The phase separation in Ni75AlxV25-x alloys incorporated with the elastic stress was investigated using the microscopic phase-field model. The final morphology ofγ' andθis similar in spatial alignment, but the v...The phase separation in Ni75AlxV25-x alloys incorporated with the elastic stress was investigated using the microscopic phase-field model. The final morphology ofγ' andθis similar in spatial alignment, but the volume fraction ofγ' phase increases and that ofθdecreases as the Al concentration increases. For the small elastic interactions of early-stage phase separation, the coarsening ofγ' andθcan be approximated by a linear growth law as predicated by Lifshitz and Slyozov and Wangner (LSW) theory. As the elastic interactions increase at late-stage coarsening, the growth rate decreases, and the growth presents quick increase at early-stage and slows down at late-stage.展开更多
Based on the commercial CFD software CFX-4.3, two-phase flow of electrolyte in 156 kA drained aluminum reduction cells with a new structure was numerically simulated by multi-fluid model and k-ε turbulence model. The...Based on the commercial CFD software CFX-4.3, two-phase flow of electrolyte in 156 kA drained aluminum reduction cells with a new structure was numerically simulated by multi-fluid model and k-ε turbulence model. The results show that the electrolyte flow in the drained cells is more even than in the conventional cells. Corresponding to center point feeding, the electrolyte flow in the drained cells is more advantageous to the release of anode gas, the dissolution and diffusion of alumina, and the gradient reduction of the electrolyte density and temperature. The average velocity of the electrolyte is 8.3 cm/s, and the maximum velocity is 59.5 cm/s. The average and maximum velocities of the gas are 23.2 cm/s and 61.1 cm/s, respectively. The cathode drained slope and anode cathode distance have certain effects on the electrolyte flow.展开更多
Isothermal solidification process of a dissimilar transient liquid phase （TLP） bonding of FSX-414/MBF80/IN738 system was simulated by finite difference method. The TLP joint model was divided into two parts and a mo...Isothermal solidification process of a dissimilar transient liquid phase （TLP） bonding of FSX-414/MBF80/IN738 system was simulated by finite difference method. The TLP joint model was divided into two parts and a moving liquid /solid interface model was used for the parts. Diffusion equations were solved for each half of the joints simultaneously up to the end of isothermal solidification. The completion time of isothermal solidification, concentration profiles and position of the solid/liquid interface for each half were calculated. The intersection of the solid/liquid interfaces of two halves was considered the end of isothermal solidification. To obtain some required diffusion data, TLP bonding of FSX-414/MBF80/IN738 was performed at different temperature and time under vacuum atmosphere. The calculated results show good agreement with the experimental results.展开更多
Experiments were conducted to study characteristics of flow when flow is fluctuating.The experimental results showed a phase difference between the flow rate and the pressure drop fluctuations.This phase difference be...Experiments were conducted to study characteristics of flow when flow is fluctuating.The experimental results showed a phase difference between the flow rate and the pressure drop fluctuations.This phase difference between the fluctuating flow rate and pressure drop was analyzed for laminar flow.Analysis showed that the phase difference changes with the period of the flow fluctuation, the pipe radius, the density and the dynamic viscosity of the liquid.Fluctuating pipe flow was then numerically simulated.Results of the numerical simulation were compared with theoretical values and experimental results.It was shown that, when the flow rate fluctuates with time as a sine wave, the pressure drop fluctuates with the same periodicity, and there is a phase difference between them.展开更多
Nanoqueous phase liquid(NAPL) simulator is a powerful and popular mathematical model for modeling the flow and transport of non-aqueous phase liquids in subsurface,but the testing of its feasibility under water table ...Nanoqueous phase liquid(NAPL) simulator is a powerful and popular mathematical model for modeling the flow and transport of non-aqueous phase liquids in subsurface,but the testing of its feasibility under water table fluctuation has received insufficient attention.The feature in a column test was tested through two cycles of water table fluctuation.The sandy medium in the column was initially saturated,and each cycle of water table fluctuation consisted of one water table falling and one rising,resulting in a drainage and an imbibition of the medium,respectively.It was found that the difference between the simulated and measured results in the first drainage of the column test was minor.However,with the propagation of the water table fluctuations,the simulation errors increased,and the simulation accuracy was not acceptable except for the first drainage in the two fluctuation cycles.The main reason was proved to be the estimation method of residual saturation used in this simulator.Also,based on the column tests,it was assumed that the resulting residual saturation from an incomplete imbibition process was a constant,with a value equal to that of the residual value resulting from the main imbibition process.The results obtained after modifying NAPL simulator with this assumption were found to be more accurate in the first cycle of water table fluctuation,but this accuracy decreased rapidly in the second one.It is concluded that NAPL simulator is not adequate in the case of LNAPL migration under water table fluctuation in sandy medium,unless a feasible assumption to estimate residual saturation is put forward.展开更多
A comprehensive simulation was performed to better understand the impacts and effects of the additional technical noises on weak-light phase-locking for LISA. The result showed that the phase of the slave laser tracke...A comprehensive simulation was performed to better understand the impacts and effects of the additional technical noises on weak-light phase-locking for LISA. The result showed that the phase of the slave laser tracked well with the received transmitting light under different noise level, and the locking precision was limited by the phase readout noise when the laser frequency noise and clock jitter noise were removed. This result was then confirmed by a benchtop experimental test. The required LISA noise floor was recovered from the simulation which proved the validity of the simulation program. In order to convert the noise function into real time data with random characteristics, an algorism based on Fourier transform was also invented.展开更多
基金Project (50071046) supported by the National Natural Science Foundation of ChinaProject (2002AA331051)supported by the National Hi-Tech Research and Development Program of ChinaProject(CX200507) supported by the the Doctorate Foundation of Northwestern Polytechnical University
文摘The phase separation in Ni75AlxV25-x alloys incorporated with the elastic stress was investigated using the microscopic phase-field model. The final morphology ofγ' andθis similar in spatial alignment, but the volume fraction ofγ' phase increases and that ofθdecreases as the Al concentration increases. For the small elastic interactions of early-stage phase separation, the coarsening ofγ' andθcan be approximated by a linear growth law as predicated by Lifshitz and Slyozov and Wangner (LSW) theory. As the elastic interactions increase at late-stage coarsening, the growth rate decreases, and the growth presents quick increase at early-stage and slows down at late-stage.
基金Project(G1999064903) supported by the National Key Fundamental Research and Development Program of China
文摘Based on the commercial CFD software CFX-4.3, two-phase flow of electrolyte in 156 kA drained aluminum reduction cells with a new structure was numerically simulated by multi-fluid model and k-ε turbulence model. The results show that the electrolyte flow in the drained cells is more even than in the conventional cells. Corresponding to center point feeding, the electrolyte flow in the drained cells is more advantageous to the release of anode gas, the dissolution and diffusion of alumina, and the gradient reduction of the electrolyte density and temperature. The average velocity of the electrolyte is 8.3 cm/s, and the maximum velocity is 59.5 cm/s. The average and maximum velocities of the gas are 23.2 cm/s and 61.1 cm/s, respectively. The cathode drained slope and anode cathode distance have certain effects on the electrolyte flow.
文摘Isothermal solidification process of a dissimilar transient liquid phase （TLP） bonding of FSX-414/MBF80/IN738 system was simulated by finite difference method. The TLP joint model was divided into two parts and a moving liquid /solid interface model was used for the parts. Diffusion equations were solved for each half of the joints simultaneously up to the end of isothermal solidification. The completion time of isothermal solidification, concentration profiles and position of the solid/liquid interface for each half were calculated. The intersection of the solid/liquid interfaces of two halves was considered the end of isothermal solidification. To obtain some required diffusion data, TLP bonding of FSX-414/MBF80/IN738 was performed at different temperature and time under vacuum atmosphere. The calculated results show good agreement with the experimental results.
基金Supported by the National Natural Science Foundation of China under Grant No.50806014the Foundation of Bubble Physics and Natural Circulation Laboratory of China under Grant No.51482010105CB0101 and No.9140C7105020805
文摘Experiments were conducted to study characteristics of flow when flow is fluctuating.The experimental results showed a phase difference between the flow rate and the pressure drop fluctuations.This phase difference between the fluctuating flow rate and pressure drop was analyzed for laminar flow.Analysis showed that the phase difference changes with the period of the flow fluctuation, the pipe radius, the density and the dynamic viscosity of the liquid.Fluctuating pipe flow was then numerically simulated.Results of the numerical simulation were compared with theoretical values and experimental results.It was shown that, when the flow rate fluctuates with time as a sine wave, the pressure drop fluctuates with the same periodicity, and there is a phase difference between them.
基金Project(41072182)supported by the National Natural Science Foundation of ChinaProject(2010Z1-E101)supported by Science and Technology Program of Guangzhou City,China+1 种基金Project(20100103)supported by Science and Technology Program of Daya Bay,Huizhou City,ChinaProject(2012A030700008)supported by the Science and Technology Planning Program of Guangdong Province,China
文摘Nanoqueous phase liquid(NAPL) simulator is a powerful and popular mathematical model for modeling the flow and transport of non-aqueous phase liquids in subsurface,but the testing of its feasibility under water table fluctuation has received insufficient attention.The feature in a column test was tested through two cycles of water table fluctuation.The sandy medium in the column was initially saturated,and each cycle of water table fluctuation consisted of one water table falling and one rising,resulting in a drainage and an imbibition of the medium,respectively.It was found that the difference between the simulated and measured results in the first drainage of the column test was minor.However,with the propagation of the water table fluctuations,the simulation errors increased,and the simulation accuracy was not acceptable except for the first drainage in the two fluctuation cycles.The main reason was proved to be the estimation method of residual saturation used in this simulator.Also,based on the column tests,it was assumed that the resulting residual saturation from an incomplete imbibition process was a constant,with a value equal to that of the residual value resulting from the main imbibition process.The results obtained after modifying NAPL simulator with this assumption were found to be more accurate in the first cycle of water table fluctuation,but this accuracy decreased rapidly in the second one.It is concluded that NAPL simulator is not adequate in the case of LNAPL migration under water table fluctuation in sandy medium,unless a feasible assumption to estimate residual saturation is put forward.
基金supported by the Space Science Research Projects in Advance(Grant No.O930143XM1)the Scientific Equipment Development and Research Project(Grant No.Y231411YB1) of Chinese Academy of Sciences
文摘A comprehensive simulation was performed to better understand the impacts and effects of the additional technical noises on weak-light phase-locking for LISA. The result showed that the phase of the slave laser tracked well with the received transmitting light under different noise level, and the locking precision was limited by the phase readout noise when the laser frequency noise and clock jitter noise were removed. This result was then confirmed by a benchtop experimental test. The required LISA noise floor was recovered from the simulation which proved the validity of the simulation program. In order to convert the noise function into real time data with random characteristics, an algorism based on Fourier transform was also invented.
