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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

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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

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

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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

Effect of heavy metal ions on the hydrogen production performance of Rhodobactersphaeroides HY01

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Effect of heavy metal ions on the hydrogen production perfor...

第十五届全国氢能会议暨第7届两岸三地氢能研讨会

作者： Honghui Yang Hongyu Ma Lingdi Li Hao Xu Wei Yan State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049P.R.China Department of Environmental Science & Engineering Xi'an Jiaotong UniversityXi'an 710049P.R.China

A newly isolated photosynthetic bacterium,Rhodobactersphaeroides HY01 showed high hydrogen production performance(*** Energy39,10051-60)and good flexibility on genetic modification(*** Energy 39,14633-41).In order to investigate its potential on using wastewater containing heavy metal ions for photosynthetic hydrogen production,four conventional heavy metal ions,Pb2+,Cu2+,Cr6+ and Cd2+ were studied for their effects on the photosynthetic hydrogen production performance of Rhodobactersphaeroides HY01.

关键词： photosynthetic hydrogen production heavy metal ions Rhodobactersphaeroides HY01

An Operation Optimization of Cooling System for Reactor Shutdown in Pebble Bed Gas-Cooled Reactor

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SSRN 2024年

作者： Liu, Junfeng Wang, Chenglong Qiu, Suizheng Wang, Boyuan Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology Shaanxi Engineering Research Center of Advanced Nuclear Energy Xi’an Jiaotong University Xi’an710049 China Xi’an Thermal Power Research Institute Co. Ltd Xi’an710049 China State Key Laboratory of Multiphase Flow in Power Engineering China

For the emergency shutdown of a high temperature gas-cooled reactor pebble-bed module (HTR-PM) in its operation conditions, in the current design method with a low-flow auxiliary steam cooling technical solution, there are some security and economic issues, i.e. high thermal shock, long cooling time, and temperature drop rate exceeding the limit. To solve these problems, an optimized design method for the shutdown cooling system is presented. Through a simulation model of the shutdown cooling system based on Matlab/Simulink, the dynamic characteristics of the shutdown cooling system in its operation conditions are obtained, involving shutdown, low flow cooling, and water supply start-up stages. The results showed that with the optimized design method, the safety of the core and steam generator can both be ensured during the cooling process, and the cooling rate is significantly improved. Therefore, the optimized design method is feasible and advanced. © 2024, The Authors. All rights reserved.

关键词： Cooling

Experimental Study on Stable Jet Impact Process Under Simulated Pipeline Rupture

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Experimental Study on Stable Jet Impact Process Under Simula...

Student Conference on Research and Development (SCOReD)

作者： Zhang Tao Bi Qincheng Zhao Jinle Wang Teng Chen Jingrong Feng Fan State Key Lab Multiphase Flow Power Engn Xi’an Jiaotong University Xi’an Shaanxi China School of Energy Power and Mechanical Engineering North China Electric Power University Bao’ding Hebei China

ISBN: (数字)9798350318821

ISBN: (纸本)9798350318838

In this study, an advanced experimental system was utilized that incorporated heating, jetting, recycling, and cooling capabilities to ensure the successful execution of stable jet impact experiment that simulating a pipeline complete rupture. High-temperature resistant tempered glass was employed in the experimental system to realize the visibility. During the experiment, 8mm pipes/nozzles of varying lengths were employed as the test sections, and jetting phenomena when the import status is single-phase cold water or two-phase mixture at 0-2MPa were obtained by high-resolution photos. Additionally, the shape of the jet cone and the impact force exerted on the target plate were meticulously analyzed after the working fluid under different state parameters jetting into an atmospheric pressure environment through pipes/nozzles. The research also focused on the variation trend in the magnitude of the jet-impact force, as a function of inlet pressure and temperature, target plate distances, and length-to-diameter ratios. The research findings revealed that cold water(below 100°C), sub-cooled water(above 100°C but not reaching saturation temperature), and two-phase steam-water mixture exhibited distinct jet cone shapes during the jetting process, resulting in varying distributions of the jet force. Furthermore, the distance from the spout to the target plate and the length-to-diameter ratio significantly influenced the magnitude of the jet impact force.

关键词： Resistance Visualization Temperature distribution Fluids Shape Force Pipelines

Radiation transmission simulation for volumetric solar receiver by Monte Carlo method

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Huagong Xuebao/CIESC Journal 2011年第SUPPL. 1期62卷 60-65页

作者： Cui, Fuqing He, Yaling Cheng, Zedong Li, Dong Tao, Yubing State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Xi'an 710049 Shaanxi China

The optical model of the volumetric solar receiver has been built and corresponding solar radiation propagation process within the receiver is simulated by the Monte Carlo ray tracing method(MCRT). In the computation, the complicated photon transmission process in the SiC porous absorber is simplified as the transmission process in the statistically homogeneous and isotropic turbid media. Meanwhile, the non-uniform cylindrical coordinate grid is applied in the statistics of the absorbing energy distributions, which could reduce much computation effort compared with normal uniform grid. Based on the above model, the energy distribution of irregular macro scale porous absorber is counted. The results show that, under the given working condition, the radiation heat flux is concentrated at the top area of absorber and the maximum heat flux value is up to 2.87 × 109 W· m-3, but it decreases quickly in the sideward area. The heat flux distribution of whole porous absorber exhibits a great non-uniform characteristic, which would affect the stability and safety of receiver. © All Rights Reserved.

关键词： Monte Carlo methods

Investigation of the Solar-Driven Chemical Looping Methane Dry Reforming on Rh-Doped LaCeO3.5 Oxygen Carrier

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SSRN 2024年

作者： Li, Peng Gai, Zhongrui Zhang, Jinrui Rao, Qiong Tang, Sanli Shen, Yuanhui 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

The feasibility of a solar-driven chemical looping dry reforming of methane (DRM) process, which converts solar energy and methane into syngas via a looping material oxygen carrier is investigated experimentally. Thermogravimetric analysis (TGA) experiments were firstly carried out to verify the effect of the Rh-doped LaCeO3.5 which were synthesized via modified Pechini method and incipient wetness method and the result shows that Rh greatly improved the reaction kinetics. Photo-TGA experiments were conducted to evaluate the light effect in chemical looping DRM. Under the light condition, the Rh-doped LaCeO3.5 shows higher methane conversion, oxygen extraction rate and CO selectivity compared with the undoped one, decreasing the apparent activation energy of the reaction at the same time. Insights obtained from the UV-Vis spectroscopy verified that the surface Rh under the light could promote the activation of surface methane species and increase the light absorbance. Meanwhile, the FEM methods were used to obtain the distributions of the temperature fields of the photo-TGA reactor through the calculation of the coupling of the fluid, reaction and temperature fields. In this way, the conversion mechanism of the solar, heating and chemical energy was illustrated and furthermore, the calculated surface reaction rate and the variation tendency of the outlet-gas were consistent with the experimental results. Through the integration of solar energy, a high methane to solar fuel conversion efficiency could be achieved. The proposed process has the potential to produce solar fuels at high efficiency with reduced carbon footprint. © 2024, The Authors. All rights reserved.

关键词： Methane

Research on the Combustion Effect and Mechanism of Aluminum Droplets in Ap/Htpb Composite Propellant

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SSRN 2023年

作者： Yang, Bin Wang, Jiahao Lou, Yongchun Zhao, Yu Wang, Ji Wang, Ying 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 Shanghai Space Propulsion Technology Research Institute Shanghai201109 China

To investigate the combustion phenomenon of aluminum droplets within propellants, this study amalgamates the evaporation combustion process of aluminum droplets with the AP/HTPB (Ammonium perchlorate/Hydroxyl-terminated polybutadiene) multi-flame structure model. Consequently, a numerical simulation approach is established to depict the combustion behavior of aluminum droplets in a high-temperature gas environment. The paper scrutinizes the dynamics, deformations, combustion characteristics, and their influence on the propellant flow field under diverse conditions. The findings of this research affirm that the non-uniform flow velocity at the AP and HTPB inlets imparts distinct pressures on the droplets' surface, thereby precluding their spherical morphology. As the droplet diameter diminishes, the effect of deformation gradually abates, leading the droplets to gravitate towards the AP region. The addition of aluminum droplets disrupts and enhances heat transfer within the external flow field of propellant combustion, while their own combustion engenders a substantial amount of heat, thus elevating the overall combustion temperature of the propellant. Moreover, aluminum droplets perturb the distribution of different components in the flow field, affording more opportunities for intermolecular encounters, and consequently augmenting the efficiency of the overall reaction compared to scenarios without aluminum droplets. Remarkably, the combustion efficiency of aluminum droplets is amplified in high-pressure environments. © 2023, The Authors. All rights reserved.

关键词： flow fields

Photocatalytic desulfurization of gasoline by TiO2 coupling with ultrasonic

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Ranliao Huaxue Xuebao/Journal of Fuel Chemistry and Technology 2010年第4期38卷 428-433页

作者： Chen, Song-Xuan Zhao, Jing-Lian Su, Ci State Key Laboratory of Multiphase Flow in Power Engineering Department of Environmental Engineering Xi'an Jiaotong University Xi'an 710049 China

The photocatalytic oxidation of dibenzothiophen (DBT) in octance (as solvent) was conducted using O2 in air as the oxidant, TiO2 prepared by sol-gelatin method as the photocatalyst and coupling with ultrasonic. The effect of light distance, photocatalyst amount, reaction time, DBT initial concentration and ultasonic power on the removal of DBT were investigated deeply. The results show that the degradation rate of DBT increases by 10% by using ultrasonic. Under the conditions of TiO2 dosage of 2 g/L, air flow rate of 800 mL/min, distance of UV light of 20 cm, initial concentration of DBT of 600 mg/L, reaction time of 150 min, ultrasound power of 500 W, the degradation rate of DBT can reach up to 72.6%.

关键词： Ultrasonics