In this work,the effects of externally applied axial pressure gradients and transverse magnetic fields on the electrokinetic energy conversion(EKEC)efficiency and the streaming potential of nanofluids through a microa...In this work,the effects of externally applied axial pressure gradients and transverse magnetic fields on the electrokinetic energy conversion(EKEC)efficiency and the streaming potential of nanofluids through a microannulus are studied.The analytical solution for electro-magneto-hydro-dynamic(EMHD)flow is obtained under the condition of the Debye-Huuckel linearization.Especially,Green’s function method is used to obtain the analytical solutions of the velocity field.The result shows that the velocity distribution is characterized by the dimensionless frequency?,the Hartmann number Ha,the volume fraction of the nanoparticlesφ,the geometric radius ratio a,and the wallζpotential ratio b.Moreover,the effects of three kinds of periodic excitations are compared and discussed.The results also show that the periodic excitation of the square waveform is more effective in increasing the streaming potential and the EKEC efficiency.It is worth noting that adjusting the wallζpotential ratio and the geometric radius ratio can affect the streaming potential and the EKEC efficiency.展开更多
The hot deformation behavior of IN706 has been investigated by means of hot compression tests in the temperature range of 900-1150℃ and strain rate range of 0.001-1 s^-1. The constitutive equation was developed on th...The hot deformation behavior of IN706 has been investigated by means of hot compression tests in the temperature range of 900-1150℃ and strain rate range of 0.001-1 s^-1. The constitutive equation was developed on the basis of experimental data. Power dissipation efficiency （η） and instability parameter （4） maps were evaluated using the principles of the dynamic material model. Furthermore, the EBSD microstructure analysis was performed for validation, revealing that η was closely associated with the mechanism of dynamic recrystallization （DRX）. Microstructure transition map was composed of contour plots of η, 4, and DRX. The DRX domain zones and instable zones were identified in the processing map and were classified based on η. In a view of microstructure refinement and workability improvement, the optimum processing should be selected in the temperature range of 970-1025 ~C and the strain rate range of 0.08-0.01 s^-1.展开更多
Hot compression test was carried out at 1000 ~C to investigate the dynamic recrys- tallization nucleation mechanism of a nickel-base superalloy. It was found that the bulging of original grain boundaries was inhibited...Hot compression test was carried out at 1000 ~C to investigate the dynamic recrys- tallization nucleation mechanism of a nickel-base superalloy. It was found that the bulging of original grain boundaries was inhibited by carbides and deformation twins at the boundaries. Recrystallized nuclei evolved from the subgrains of dislocation re- configuration along original grain boundaries, and the growth of the potential nuclei was carried out by the coalescence of subgrains. The necklace structure of recrys- tallized grains along original grain boundaries was attributed to the strain gradient from grain boundary to grain interior.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.11772162,11802147)the Natural Science Foundation of Inner Mongolia(No.2018LH01015)+1 种基金the Foundation of Inner Mongolia Autonomous Region University Scientific Research Project(No.NJZY18093)the Foundation of Inner Mongolia University of Technology(No.ZD201714)。
文摘In this work,the effects of externally applied axial pressure gradients and transverse magnetic fields on the electrokinetic energy conversion(EKEC)efficiency and the streaming potential of nanofluids through a microannulus are studied.The analytical solution for electro-magneto-hydro-dynamic(EMHD)flow is obtained under the condition of the Debye-Huuckel linearization.Especially,Green’s function method is used to obtain the analytical solutions of the velocity field.The result shows that the velocity distribution is characterized by the dimensionless frequency?,the Hartmann number Ha,the volume fraction of the nanoparticlesφ,the geometric radius ratio a,and the wallζpotential ratio b.Moreover,the effects of three kinds of periodic excitations are compared and discussed.The results also show that the periodic excitation of the square waveform is more effective in increasing the streaming potential and the EKEC efficiency.It is worth noting that adjusting the wallζpotential ratio and the geometric radius ratio can affect the streaming potential and the EKEC efficiency.
基金financially supported by the High Technology Research and Development Program of China (No.SS2012AA030801)the National Basic Research Development Program of China (No.2010CB631203)the Common Technical Research Aircraft Key Component Forming (No.2012ZX04010-081)
文摘The hot deformation behavior of IN706 has been investigated by means of hot compression tests in the temperature range of 900-1150℃ and strain rate range of 0.001-1 s^-1. The constitutive equation was developed on the basis of experimental data. Power dissipation efficiency （η） and instability parameter （4） maps were evaluated using the principles of the dynamic material model. Furthermore, the EBSD microstructure analysis was performed for validation, revealing that η was closely associated with the mechanism of dynamic recrystallization （DRX）. Microstructure transition map was composed of contour plots of η, 4, and DRX. The DRX domain zones and instable zones were identified in the processing map and were classified based on η. In a view of microstructure refinement and workability improvement, the optimum processing should be selected in the temperature range of 970-1025 ~C and the strain rate range of 0.08-0.01 s^-1.
基金supported by the National Basic Research Program of China (No.2010CB631203)the National Natural Science Foundation of China (No.50841025)
文摘Hot compression test was carried out at 1000 ~C to investigate the dynamic recrys- tallization nucleation mechanism of a nickel-base superalloy. It was found that the bulging of original grain boundaries was inhibited by carbides and deformation twins at the boundaries. Recrystallized nuclei evolved from the subgrains of dislocation re- configuration along original grain boundaries, and the growth of the potential nuclei was carried out by the coalescence of subgrains. The necklace structure of recrys- tallized grains along original grain boundaries was attributed to the strain gradient from grain boundary to grain interior.
