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Performance Analysis of Low GWP Refrigerants R1234yf and R448A in a Small High and Low-temperature Test Equipment

Recent Patents on Mechanical engineering 2022年第3期15卷 277-284页

作者： Liqiang, Zhou Zhang, Hua Zilong, Wang Wenjing, Gao School of Energy and Power University of Shanghai for Science and Technology Shanghai200093 China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering Shanghai200093 China

Aim: The article presents an analysis of the feasibility of R1234yf and R448A, two new low GWP refrigerants, as alternatives to R404A in the refrigeration system of small high and low-temperature test equipment. Methods: The physical properties of R448A and R404A are similar. Compared with R404A, the GWP of R1234yf and R448A reduced by 99.9% and 67.7%, respectively. The analysis is based on an experimental comparison of R404A with R448A and R1234yf, comparing the compressor discharge tempera-ture, COP, cooling capacity, and the cooling rate of three refrigeration systems at different ambient temperatures. Results: The experimental results show that the cooling capacity of R448A is better than R404A at a higher condensing temperature. Conclusion: When the charging volume is 230g, and the ambient temperature is 25°C, the COP of the R448A system is increased by about 24.63% compared with the R404A system. © 2022 Bentham Science Publishers.

关键词： Refrigerants

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Study on startup characteristics of prototype once-through steam generator for China fast reactor

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International Journal of Advanced Nuclear Reactor Design and Technology 2022年第1期4卷 26-35页

作者： Min, Xin Zhang, Dalin Xu, Rongshuan Wang, Shibao Chen, Youchun Wang, Chenglong Tian, Wenxi Qiu, Suizheng Su, G.H. State Key Laboratory of Multiphase Flow in Power Engineering Shaanxi Key Lab. of Advanced Nuclear Energy and Technology School of Nuclear Science and Technology Xi'an Jiaotong University Xi'an710049 China

Once-through steam generator (OTSG) is a vital heat transfer equipment of China Fast Reactor-600 (CFR-600), and its startup characteristics are of great importance to the safe operation of nuclear power plant. In this paper, first of all, the Thermal-hydraulic analysis Code Of Sodium heated once-through Steam generator (TCOSS) has been further optimized, and the code was introduced in the text. Secondly, the Steam Generator Test Facility (SGTF) and India Commercial Fast Breeder Reactor (CFBR) were selected for steady-state verification, and the feedwater flow rate increase condition of the prototype OTSG experiment was selected for transient verification. All the verifications were in good compliance, which proved the reliability of the TCOSS code for subsequent calculation of startup conditions. Finally, taking the prototype OTSG of CFR-600 as the research object, and the transient characteristics of cold startup and hot startup have been predicted and analyzed. The results show that both processes of cold startup and hot startup for prototype OTSG can be realized stably. The simulation results of startup processes showed a good agreement with expectations, which can provide support for the development of CFR-600 steam generator. © 2022 Xi'an Jiaotong University

关键词： Steam generators

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A Simulation Study of Solar Thermal Steam Generation for Thermal Recovery of Thick Oil Based on Aspen Plus 4

A Simulation Study of Solar Thermal Steam Generation for The...

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2022 4th International Conference on New Energy System and Electrical engineering, NESEE 2022

作者： Chen, Pengfei Chen, Kang Peng, Huaiwu Zhang, Yanlong Bawaa, Baercheng Zhao, Qiuyang Institute of Solar Engineering Technology Northwest Engineering Corporation Limited PowerChina Xi'an China State Key Laboratory of Multiphase Flow in Power Engineering Xi'An Jiaotong University Xi'an710049 China

High-temperature steam injection is a common means of thermal recovery of thick oil. Although the steam injection boiler currently used for thick oil injection can achieve fast start-stop control, the power consumption of the pump is large, and the boiler control is demanding. Besides, a large amount of fossil fuel is needed to supply the heat required for steam heating. Using solar thermal to realize the transformation of solar energy-molten salt heat energy-steam energy can effectively reduce the burning of fossil fuels and realize clean thermal recovery of thick oil. To ensure the actual demand of thermal recovery of thick oil, it is necessary to determine a reasonable steam evaporation volume and vapor phase fraction. This paper simulates a solar thermal heat exchange system for molten salt-steam based on Aspen Plus. The simulation results show that the heat load and required solar panel area of all heat exchangers rise when the evaporation volume increases. However, the superheater grows most slowly. When the vapor phase fraction at the evaporator outlet rises to 1, there is no phase change heat transfer in the superheater, and its heat load plummets to 230 kW. © Published under licence by IOP Publishing Ltd.

关键词： Steam

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Numerical Simulation Study on Wet Gas flowmetering Overreading Characteristics of Venturi Tube under Low Pressure Conditions 3

Numerical Simulation Study on Wet Gas Flowmetering Overreadi...

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3rd International Conference on Testing Technology and Automation engineering, TTAE 2023

作者： Xing, Zhaokai Wu, Fang Hu, Rongyuan Xu, Guobin Xie, Hongjun Fan, Shaohua Wang, Shanshan Yang, Jinfeng Meng, Lin Liu, Qihang State Nuclear Electric Power Planning Design & Research Institute Co Ltd Beijing100095 China Shandong Nuclear Power Company Ltd Yantai265116 China Xi'an Jiaotong University State Key Laboratory of Multiphase Flow in Power Engineering Xi'an710049 China

ISBN: (纸本)9781510674769

A numerical simulation study of Venturi overreading characteristics is carried out with Mixture model and Realizable k-e model, and a prediction model of Venturi overreading under low pressure conditions is proposed. Compared with the existing experimental data, it demonstrates that the numerical simulation results have high accuracy, the results indicate that the quality is the main factor affecting the Venturi overreading Meanwhile, the model in this paper is compared with with ten classical overreading prediction models such as homogeneous model. It shows that the average prediction deviation of the model in this paper is 3.2%, ranking second, and the maximum prediction deviation is 7.3%. This study can provide reference for the study of Venturi wet gas flowmetering overreading model, and also provide a theoretical basis and options for flowmetering technology. © 2024 SPIE.

关键词： Forecasting

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Experimental and Numerical Investigations on Heat Transfer Characteristics of Supercritical Water in a Vertical Tube

SSRN

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SSRN 2024年

作者： Du, Xiaocheng An, Ning Wei, Ziyu Yang, Dong State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University China

Heat transfer performance of working medium is important for supercritical units. In this work, heat transfer experiments and simulations were carried out at 25 to 29.8 MPa. The impacts and influence mechanisms of operation parameters on heat transfer characteristics were analyzed. To describe the fluid heat storage capacity, a metric called cdv is proposed. The findings indicate that thermal conductivity, cdv, and flow turbulence intensity are the three types of factors influencing heat transfer characteristics. As mass flux rises, the radial flow turbulence intensity increases, leading to an improvement in heat transfer performance. The impact of heat flux is mainly showed in high enthalpy zone. Due to the reduction in radial thermal conductivity, heat transfer enhances as heat flux decreases. Large specific heat zone, where the thermophysical parameters vary quickly, are where the influence of pressure is most evident. Because of the high thermal conductivity and cdv, the heat transfer characteristics get better as pressure drops. Finally, typical heat transfer correlations were evaluated using experiment results. The Bishop, Mokry and Miropoiskii-Shitsman correlations exhibited relatively large errors, and the correlations proposed by Swenson and Jackson have a low error and are highly consistent with the experiment results. © 2024, The Authors. All rights reserved.

关键词： Heat flux

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Life Cycle Assessment Analysis and Comparison of 1000 MW S-CO_(2)Coal Fired power Plant and 1000 MW USC Water-Steam Coal-Fired power Plant

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Journal of Thermal Science 2022年第2期31卷 463-484页

作者： LI Mingjia WANG Ge XU Jinliang NI Jingwei SUN Enhui Key Laboratory of Thermo-Fluid Science and Engineering of Ministry of Education School of Energy&Power EngineeringXi’an Jiaotong UniversityXi’an 710049China Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization North China Electric Power UniversityBeijing 102206China

The objective of this paper is to understand the benefits that one can achieve for large-scale supercritical CO_(2)(S-CO_(2))coal-fired power *** aspects of energy environment and economy of 1000 MW S-CO_(2)coal-fired power generation system and 1000 MW ultra-supercritical(USC)water-steam Rankine cycle coal-fired power generation system are analyzed and compared at the similar main vapor parameters,by adopting the neural network genetic algorithm and life cycle assessment(LCA)***-objective optimization of the 1000 MW S-CO_(2)coal-fired power generation system is further carried *** power generation efficiency,environmental impact load,and investment recovery period are adopted as the objective *** main vapor parameters of temperature and pressure are set as the decision *** results are concluded as ***,the total energy consumption of the S-CO_(2)coal-fired power generation system is 10.48 MJ/k Wh and the energy payback ratio is 34.37%.The performance is superior to the USC coal-fired power generation ***,the resource depletion index of the S-CO_(2)coal-fired power generation system is 4.38μPRchina,90,which is lower than that of the USC coal-fired power generation system,and the resource consumption is ***,the environmental impact load of the S-CO_(2)coal-fired power generation system is 0.742 m PEchina,90,which is less than that of the USC coal-fired power generation system,0.783 m PEchina,*** all environmental impact types,human toxicity potential HTP and global warming potential GWP account for the most environmental ***,the investment cost of the S-CO_(2)coal-fired power generation system is generally less than that of the USC coal-fired power generation system because the cost of the S-CO_(2)turbine is only half of the cost of the steam *** optimal turbine inlet temperature T_(5)becomes smaller,and the optimal turbine inlet pressure is unchanged at 622.082°C/30 MPa.

关键词： S-CO_(2)power plant ultra-supercritical water-steam Rankine cycle power plant life cycle assessment energy efficiency environment impact economic performance

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Evaporation and drying characteristics of the sessile ferrofluid droplet under a horizontal magnetic field

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Fundamental Research 2022年第2期2卷 222-229页

作者： Zhaonan Liu Jiandong Zhou Yang Li Xin Zhuo Xiujuan Shi Dengwei Jing State Key Laboratory of Multiphase Flow in Power Engineering and International Research Center for Renewable Energy X^an Jiaotong UniversityXi'an 710049China

In this study,the evaporation characteristics and drying patterns of various sessile ferrofluid droplets on certain substrate under horizontal magnetic fields of controlled intensities are *** effects of droplet concentration and magnetic field intensity on the duration of each evaporation stage and drying patterns of droplets have been systematically *** turned out that a plateau appears at the initial stage of evaporation in the absence of magnetic field and it was found that the plateau value is positively correlated with the concentration of ferrofluid *** the external magnetic field,the evaporation time of droplets decreases,the stage of contact line retreat extends,the stage of late pinning mode shortens,and the deposition area of ferrofluid droplet decreases compared to that of without magnetics *** deposition area increases gradually and becomes more uniform with the increase of magnetic *** decrease of friction force which is due to the decrease of the number of nanoparticles at the contact line under external magnetic field is the main reason for the observed *** found that the coffee ring and the uniform deposition inside the droplet will be destroyed when the magnetic field intensity is higher than a critical *** work has a significant reference value for the evaporation of sessile magnetic fluid droplets under the applied magnetic field,especially when the drying pattern needs to be precisely controlled,such as in spray or biomedicine.

关键词： Ferrofluid Droplet Drying pattern Evaporation characteristics Magnetic field

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Toward practical photoelectrochemical water splitting and CO_(2) reduction using earth-abundant materials

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Journal of Energy Chemistry 2021年第10期30卷 469-488,I0013页

作者： Yubin Chen Ya Liu Feng Wang Xiangjiu Guan Liejin Guo International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityXi’an 710049ShaanxiChina

Photoelectrochemical(PEC)fuel generation from water splitting and CO_(2)reduction(CO_(2)R)utilizing solar energy holds immense potential to solve the current energy and environmental *** the past decades,numerous studies have been devoted to this fast-growing research field,and it is essential to develop efficient photoelectrodes with earth-abundant materials for the practical application of PEC systems.A thorough review of earth-abundant materials and associated devices for PEC fuel generation is beneficial to uncover the inherent obstacles and pave the way for future ***,we summarize the recent progress of earth-abundant light-absorbers and cocatalysts in the PEC *** unbiased configurations and scaling-up strategies of PEC devices using earth-abundant materials are examined.A comparison between PEC water splitting and CO_(2)R is carried out to promote better understanding of the design principles for practical materials and ***,the prospects on advanced materials,underlying mechanisms,and reaction systems of PEC water splitting and CO_(2)R are proposed.

关键词： Solar energy Photoelectrochemical technology Water splitting CO_(2)reduction Earth-abundant materials

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Synergy of porous structure and cation doping in Ta3N5 photoanode towards improved photoelectrochemical water oxidation

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Journal of Energy Chemistry 2021年第1期30卷 343-350,I0011页

作者： Yubin Chen Hongyu Xia Xiaoyang Feng Ya Liu Wenyu Zheng Lijing Ma Rui Li International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityXi’an 710049ShaanxiChina

Herein,a cross-linked porous Ta3N5 film was prepared via a simple solution combustion route followed by a high-temperature nitridation process for photoelectrochemical(PEC) water ***,the metal cations(Mg2+ and Zr4+) were incorporated into the porous Ta3N5 to enhance the PEC *** porous Mg/Zr co-doped Ta3N5 photoanode yielded a photocurrent density of 1.40 mA cm^(-2) at 1.23 V vs RHE,which is 5.6 times higher than that of the dense Ta3N5 *** enhanced performance should be ascribed to the synergistic effect of porous structure and cation doping,which can enlarge the electrochemical active surface area and accelerate the charge transfer by introducing ON substitution ***,Co(OH)2 cocatalyst was loaded on the Mg/Zr-Ta3N5 photoanode to negatively shift the onset potential to 0.45 V vs RHE and further improve the photocurrent density to 3.5 mA cm^(-2)at 1.23 V ***,with a maximum half-cell solar to hydrogen efficiency of 0.45%.The present study provides a new strategy to design efficient Ta3N5 photoelectrodes via the simultaneous control of the morphology and composition.

关键词： Photoelectrochemical water oxidation Ta3N5 Porous structure Doping Solution combustion

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Numerical and experimental research of the characteristics of concentration solar cells

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Frontiers in Energy 2021年第2期15卷 279-291页

作者： Zilong WANG Hua ZHANG Binlin DOU Weidong WU Guanhua ZHANG Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering School of Energy and Power EngineeringUniversity of Shanghai for Science and TechnologyShanghai 200093China

The development of automatic tracking solar concentrator photovoltaic systems is currently attracting growing *** concentration photovoltaic systems(HCPVs)combining triple-junction InGaP/lnGaAs/Ge solar cells with a concentrator provide high conversion *** mathematical model for triple-junction solar cells,having a higher efficiency and superior temperature characteristics,was established based on the one-diode equivalent circuit cell model.A paraboloidal concentrator with a secondary optic system and a concentration ratio in the range of 100X–150X along with a sun tracking system was developed in this *** GaInP/GalnAs/Ge triple-junction solar cell,produced by AZUR SPACE Solar power,was also used in this *** solar cells produced by Shanghai Solar Youth Energy(SY)and Shenzhen Yinshengsheng Technology ***.(YXS)were used as comparison samples in a further comparative study at different concentration ratios(200X–1000X).A detailed analysis on the factors that influence the electrical output characteristics of the InGaP/lnGaAs/Ge solar cell was conducted with a dish-style concentrating photovoltaic *** results show that the short-circuit current(Isc)and the open-circuit voltage(Voc)of multi-junction solar cells increases with the increasing concentration ratio,while the cell efficiency(ηc)of the solar cells increases first and then decreases with increasing concentration *** increasing solar cell temperature,Isc increases,while Voc andηc decrease.A comparison of the experimental and simulation results indicate that the maximum root mean square error is less than 10%,which provides a certain theoretical basis for the study of the characteristics of triple-junction solar cell that can be applied in the analysis and discussion regarding the influence of the relevant parameters on the performance of high concentration photovoltaic systems.

关键词： concentration three-junction solar cell mathematical model electrical properties solar energy

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