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161 results on '"Xu, Tiejun"'

17. Overview of the EAST in-vessel components upgrade

Author

Yao, Damao, Luo, Gangnan, Du, Shijun, Cao, Lei, Zhou, Zibo, Xu, Tiejun, Ji, Xiang, Liu, Changle, Liang, Chao, Li, Qiang, Wang, Wanjing, Zhao, Sixiang, Xu, Yue, Li, Lei, Wang, Zhaoliang, Qi, Xuan Xiao Minjun, Wang, Songke, and Li, Jiangang

Published
2015
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30. Cr-SiNT, Mn-SiNT, Ti-C70 and Sc-CNT as Effective Catalysts for CO2 Reduction to CH3OH.

Author

Bokov, Dmitry Olegovich, Mustafa, Yasser Fakri, Mahmoud, Zaid H., Suksatan, Wanich, Jawad, Mohammed Abed, and Xu, Tiejun

Abstract

The possibility of conversion of CO2 to CH3OH on Ti-C70, Cr-SiNT, Sc-CNT and Mn-SiNT as catalysts is examined through a specific mechanism in gas, DMSO, acetone and ethanol. The activation energies and reaction energies of steps of CO2 conversion to CH3OH on Ti-C70, Cr-SiNT, Sc-CNT and Mn-SiNT are calculated. The separation of H2O and methanol from the surface of these catalysts are much easier than various metal catalysts. The abilities of Ti-C70, Cr-SiNT, Sc-CNT and Mn-SiNT or CO2 conversion to CH3OH are compared with various metal catalysts. The Ti-C70, Cr-SiNT, Sc-CNT and Mn-SiNT as acceptable catalysts with lower over potential are suggested for CO2 conversion to CH3OH. [ABSTRACT FROM AUTHOR]

Published
2022
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35. Investigating the Manufacturing Process of Heat-Treated Nb3Sn-CICC Conductor for CFETR CSMC Modules

Author

Tong, Yunhua, Gao, Xiang, Han, Houxiang, Xu, Tiejun, Wu, Yu, Liu, Xiaoming, Zhong, Long, Fenga, Siqing, and Si, Kaibing

Abstract

The center solenoid model coil (CSMC) of the China fusion engineering test reactor (CFETR) requires a high heat treatment temperature of 650 °C, which would destroy the insulation layer by carbonization and cause coil failure. To avoid this, using the manufacturing technology and routine process of the ITER center solenoid coil as a reference, in this article, a solution is introduced that is applied for manufacturing the CFETR CSMC module. The coil is heat treated before insulation and after winding. A single turn of the heat-treated coil is separated and the wrapping turn insulation is applied, and then the separated layers are reversed back into the integrated coil. To manufacture the integrated coils, the heat-treated coils are molded. After heat treatment, the interlayer separation distance of the Nb3Sn cable-in-conduit conductor in the coil should satisfy the allowable strain range of the superconductor, which is crucial for designing the rotational support structure of the interlayer separation. In addition, to achieve the accurate final shape of the coil and meet the design requirements, as well as to ensure coil contour accuracy after layer by layer separation, the antideformation ability of the coil mold is a key research topic. Herein, mechanical properties of the key components were optimized and numerical calculations and ANSYS simulations were used for statistical analyses. Results from the analyses indicated that the equivalent stress on the device is less than the maximum permissible stress of the raw material. The device was manufactured and compared with a design mold. The overall deformation error was <5%, movement error of the electric frame was <2%, rotation error of rotating was less than ±1° per 360°, levelness between the upper and lower platform was <1 mm, and motion error was less than ±1 mm per 100 mm. These results demonstrated the optimized structure design of the device. In the as-obtained device, the coil could separate a single turn and wrapping turn insulation could be applied. Parameters of the manufactured coil satisfied all the CSMC design requirements; these results indicate that the proposed device is suitable for manufacturing the CFETR CSMC module coil.

Published
2023
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36. Simulation study of the influence of wall ablation on arc behavior in a low-voltage circuit breaker

Author

Ma, Qiang, Rong, Mingzhe, Murphy, Anthony B., Wu, Yi, and Xu, Tiejun

Subjects
Fluid dynamics -- Analysis, Electric circuit-breakers -- Analysis, Plasma arc welding -- Models, Business, Chemistry, Electronics, Electronics and electrical industries
Abstract

This paper focuses on the numerical research of the influence of polymer (polyoxymethylene) on the arc behavior during arc-motion process. The mathematical model of 3-D air-arc plasma considering the ablation of sidewalls is built based on magnetic hydrodynamics. The mass-fraction equation is introduced to the model on the basis of traditional mass, momentum, and energy-balance equations. The influence of wall ablation on the thermodynamic and transport properties of air-polymer mixtures is considered in this paper. The distributions of temperature field, pressure field, and mass fraction in the arc chamber are calculated. The simulation results indicate that the vapor concentration behind the arc column is higher than that in front of the arc column because of the existence of 'vortex' in the arc chamber. The use of polymers could accelerate arc movement and reduce the probability of occurrence of back-striking. Using polymers can also increase arc voltage, which can be explained by the change of electrical conductivity for air-polymer vapor mixtures. Index Terms--Arc behavior, arc simulation, low-voltage breaker, wall ablation.

Published
2009

39. Hydraulic assessment of cooling circuit for CFETR W/Cu divertor

Author

Wu Songtao, Mao Xin, Peng Xuebing, Qian Xinyuan, Song Wei, Yao Damao, Liu Peng, and XU Tiejun (许铁军)

Subjects
Materials science, Critical heat flux, Mechanical Engineering, Circuit design, Divertor, Nuclear engineering, Fusion power, Coolant, Nuclear Energy and Engineering, Flow velocity, Heat transfer, General Materials Science, Potential flow, Civil and Structural Engineering
Abstract

Divertor, whose main functions are to sustain extremely high heat load and to exhaust impurity, is a key component in fusion reactor. CFETR divertor is currently under engineering design and technical validation phase. In this study, a cooling circuit design is proposed to obtain sufficient heat removal capability for CFETR divertor. The cooling circuit consists of two main modules which are outer target module and inner target module. Considering the complexity of the parallel cooling circuit concept, hydraulic characteristics is assessed and optimized for enough heat transfer capability and critical heat flux margin. Assessment of the hydraulic characteristics for the cooling circuit is performed by investigating flow velocity and local pressure on channels’ cross-sections. Uniform flow velocity of 10 m/s and acceptable critical heat flux margin higher than 1.4 in PFU coolants channels are obtained after optimization meeting the design requirements of the divertor.

Published
2021

41. Interface design of the blanket system for CFETR

Author

Lei, Mingzhun, primary, Song, Yuntao, additional, Ni, Xiaojun, additional, Wu, Xinghua, additional, Shen, Junsong, additional, Liu, Sumei, additional, Liu, Songlin, additional, Wang, Xiaoyu, additional, Cheng, Yong, additional, Xie, Yuanlai, additional, Wang, Xiaojie, additional, Liu, Liang, additional, Chen, Gen, additional, Xu, Tiejun, additional, and Lu, Kun, additional

Published
2020
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45. Development and performance test of CuCrZr/316 L explosive welding plate for EAST Lower divertor heat sink

Author

Duan Mianjun, Sun Wenyan, Han Le, Xu Tiejun, Cao Lei, and Yao Damao

Subjects
Fusion, Materials science, Mechanical Engineering, Divertor, chemistry.chemical_element, Heat sink, 01 natural sciences, 010305 fluids & plasmas, Explosion welding, Nuclear Energy and Engineering, chemistry, 0103 physical sciences, General Materials Science, Composite material, 010306 general physics, Wall thickness, Dissolution, Helium, Civil and Structural Engineering, Leakage (electronics)
Abstract

As a key material for manufacturing EAST lower divertor heat sink, high-quality CuCrZr/316 L bonding plate is preferred to be manufactured by explosive welding, which is advantageous in zero input heat without deteriorating the material performance of CuCrZr and 316 L. In accordance with various detections and analyses of CuCrZr/316 L after the explosive welding: metallographic phase and electron microscope analysis showed the bonding interface contains no cavity or Cu/Fe metallic mutual dissolution; tensile stress of the bonding interface is higher than that of the CuCrZr material; a hollow heat sink sample (3 mm wall thickness) made of this material can withstand 4.5 MPa water pressure without deformation or leakage, and has been successfully undergone helium leak detection (200℃, 1 MPa, 1 × 10−11 m3/s). Such test results showed the bonding plate by explosive welding met all high quality requirements on fusion engineering that it can be applied to EAST divertor reliably.

Published
2020

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