Numerical simulation of turbulent mixing process of polydisperse quartz particle(particle size distribution in the range of 0.1-0.4 mm)flow with Ar and Ar-H2 plasma generated by radio frequency inductively coupled pla...Numerical simulation of turbulent mixing process of polydisperse quartz particle(particle size distribution in the range of 0.1-0.4 mm)flow with Ar and Ar-H2 plasma generated by radio frequency inductively coupled plasma(RF-ICP)torch has been made.An approximate two-stage approach has been proposed to calculate the spatial-temporal distributions of temperature and resulting thermal stress in quartz particles during dynamic heating in polydisperse plasma flow.The influence of working gas compositions,particle size distributions,injection angle and flow rate of carrier gas on the thermal destruction conditions of quartz particles has been determined under different particle feed rates.It is found that all the solid quartz particles(0.1-0.4 mm)could be thermal destructed without overheating in RF-ICP torch system,when the hydrogen volume fraction in working gases is more than 1.5%-2%and particle feed rate is in a certain range.The values of the maximum and minimum feed rates have been determined under different hydrogen volume fractions.An optimal particle injection angle and flow rate of carrier gas is found around 50°-60°and 160-220 slpm,under which the value of maximum equivalent thermal stress in quartz particles is highest.展开更多
In the present work,the turbulent mixing process of a polydisperse quartz particle flow with a plasma stream generated by a radio-frequency(RF)inductively coupled plasma torch was numerically studied.The thermobaric s...In the present work,the turbulent mixing process of a polydisperse quartz particle flow with a plasma stream generated by a radio-frequency(RF)inductively coupled plasma torch was numerically studied.The thermobaric stress in the quartz particles under dynamic heating in a heterogeneous plasma flow was determined by a two-stage approximation approach.The effect of the presence of vacuoles in natural quartz on the particle thermobaric destruction conditions was studied.It was found that the equivalent thermal and baric stresses in quartz particles may significantly increase in the presence of vacuoles within a small gas volume fraction.The influence of the regime and energetic working conditions of an RF inductively coupled plasma torch system on the particle thermobaric destruction conditions was examined,and a recommendation was given to promote the degree of thermobaric destruction of quartz particles,which is of substantial importance for improving the overall enrichment efficiency of quartz concentrates.展开更多
THE Torch Festival is the most significant and grandest celebration for all Yi communities across China’s Yunnan,Guizhou,and Sichuan provinces,with a history spanning over a thousand years.It reflects the Yi people’...THE Torch Festival is the most significant and grandest celebration for all Yi communities across China’s Yunnan,Guizhou,and Sichuan provinces,with a history spanning over a thousand years.It reflects the Yi people’s long-standing reverence for fire.Originating from the Yi ancestors’worship of fire,the festival was intended to drive away pests and evil spirits,protect crops,and represent prayers for a bountiful harvest.展开更多
In this paper, a new MPT(microwave plasma torch) device has been used as a atomizer for atomic fluorescence spectrometry. Spme elements, such as Zn, Cd, Hg, Pb, As, Co, Mg, Cu, Ag, Mn, Fe have been investigated in det...In this paper, a new MPT(microwave plasma torch) device has been used as a atomizer for atomic fluorescence spectrometry. Spme elements, such as Zn, Cd, Hg, Pb, As, Co, Mg, Cu, Ag, Mn, Fe have been investigated in detail.展开更多
A novel plasma torch nitriding technology was applied for the first time to improve the surface properties of M2 high-speed steel by adjusting different experimental parameters.The nitrogen content,precipitate,microst...A novel plasma torch nitriding technology was applied for the first time to improve the surface properties of M2 high-speed steel by adjusting different experimental parameters.The nitrogen content,precipitate,microstructure,mechanical property,and corrosion resistance of the nitrided layer were comprehensively analyzed using an ONH analyzer,scanning electron microscope(SEM),micro-area X-ray diffractometer,transmission electron microscope(TEM),Vickers microhardness tester,high-temperature wear tester,3D profilometer,tensile testing machine,and electrochemical workstation.The research results show that the novel plasma torch nitriding technology can achieve synergistic strengthening of nitrogen,carbon,and alloying element solid solution,precipitation strengthening,and martensitic structure on the surface of M2 high-speed steel.The nitrogen content on the specimen surface increased up to 0.17%,while the size and area of carbides were reduced by 89%and 86%,respectively,indicating a transformation towards fine nitrogen-rich precipitates.Compared to the original M2 steel,the nitrided specimens exhibited significant improvements in overall performance.The hardness increased from 228 HV_(0.2)to a maximum of 795 HV_(0.2),the wear coefficient decreased from a maximum of 0.8 to 0.49,the tensile strength increased from 753 MPa to a maximum of 934 MPa,and the corrosion current density decreased from 1.2×10^(−5)to a minimum of 1.9×10^(−6)A/cm^(2).展开更多
文摘Numerical simulation of turbulent mixing process of polydisperse quartz particle(particle size distribution in the range of 0.1-0.4 mm)flow with Ar and Ar-H2 plasma generated by radio frequency inductively coupled plasma(RF-ICP)torch has been made.An approximate two-stage approach has been proposed to calculate the spatial-temporal distributions of temperature and resulting thermal stress in quartz particles during dynamic heating in polydisperse plasma flow.The influence of working gas compositions,particle size distributions,injection angle and flow rate of carrier gas on the thermal destruction conditions of quartz particles has been determined under different particle feed rates.It is found that all the solid quartz particles(0.1-0.4 mm)could be thermal destructed without overheating in RF-ICP torch system,when the hydrogen volume fraction in working gases is more than 1.5%-2%and particle feed rate is in a certain range.The values of the maximum and minimum feed rates have been determined under different hydrogen volume fractions.An optimal particle injection angle and flow rate of carrier gas is found around 50°-60°and 160-220 slpm,under which the value of maximum equivalent thermal stress in quartz particles is highest.
基金supported by National Natural Science Foundation of China(Nos.52202460,52177128)National Key R&D Program of China(Nos.2020YFC2201100,2021YFC2202804)+2 种基金China Postdoctoral Science Foundation(Nos.2021M690392,2021TQ0036)Science Foundation for Youth Scholars of the Beijing Institute of TechnologyAdvanced Space Propulsion Laboratory of BICE and the Beijing Engineering Research Centre of Efficient and Green Aerospace Propulsion Technology(No.LabASP-2021-04)。
文摘In the present work,the turbulent mixing process of a polydisperse quartz particle flow with a plasma stream generated by a radio-frequency(RF)inductively coupled plasma torch was numerically studied.The thermobaric stress in the quartz particles under dynamic heating in a heterogeneous plasma flow was determined by a two-stage approximation approach.The effect of the presence of vacuoles in natural quartz on the particle thermobaric destruction conditions was studied.It was found that the equivalent thermal and baric stresses in quartz particles may significantly increase in the presence of vacuoles within a small gas volume fraction.The influence of the regime and energetic working conditions of an RF inductively coupled plasma torch system on the particle thermobaric destruction conditions was examined,and a recommendation was given to promote the degree of thermobaric destruction of quartz particles,which is of substantial importance for improving the overall enrichment efficiency of quartz concentrates.
文摘THE Torch Festival is the most significant and grandest celebration for all Yi communities across China’s Yunnan,Guizhou,and Sichuan provinces,with a history spanning over a thousand years.It reflects the Yi people’s long-standing reverence for fire.Originating from the Yi ancestors’worship of fire,the festival was intended to drive away pests and evil spirits,protect crops,and represent prayers for a bountiful harvest.
文摘In this paper, a new MPT(microwave plasma torch) device has been used as a atomizer for atomic fluorescence spectrometry. Spme elements, such as Zn, Cd, Hg, Pb, As, Co, Mg, Cu, Ag, Mn, Fe have been investigated in detail.
基金supported by the National Science and Technology Major Project of China(No.HT-J2019-V-0023-0140)Open Project of State Key Laboratory of Advanced Special Steel,Shanghai Key Laboratory of Advanced Ferrometallurgy,Shanghai University(No.SKLASS 2023-03)the Science and Technology Commission of Shanghai Municipality(No.20511107700).
文摘A novel plasma torch nitriding technology was applied for the first time to improve the surface properties of M2 high-speed steel by adjusting different experimental parameters.The nitrogen content,precipitate,microstructure,mechanical property,and corrosion resistance of the nitrided layer were comprehensively analyzed using an ONH analyzer,scanning electron microscope(SEM),micro-area X-ray diffractometer,transmission electron microscope(TEM),Vickers microhardness tester,high-temperature wear tester,3D profilometer,tensile testing machine,and electrochemical workstation.The research results show that the novel plasma torch nitriding technology can achieve synergistic strengthening of nitrogen,carbon,and alloying element solid solution,precipitation strengthening,and martensitic structure on the surface of M2 high-speed steel.The nitrogen content on the specimen surface increased up to 0.17%,while the size and area of carbides were reduced by 89%and 86%,respectively,indicating a transformation towards fine nitrogen-rich precipitates.Compared to the original M2 steel,the nitrided specimens exhibited significant improvements in overall performance.The hardness increased from 228 HV_(0.2)to a maximum of 795 HV_(0.2),the wear coefficient decreased from a maximum of 0.8 to 0.49,the tensile strength increased from 753 MPa to a maximum of 934 MPa,and the corrosion current density decreased from 1.2×10^(−5)to a minimum of 1.9×10^(−6)A/cm^(2).
