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Design and Optimal Thermal Efficiency Contrastive Analysis on Closed Brayton Cycle Systems with Different Fluids of Fluoride-Salt-Cooled High-Temperature Advanced Reactor

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SSRN 2022年

作者： Li, Xinyu Zhang, Dalin Yun, Shichang Zhou, Xingguang Jiang, Dianqiang Lv, Xindi Feng, Zhenyu Wu, Wenqiang Tian, Wenxi Qiu, Suizheng Su, Guanghui Zhao, Quanbin Liu, Xiuting State Key Laboratory of Multiphase Flow in Power Engineering Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology School of Nuclear Science and Technology Xi’an Jiaotong University Xi’an710049 China CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology Nuclear Power Institute of China Chengdu610213 China

To match the advantages of Fluoride-Salt-cooled high-Temperature Advanced Reactor, the closed Brayton cycle system was selected as the energy conversion system, and the thermodynamic analysis, conjugate gradient optimization, and exergy analysis were performed. The pinch point constraint method based on simultaneous equations was proposed to improve the calculation efficiency and ensure the unity of comparison standards, and the exergy analysis was used to quantify and optimize the exergy losses for the equipment. For the simple regenerative cycle configuration, the thermal efficiency and mass flow rate of the cycle system with various fluids (far-critical fluids: air, nitrogen, helium, and argon, near-critical fluids: carbon dioxide, sulfur hexafluoride, propane, and xenon) were analyzed. The results of the thermodynamic analysis show that the thermal efficiency of the sulfur hexafluoride cycle is the highest and reaching 46.6% with the simple regenerative cycle configuration. The thermal efficiency of the far-critical fluid cycle is more sensitive to turbine efficiency. The results of the exergy analysis show the CO2 cycle has the highest potential to improve thermal efficiency, which has the highest improvement from 43.48% to 49.31. with the recompression process. The method and conclusion of this paper can provide references for the design and optimization of the Brayton {1. cycle system © 2022, The Authors. All rights reserved.

关键词： Carbon dioxide

Design and Optimal Thermal Efficiency Analysis on Closed Brayton Cycle System of Fluoride-Salt-Cooled High-Temperature Advanced Reactor (Fustar)

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SSRN 2022年

作者： Li, Xinyu Zhang, Dalin Yun, Shichang Zhou, Xingguang Jiang, Dianqiang Lv, Xindi Feng, Zhenyu Wu, Wenqiang Tian, Wenxi Qiu, Suizheng Su, G.H. Zhao, Quanbin Liu, Xiuting State Key Laboratory of Multiphase Flow in Power Engineering Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology School of Nuclear Science and Technology Xi’an Jiaotong University Xi’an710049 China CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology Nuclear Power Institute of China Chengdu610213 China

To match the advantages of Fluoride-Salt-cooled high-Temperature Advanced Reactor (FuSTAR): the high temperature, inherent safety, compact structure, and modularization, the closed Brayton cycle system was selected as the energy conversion system, and the enthalpy analysis, conjugate gradient optimization, and exergy analysis were performed. The pinch point constraint method based on simultaneous equations was proposed to improve the calculation efficiency and ensure the unity of comparison standards, and the exergy analysis was used to quantify and optimize the exergy losses for the equipment. For the simple regenerative cycle configuration, the thermal efficiency and mass flow rate of the cycle system with various fluids (far-critical fluids: air, nitrogen, helium, and argon, near-critical fluids: carbon dioxide, sulfur hexafluoride, propane, and xenon) were analyzed, at the highest thermal efficiencies. The results of enthalpy analysis show that the thermal efficiency of the sulfur hexafluoride cycle is the highest with the simple regenerative cycle configuration. The thermal efficiency of the far-critical fluid cycle is more sensitive to turbine efficiency. The exergy analysis shows the CO2 cycle has the highest potential to improve thermal efficiency. The method and conclusion of this paper can provide references for the design and optimization of the Brayton {1. cycle system. © 2022, The Authors. All rights reserved.

关键词： Enthalpy

Thermal Characteristics and Structural Parameters Optimization of Apg/Cu/Pcm Integrated Architecture

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SSRN 2024年

作者： Su, Lizheng Zhang, Tianning Li, Xiaoyang Li, Dong Jiang, Xinyu Xie, Zhongnan Xi'an Electronic Engineering Research Institute Xi’an710100 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi’an710049 China State Key Laboratory of Nonferrous Metals and Processes GRINM Group Co. Ltd. Beijing100088 China

The challenges faced by radar seeker primarily stem from inadequate heat dissipation in chips and excessive weight. To address these issues, this study introduces a novel integrated phase-change heat sink architecture, composed of a copper alloy matrix, annealed pyrolytic graphite (APG), and phase-change materials (PCMs) serving as heat conduction reinforcements. The numerical analysis of the heat dissipation performance of this architecture is conducted using Fluent software. The study evaluates the impact of APG anisotropy, APG/Cu interface thermal resistance, APG thickness, and surface area on the heat conduction efficiency. Results demonstrate that APG facilitates a uniform in-plane temperature distribution, allowing PCMs to absorb heat more evenly. Consequently, APG proves effective in enhancing heat dissipation and safeguarding chips from high temperatures. In comparison to a pure copper component, the APG/Cu/PCM structure reduces chip temperature by a substantial 56.27%. Furthermore, increasing the surface area of APG generally contributes to an enhanced heat transfer capability of entire architecture. The paper presents a quantitative relationship between APG surface area and optimal thickness. Importantly, APG satisfies the lightweight requirement, further emphasizing its suitability for addressing the thermal challenges in radar seeker structures. © 2024, The Authors. All rights reserved.

关键词： Phase change materials

Development of a Two-Phase flow Solver with Drift-Flux Model Based on Openfoam: Validation Against Single/Two-Phase and Boiling flow

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SSRN 2024年

作者： Wu, Wenqiang Zhang, Dalin Huang, Tao Du, Peng Zhou, Lei Wang, Bo Deng, Jian Qiu, Zhifang Tian, Wenxi Qiu, Suizheng Su, Guanghui State Key Laboratory of Multiphase Flow in Power Engineering Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology School of Nuclear Science and Technology Xi’an Jiaotong University Shaanxi Xi’an710049 China Nuclear Power Institute of China 328 Changshun Avenue Chengdu610213 China

Based on the open-source platform OpenFOAM, this paper implements a two-phase flow solver for drift flux models with realistic closure relations. The solver inherits the numerical method from the OpenFOAM framework, adopts the PIMPLE algorithm, and follows its discrete and matrix-solving criteria, focusing on developing a two-phase flow model and constitutive models. The drift velocity model is based on Ishii and his collaborators’ work. The remaining models, such as wall friction, wall heat transfer, interfacial heat and mass transfer, are taken from TRACE Theory Manual. To fulfill the condition of conjugate heat transfer between fluid and solid, a virtual solid heat transfer function is developed under the premise of a single-domain solver. Extensive and successful validation has been conducted involving single-phase, two-phase, and boiling flow heat transfer phenomena by comparing with experimental data or typical system codes, and the two-phase flow solver's success has been demonstrated in several aspects. © 2024, The Authors. All rights reserved.

关键词： Two phase flow

Experimental study on the contribution of included/excluded minerals to particulate formation during coal char combustion

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Fuel 2023年第1期346卷

作者： Shang, Yimin Liu, Siqi Niu, Yanqing Zhu, Guangqing Cheng, Zening Hui, Shi'en State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Shaanxi710049 China China Nuclear Power Technology Research Institute Shenzhen518031 China Zhundong Energy Research Institute Xinjiang Tianchi Energy Co. Ltd. Xinjiang831100 China

The contributions of included and excluded minerals to particulate matter formation are quantified in this work. By devolatilization of three typical Chinese coals, three coal chars with low (LA), moderate (MA), and high ash (HA) content (with both included and excluded minerals) were prepared, from which three float coal chars with low (LA−), moderate (MA−), and high ash (HA−) content (without excluded minerals) were separated by density differentiation method. The coal chars before and after separation were burned in a drop-tube furnace at 1.00 K, the results of three float coal chars can directly reveal the contribution of included minerals, and the comparison of two kinds of chars with and without excluded minerals would reveal the excluded mineral contribution to ash distribution. The size distributions of the combustion-generated ash particle were obtained from the combination of ELPI+ and laser particle-size analyzer. The fractions of included/excluded minerals were obtained from SEM images. The results from the combustion of the float chars indicate the physical transformation of included minerals, while the results from original coal chars involve the transformation of both included and excluded minerals. Results indicate that the distribution of ash particles from included minerals for HA− char possesses a single peak, while the ash distributions of MA− and LA− char show a bi-modal shape. The excluded minerals in LA and MA chars mainly contribute to the ash emissions with sizes larger than 80 μm. The contribution from excluded minerals reach 86% to the ash particles of 205 μm for HA char, 54% for MA char and 51. for LA char. The number fractions of included minerals continuously decrease with a transformation into excluded minerals during char dynamic combustion. © 2023 Elsevier Ltd

关键词： Minerals

Stress analysis of heat exchange tube with inner and outer fins under convection heat transfer conditions

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Huagong Xuebao/CIESC Journal 2011年第SUPPL. 1期62卷 86-91页

作者： Ji, Yanpeng Ma, Ting Zeng, Min Wang, Qiuwang State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 Shaanxi China

The heat exchange tube with inner and outer fins has been widely applied in industry in order to enhance the performance of heat exchangers. When it is used in high temperature environment, the security must be considered. A three-dimension model was established to simulate the thermal stress by software ANSYS. The results indicated that the main factor, which had effect on the stress and deformation, was temperature and the maximum stress occurred at the joint location between inner fins and tubes. The inner pressure distribution of tube could enhance the effect of stress. On the contrary, the outer could weaken the effect. © All Rights Reserved.

关键词： Finite element method

Application of high resolution finite difference scheme in direct numerical simulation of turbulent flow

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Kung Cheng Je Wu Li Hsueh Pao/Journal of engineering Thermophysics 2007年第5期28卷 859-861页

作者： Ma, Liang-Dong Li, Zeng-Yao Tao, Wen-Quan State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Xi'an 710049 China

A direct numerical simulation of a fully developed turbulent flow and heat transfer in a square duct is studied based on high resolution finite difference scheme. The flow and temperature fields are obtained at a turbulent Reynolds number of 400 based on the mean friction velocity and the hydraulic diameter, and the Prandtl number (Pr) of 0.71. Two kinds of point-stencil method are used for the spatial derivatives of the pressure Poisson equation, i.e. the second-order and fourth-order central difference, respectively. The results show that satisfactory solutions can be obtained in the present DNS simulation with coarse grids compared with the method of second-order central difference. And the solutions from the two kinds of point-stencil method for pressure Poisson equation are consistent with the second-order central difference being more economical in saving computation time.

关键词： Pipe flow

Research on surface damage of solid material subjected to high speed liquid impact

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Binggong Xuebao/Acta Armamentarii 2009年第SUPPL. 2期30卷 139-144页

作者： Xie, Yong-Hui Wang, Yong Chen, Jian-Hui Zhang, Di State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Shaanxi Xi'an 710049 China

In order to study the surface damage of solid material subjected to the high speed liquid impact, both numerical and experimental methods were established. The smoothed particle hydrodynamics and finite element analysis were used to calculate the material damage. The conditions of PMMA and steel were analyzed to obtain the dynamic stress and strain distribution during impact. An experiment apparatus was build. The velocity of the impact jet was measured using a high speed camera and the apparatus. A digital microscope was used to measure the three dimensional profile of the sample before and after high speed liquid impact up to 600 m/s. The dimensions of damage area were recorded and analyzed statistically. Based on the statistical results, the performance of the materials resisting liquid corrosion was evaluated.

关键词： High speed cameras

New Mg-based Material as a Promising Hydrogen Storage Candidate: Synthesis, Characterization and Hydrogen Storage Behavior

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New Mg-based Material as a Promising Hydrogen Storage Candid...

第五届世界氢能技术大会(WHTC201.)

作者： Zhen Wu Fusheng Yang Zaoxiao Zhang State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049P. R. China School of Chemical Engineering and TechnologyXi’an Jiaotong UniversityXi’an 710049P. R. China State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityXi’an 710049P. R. China School of Chemical Engineering and Technology Xi’an Jiaotong UniversityXi’an 710049P. R. China

Mg and Mg-based metal hydrides are viewed as one of the most promising hydrogen storage materials due to their high capacity,light weight,low price and little impact on the ***,the practical application is obstructed by their high stability,which results in the bad kinetics and high reaction temperature,especially the high operating temperature.

关键词： Magnesium Hydrogen storage Thermodynamics Physisorption