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Research Square 2021年

作者： Zhao, Liang Lei, Mohan Ren, Hongdi Wang, Jinshi Wang, Shuai Li, Ben Q. Yang, Jun Mei, Xuesong Xi'an Jiaotong University China State Key Laboratory for Manufacturing Systems Engineering Xi'an Jiaotong University Xi'An710049 China Shaanxi Key Laboratory of Intelligent Robots Xi'an Jiaotong University Xi'An710049 China School of Mechanical and Precision Instrument Engineering Xi'an University of Technology 710048 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Department of Mechanical Engineering College of Engineering and Computer Science University of Michigan MI48128 United States

Spindles in precision boring machine often work in low speed and heavy load without internal cooling, and the thermal error is nonnegligible. So an external cooling system was designed, and the effectiveness of the designed scheme needs to be preliminarily verified by simulation before building the cooling system. Thermal simulations of the spindle with an external cooler require calculating the thermal resistance of the thermal grease-coated interface between the cooler and spindle. Models describing the contact thermal resistance and total thermal resistance for metal contact filled with silicone grease based on solid-liquid interface force equivalence were described in this paper, and experiments were also conducted to verify the accuracy of these models. The contact thermal resistances between the cast iron/copper and silicone grease on flat or arc surfaces were calculated, and the bulk thermal resistance of the silicone grease layer was calculated. The total heat transferred between the cooler and the silicone grease-coated interface of the spindle were calculated. Heat transfer and heat generation in the spindle were calculated, and a finite element model was established to verify the effectiveness of the designed external cooling scheme. Finally, results from experiments for the spindle in different conditions show that the external cooling system decreases the time to reach thermal equilibrium by more than 60%. The RMSE of the simulated thermal elongation is less than 5.7044 μm when the rotating speed of 3000 rpm, and is less than 3.9714 μm when the rotating speed is 1500 rpm. © 2021, CC BY.

关键词： Cooling

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Performance of cone meter for measuring cryogenic fluid considering cavitation

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International Journal of Fluid Machinery and Systems 2019年第1期12卷 12-21页

作者： He, Denghui Chang, Zhuang Bai, Bofeng Chen, Senlin Guo, Pengcheng State Key Laboratory of Eco-hydraulic in Northwest Arid Region Xi’an University of Technology NO.5 South Jinhua Road Xi’an710048 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University No.28 Xianning West Road Xi’an710049 China

The performance of the cone meter when measuring the cryogenic fluid was investigated by numerical simulation. The results show that the discharge coefficient and pressure loss coefficient of the cone meter are almost constant when the Reynolds number in the "stable region". The cryogenic fluids, especially the liquid hydrogen, have wider stable Reynolds number ranges than the water. There is little effect of cavitation on the discharge coefficient and pressure loss coefficient at the initial stage of cavitation. Thus the effect of slight cavitation on the measurement error of the flow rate is small, whose relative error is less than ±0.5% in present cases. This study opens a new avenue for measuring the flow rate of the cryogenic fluid. © 2019, Turbomachinery Society of Japan. All rights reserved.

关键词： Cavitation

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On-Line Measurement of Ultralow Mass Concentration Particulate Based on Light Scattering Coupled with Beta Ray Attenuation Method

SSRN

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SSRN 2022年

作者： Liu, Xiaowei Huang, Yubo Wang, Zhaofeng Jiang, Meng Zhou, Zijian Xu, Minghou Han, Jinke Yang, Bin Fan, Xinfeng State Key Laboratory of Coal Combustion School of Energy and Power Engineering Huazhong University of Science and Technology 1037 Luoyu Road Wuhan430074 China JXIC Energy Technology Research Institure Nanchang330000 China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering University of Shanghai for Science and Technology Shanghai200093 China Wuhan Tianhong Environmental Protection Industry Co. Ltd Yuhong Environmental Protection Science and Technology Industrial Park No.11 Huashiyuan North Road Miaoshan District Donghu high tech Development Zone Wuhan430074 China

Light scattering method is the most commonly used method for on-line measurement of ultralow particulate matter mass concentration. However, when the particle characteristics change, the effectiveness of the empirical relationship decreases, which would lead to a sizeable deviation. To accurately measure the mass concentration of particulate matter in real-time, a coupling measurement idea of light scattering and beta-ray attenuation is proposed. The beta-ray attenuation is little affected by particle properties and accurately reflects the average PM mass concentration in the measured period. The single calibration method (M1), periodic calibration method (M2), average calibration method (M3), and asymmetric factor calibration method (M4) are formed based on the coupling idea. The results of all methods are perfect when the particle size is unchanged. However, when the particle sizes fluctuate frequently, the results of M1, M2, and M3 deviate seriously from the actual value, and the applicable working conditions have limitations. The results of M4 are in good agreement with the actual value, and the effectiveness is not limited by the particle size. Finally, the prototype based on experimental exploration was developed and had been continuously operated for more than 528 hours at a 1000 MW unit of a coal-fired power plant. © 2022, The Authors. All rights reserved.

关键词： Particle size

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Numerical simulation of high temperature gas cooled reactors on less of coolant accident 18

Numerical simulation of high temperature gas cooled reactors...

引用

18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2019

作者： Zhang, Shuangbao Li, Liangxing Xie, Wei Wang, Kailin State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xianning West Road 28# Xi’an city710049 China

The high temperature gas-cooled reactor (HTR) is well known for its prominent inherent safety, high efficiency and low carbon environmental protection, which has been identified as one of the candidates for the Generation IV nuclear energy system technology. Accurate and reliable thermal hydraulic analysis is of great significance to the system design and safe operation of HTR. Based on the coolant flow and heat transfer process in the core of HTR, this study establishes a three-dimensional model by using CFD (Computational Fluid Dynamics) software firstly, and the flow and heat transfer process of helium coolant is simulate in the core. The temperature distribution of HTR is calculated at steady state, and the calculation results were compared with the related published results for validation and verification. After that, the models are employed to study the thermal hydraulic characteristics under the loss of coolant accident of HTR. The results show that as the coolant passes through the core from top to bottom, helium is continuously heated, and the temperature increases from top to bottom. The temperature reached a maximum at the core exit position of 1032.75 K. It stated that the model can be employed to simulate the thermal hydraulic analysis for HTR. The calculation results of the loss-of-coolant, indicates t as the flow rate decreases, the coolant temperature rises gradually. When the coolant is completely lost, the temperature reaches a maximum of 1723.19 K, and it is still lower than the design limit of 1893.15 K. © 2019 American Nuclear Society. All rights reserved.

关键词： Coolants

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The theoretical and numerical analysis on a multi-blade liquid lead pump 27

The theoretical and numerical analysis on a multi-blade liqu...

引用

27th International Conference on Nuclear engineering: Nuclear power Saves the World!, ICONE 2019

作者： Wang, Kailin Li, Liangxing Xie, Wei Zhang, Shuangbao State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xianning West Road 28# Xi'an city710049 China

ISBN: (纸本)9784888983051

Lead or lead-alloy cooled fast reactors (LFRs) have been proved to be the most promising Generation IV reactors with high performance in neutronics, thermal hydraulics and security features. Small forced circulation modular LFRs is one of the potential candidates for LFRs development which has attracted particular attention in recent years. When lead-bismuth eutectic (LBE) is used as coolant, the primary LBE pump is a key conveying equipment, and therefore the hydraulic performance of LBE pump is great important to the safety of LFR. Motivated by improving the hydraulics performance of LBE pump, this paper presents a theoretical and computational analysis on an axial flow pump. The guide blades are set at the outlet of the impeller to eliminate the rotational motion of the liquid LBE and transform the kinetic energy of the rotational motion into pressure energy. The rotation angle of the blade is optimized based on the theoretical analysis to reduce the vortex and raise efficiency. As well, the outlet speed and pressure parameters of each part in the pump are calculated. After that, a three-dimensional model of the modified pump is established by using CFD software and the flow characteristics of LBE in the pump are simulated. Albeit the high velocity liquid LBE alloy still exists in the side of pump shroud, some erosion-related issues remain to be fully addressed. The results of the study show that the axial LBE pump could be used as a viable solution for the design of the new generation of small module reactor primary pump from a thermo-fluid dynamic point of view. © 2018-2019 by JSME

关键词： Pumps

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Ultrafine polycrystalline titania nanofibers for superior sodium storage

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Journal of Energy Chemistry 2019年第11期28卷 153-161页

作者： Zhidan Diao Daming Zhao Chunxiao Lv Hongli Liu Dongjiang Yang Shaohua Shen International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityXi’an 710049ShaanxiChina School of Environmental Science and Engineering Collaborative Innovation Centerfor Marine Biomass FibersMaterials and Textiles of Shandong ProvinceQingdao UniversityQingdao 266071ShandongChina

Sodium ion batteries have a huge potential for large-scale energy storage for the low cost and abundance of sodium resources. In this work, a novel structure of ultrafine polycrystalline TiO2 nanofibers is prepared on nickel foam/carbon cloth by a simple vapor deposition method. The as-prepared TiO2 nanofibers show excellent performance when used as anodes for sodium-ion batteries. Specifically, the TiO2 nanofibers@nickel foam electrode delivers a high reversible capacity of 263.2 m Ahg^-1 at 0.2 C and maintains a considerable capacity of 144.2 m Ahg^-1 at 10 C. The TiO2 nanofibers@carbon cloth electrode also shows excellent high-rate capability, sustaining a capacity of 148 m Ahg^-1 after 20 0 0 cycles at 10 C. It is believed that the novel nanofibrous structure increases the contact area with the electrolyte and greatly shortens the sodium ion diffusion distance, and meanwhile, the polycrystalline nature of nanofibers exposes more intercalation sites for sodium storage. Furthermore, the density functional theory calculations exhibit strong ionic interactions between the exposed TiO2(101) facets and sodium ions, leading to a preferable sodiation/desodiation process. The unique structural features endow the TiO2 nanofibers electrodes great advantages in rapid sodium storage with an outstanding high-rate capability.

关键词： Polycrystalline titania Nanofibers Sodium storage High-rate capability

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Three-dimensional modeling and thermal hydraulic analysis of high temperature gas-cooled reactor core 27

Three-dimensional modeling and thermal hydraulic analysis of...

引用

27th International Conference on Nuclear engineering: Nuclear power Saves the World!, ICONE 2019

作者： Zhang, Shuangbao Li, Liangxing Xie, Wei Wang, Kailin State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xianning West Road 28# Xi'an city710049 China

ISBN: (纸本)9784888983051

The high temperature gas-cooled reactor (HTR) is an advanced reactor with the characteristics of Generation IV nuclear energy system which has attracted wide attention due to the excellent performances of inherent safety, economy, high efficiency and low carbon environmental protection. Accurate and reliable thermal hydraulic analysis is of great significance for studying the flow and heat transfer in the core of HTR. Based on the coolant flow and heat transfer process in the core of HTR, this study establishes a three-dimensional coupled model by using CFD (Computational Fluid Dynamics) software firstly, and the flow and heat transfer process of helium coolant is simulate in the core. The temperature variation in the reactor is calculated under the conditions of steady-state operation of the HTR core, and the calculation results by the present models were compared with calculated results from the benchmark software of Thermix and the related published results. The results showed that the average temperature of the outlet section is 759.6 ℃, and the maximum relative error with the published data is 1.25%. The steady-state results under the full power conditions based on the three-dimensional model are in good agreement with the calculation data from those of THERMIX. It stated that the three-dimensional model can be employed to simulate the thermal hydraulic analysis for HTR. On this basis, the heat transfer characteristics of core is simulated under 50% full power, and the are result helpful for the operation and design of HTR. © 2018-2019 by JSME

关键词： Porous materials

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Experimental study on pressure and temperature distribution characteristics of subcritical and supercritical water in vertical flow channel

International Journal of Fluid Engineering

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International Journal of Fluid engineering 2024年第4期1卷 56-64页

作者： Hui Jin Huibo Wang Yi Li Petr A.Nikrityuk State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityShaanxi 710049China Mechanical Engineering Department Eindhoven University of TechnologyEindhovenNetherlands Chemical and Materials Engineering Department University of AlbertaEdmontonAlberta T6G 2R3Canada

To enhance knowledge about efficiency improvement and reactor optimization in supercritical water gasification,an experimental system was designed to study the pressure and temperature distribution of subcritical and supercritical water in a channel,representing a simplified continuous *** pressure drop and temperature distribution along and perpendicular to the forced flow are studied by the measure points inserted inside the test *** results show that the pressure drop in the test section is linearly negatively correlated with the average enthalpy of the inlet and outlet,eventually reaching negative values(-0.177 MPa)at high average enthalpy(2300 kJ kg^(-1)).Temperature and specific enthalpy along the flow direction match theoretical estimates,except near the pseudocritical *** subcritical cases,horizontal temperature differences are positively correlated with enthalpy differences and mass flow rates but remain nearly constant in supercritical ***,with fluid temperature rising from the pseudocritical point,the horizontal temperature difference first increases,then decreases,and reaching a peak of 4.29 K at a fluid temperature of 664 *** of the obtained data reveals that the negative correlation and values of the pressure drop are caused by fluid volume ***,fluid volume expansion,near-wall natural convection,and turbulent forced flow fluctuations contribute to horizontal temperature non-uniformity.

关键词： flow distribution channel

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Review on development of carbon nanotube field emission cathode for space propulsion systems

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High Voltage 2020年第4期5卷 409-415页

作者： Chao Huo Feng Liang An-bang Sun Science and Technology on Combustion Internal Flow and Thermal-structure LaboratorySchool of AstronauticsNorthwestern Polytechnical UniversityXi'anShaanxiPeople's Republic of China Faculty of Metallurgical and Energy Engineering Kunming University of Science and TechnologyKunmingPeople's Republic of China State Key Laboratory of Electrical Insulation and Power Equipment School of Electrical EngineeringXi'an Jiaotong UniversityXi'an 710049People's Republic of China

In recent years,small-size,low-weight aerospace propulsion systems have developed rapidly for space exploration,on-orbit scientific instruments and extra space missions,while additional electron emission devices are commonly required in those propulsion *** nanotube(CNT)based field emission cathodes exhibit extraordinary field emission properties and are regarded to be an ideal alternative of conventional thermionic or hollow *** this study,the authors give an overview of present status of researches on CNT-based electron emission cathodes for utilising as neutralisers or electron sources particularly in space electric propulsion systems,the theory and characteristics of CNT are also ***,challenges,problems and possible solutions before actual applications of CNT in a space mission are discussed accordingly.

关键词： field neutral emission

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Experimental Study on the Boiling Heat Transfer Characteristics of R134a in a Helically Coiled Tube

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Kung Cheng Je Wu Li Hsueh Pao/Journal of engineering Thermophysics 2019年第3期40卷 587-593页

作者： Niu, Xiao-Juan Yuan, Huai-Jie Quan, Chen Bai, Bo-Feng Zhao, Liang State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

The characteristics of R134a boiling heat transfer in a vertically helically coiled tube are studied. The experimental parameters are as follows: the heat flux is 10∼60 kW•m-2, the mass flux is 195∼400 kg•m-2 •s-1, the pressure is 0.8∼1.1 MPa, and the outlet vapor quality is 0.1∼0.9. The experimental data are compared with the existing correlations of boiling heat transfer coefficient. Based on the analysis of boiling heat transfer mechanism, a new correlation for boiling heat transfer in coiled tube is proposed. The circumferential distribution characteristics of wall temperature and heat transfer coefficient are analyzed. The wall temperatures at inner and top side are relatively higher, and the heat transfer coefficients at the bottom and the outer side are relatively higher. The local heat transfer coefficients are compared with the new correlation proposed in this paper. The results show that the heat transfer coefficients at top and bottom sides can be predicted by the new correlation. However, the new correlation underestimates the heat transfer coefficient at the outer side and overestimates that at the inner side, the deviations are 16.6% and -11.9% respectively. © 2019, Science Press. All right reserved.

关键词： Heat transfer coefficients

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