium cooled TWR core, and the MA weight fraction is from 2.0% to 1..0%. A self-developed MCNP-ORIGEN coupled code was applied to perform burnup calculation. The results indicate that the transmutation amount increases linearly with the MA weight fraction, while the transmutation rate parabolically varies with the increase of the MA weight fraction. Neutronic safety parameters, such as the core effective multiplication factor, Doppler feedback coefficient, void worth coefficient and effective delayed neutron fraction, were compared under different MA weight fractions. The results indicate that the core effective multiplication factor and the void worth coefficient increase with the MA weight fraction, while the Doppler feedback coefficient and the effective delayed neutron fraction decrease with the increase of the MA weight fraction. © 201., Atomic Energy Press. All right reserved.

关键词： Nuclear fuel reprocessing

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Supercritical Water Gasification of Phenol with Metal Cations-A Way to Degrade Coal Industrial Wastewater and Metal-Contaminated Wastewater Simultaneously

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SSRN 2022年

作者： Cao, Wen Wang, Shaoqi Ma, Lujing Liu, Shi Jin, Hui Wei, Wenwen Guo, Liejin State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xianning West Road Xi’an710049 China Suzhou Academy of Xi’an Jiaotong University No.99 Ren’ai Road Jiangsu Suzhou215123 China

Phenol is a representative compound in coal industrial wastewater. Metal cations are the main harmful components in the wastewater of the electroplating and dyeing industries. Supercritical water gasification (SCWG) of phenol with metal cations could provide a promising way to degrade coal chemical wastewater and metal-containing wastewater simultaneously. In this study, SCWG of phenol with Mg2+, Mn2+, and Ni2+ was carried out to investigate the effect of metal cations on gasification results. Results showed that gaseous product was mainly composed of H2, CO, CH4 and CO2, and CO2 was the dominant one. Prolonging residence time and increasing the concentration of metal cations significantly increased the gas yield of CO2 and carbon gasification efficiency. Higher concentrations of metal cations facilitated methane-reforming reaction and water-gas shift reaction. Metal cations promoted the generation of 1.Ethoxybutane by the ring-breaking reaction and prevented the polymerization reaction. The order of catalytic effect was ranked as Ni2+>Mn2+>Mg2+. Mg2+, Mn2+ and Ni2+ were finally transformed into the corresponding metal hydroxides and metal oxides which could be recycled for reutilization. NiO could be reduced into metallic Ni, which consumed the H2 but effectively catalyzed SCWG of phenol. © 2022, The Authors. All rights reserved.

关键词： Phenols

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

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SSRN 2023年

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 1.0.0kW, 27.5%, and 9.2% respectively. © 2023, The Authors. All rights reserved.

关键词： Geothermal heat pumps

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Capillary Limit of a Sodium Screen-Wick Heat Pipe

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SSRN 2022年

作者： Ma, Yugao Wang, Xueqing Yu, Hongxing Huang, Shanfang Zhang, Yingnan Huang, Jian Su, Guanghui Deng, Jian Chai, Xiaoming Hu, Wenzhen School of Nuclear Science and Technology Xi’an Jiaotong University Shanxi Xi’an710049 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China Department of Engineering Physics Tsinghua University Beijing100084 China State Key Laboratory of Multiphase Flow in Power Engineering China

High-temperature alkali-metal heat pipes are passive heat transfer devices, where the capillary pressure created by the menisci in the wick pumps the condensed fluid back to the evaporator. Thus, the heat pipe heat transfer capacity is limited by the maximum capillary pressure at high heat fluxes. This work presents a two-dimensional heat and mass transfer model that includes the capillary and gravitational forces that are used to predict the capillary limit which is then validated by experimental data. The predicted critical heat flux temperature has an error of less than 20℃ and a relative error of 6%. The predicted transient sequences are consistent with the measurements. The model shows that capillary limit is affected by inclination angle, heat flux, and wick structure. For inclinations, the critical heat flux at the capillary limit is linearly related to the inclination angle with the predicted temperature rising 2 ~1.℃/s during the early stage of the capillary limit critical heat flux condition. The evaporator temperature oscillates before the capillary limit with positive inclinations. For heat fluxes, increasing the heat flux by 1.% increases the temperature increase rate 1. fold with a longer dryout length. The evaporator exhibits hysteresis after the capillary limit due to partial dryout of evaporator. For wick structures, reducing the mesh screen pitch from 80 μm to 1. μm reduces the critical heat flux to 1.% of the CHF at 80 μm. This model can accurately predict the heat pipe temperature variations at the capillary limit and can explain the physical mechanisms for the dryout oscillations and recovery hysteresis at the capillary limit. Thus, the measurements and model provide analytical guidelines for designing heat pipe cooling systems. © 2022, The Authors. All rights reserved.

关键词： Heat flux

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Oxidation of Typical Zr-1.b Alloy in High-Temperature Air Under 700–900 °C

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SSRN 2022年

作者： Jiang, Guanyu Xu, Donghai Liu, Lu Ding, Xin Kuang, Wenjun Wang, Mingjun Key Laboratory of Thermo-Fluid Science & Engineering Ministry of Education School of Energy and Power Engineering Xi’an Jiaotong University Shaanxi Province Xi’an710049 China School of Materials Science and Engineering Xi’an Jiaotong University Shaanxi Province Xi’an710049 China State Key Laboratory of Multiphase Flow in Power Engineering Department of Nuclear Science and Technology Xi'an Jiaotong University Xi’an China

m-ZrO2 is always the dominant phase, while oxide shapes, the integrity and roughness of oxide films share evident differences. At 900 &#1.6;C, M5 alloy exhibits kinetics transition and breakaway oxidation at approxima... 详细信息

m-ZrO2 is always the dominant phase, while oxide shapes, the integrity and roughness of oxide films share evident differences. At 900 °C, M5 alloy exhibits kinetics transition and breakaway oxidation at approximately 80 min. The pre-transition oxidation follows a parabola kinetics with the rate exponent n being 1.65. The presence of ZrO and ZrO0.35 sub-oxides accounts for the high reaction activation energy (1.9.6 kJ/mol). During the kinetics transition, some intergranular cracks turn transgranular, and pores distribute on the oxide layer and O/M interface. Air ingress through the oxide layer is jointly affected by air transport and ion diffusion. © 2022, The Authors. All rights reserved.

关键词： Oxidation

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PREFACE: SPECIAL ISSUE FOR THE 2ND INTERNATIONAL SYMPOSIUM ON THERMAL-FLUID DYNAMICS (ISTFD2021.

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Heat Transfer Research 2022年第8期53卷 V-VI页

作者： Cheng, Lixin Bai, Bofeng Guo, Zhixiong School of Energy and Power Engineering Beijing University of Technology Beijing100124 China Department of Engineering and Mathematics Sheffield Hallam University SheffieldS1 1WB United Kingdom State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Department of Mechanical and Aerospace Engineering Rutgers The State University of New Jersey PiscatawayNJ08854 United States

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Numerical Study of High-Energy Spark Ignition Characteristics in a Scramjet Combustor

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SSRN 2024年

作者： Gao, Ziyan Zhang, Meng Zhang, Zhibo Wu, Yun Zheng, Xing Miao, Huifeng National Key Lab of Aerospace Power System and Plasma Technology Xi’an Jiaotong University Xi’an710049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong Universiy Xi’an710049 China National Key Lab of Aerospace Power System and Plasma Technology Air Force Engineering University Xi’an710038 China Shaanxi Key Laboratory of Environment and Control for Flight Vehicle School of Aerospace Engineering Xi’an Jiaotong University Shaanxi 710049 China

Reliable ignition is a fundamental prerequisite for the scramjet engines. In order to improve the reliability of ignition, further enhance the application of spark ignition in engineering, and improve the ignition ability in the field of supersonic combustion, an innovative long electrode distance high-energy spark igniter (LHSI) system was proposed by our research team. To reveal the instantaneous ignition characteristics of the LHSI, a simulation model of the LHSI is established and verified by experiments. Based on this, the formation and development of the initial fire core of vaporized kerosene and the ignition characteristics of LHSI in a scramjet combustor were simulated and compared with the conventional high-energy spark igniter (HSI). The analysis revealed that the success of the cavity ignition is greatly influenced by the local equivalent ratio of the initial {1. field and the penetration depth of the initial flame core. Meanwhile, the fore recirculation zone of the cavity plays a key role in stabilization and development of the initial fire core. Compared with the HSI, the LHSI can produce initial flame core with higher penetration and greater size, which is the main reason for why LHSI has a broader ignition boundary. © 2024, The Authors. All rights reserved.

关键词： Ignition

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