The slurry pump is the key component of a dredger. Solid particles have strong influence on the performance of a slurry pump. The movement of solid particles in a centrifugal impeller was studied using particle image ...The slurry pump is the key component of a dredger. Solid particles have strong influence on the performance of a slurry pump. The movement of solid particles in a centrifugal impeller was studied using particle image velocimetry(PIV) measurement. The experiments were conducted in a dredging pump model at Hohai University. Some transparent glass spheres with diameter of 0. 2-0. 4 mm were used as solid particles. The concentration and relative velocities of the particles were analyzed to investigate the particle trajectory. The results show that the concentration of the particles on the pressure surfaces of the blades is higher than on the suction surfaces,and the particles tend to move towards the suction surfaces. Moreover,the particles have faster relative velocities than the liquid phase through the flow channels of the impeller.展开更多
CHC Trailing suction hopper dredgers (TSHD) have been widely used in dredging industry. In order to simulate the dredging process accurately, a mathematical model for a swell compensator used in TSHD is proposed, and ...CHC Trailing suction hopper dredgers (TSHD) have been widely used in dredging industry. In order to simulate the dredging process accurately, a mathematical model for a swell compensator used in TSHD is proposed, and a friendly simulation model based on the Automated Dynamic Analysis of Mechanical Systems (ADAMS) is built to test and validate the mathematical model for the swell compensator. The factors influencing the dynamic behavior of the TSHD suction pipe system, such as the mo-tion of the vessel in an unquiet situation with different water current velocities, seabed profiles, seabed soil hardness and the forces acting on the suction pipe system, have been taken into consideration. The simulation results show that they fit in with the operat-ing practice qualitatively.展开更多
Using experimental values of the structure factor of liquid Se1-xTex(x =0. 0, 0. 6, 0. 7, 0. 8, 1. 0. ) alloys measured by Takeda et al., the potential functions at different compositions are derived from Rao-Joarder&...Using experimental values of the structure factor of liquid Se1-xTex(x =0. 0, 0. 6, 0. 7, 0. 8, 1. 0. ) alloys measured by Takeda et al., the potential functions at different compositions are derived from Rao-Joarder'S equation. From the change of the shape of the potential function at different compositions, we can infer that when x is between 0. 7 and 0. 8 the nonmetal-metal transition occurs in this system. This is the first time to use the calculation of the potential function to find the NM-M transition Furthermore we give the longitudinal and transverse phonon frequencies by using Bhatia-Singh'S model. Then the elastic constants are computed. Using the potential function, the characteristic frequency is obtained and compared with the average frequency, Debye frequency, and the maximum longitudinal frequency compute4 by other methods. Finally, we compare the sound velocities calculated from the elastic constants in the long-wave limit with corresponding experimental values.展开更多
A collocation method is employed to study the effective ac conductivity of a suspension of charged particles in electrolyte solution.The method is very effective over a wide range of particle concentration and no long...A collocation method is employed to study the effective ac conductivity of a suspension of charged particles in electrolyte solution.The method is very effective over a wide range of particle concentration and no longer restricted to the assumption made by the Rayleigh method that the two phases of a suspension have the same dielectric constants.展开更多
文摘The slurry pump is the key component of a dredger. Solid particles have strong influence on the performance of a slurry pump. The movement of solid particles in a centrifugal impeller was studied using particle image velocimetry(PIV) measurement. The experiments were conducted in a dredging pump model at Hohai University. Some transparent glass spheres with diameter of 0. 2-0. 4 mm were used as solid particles. The concentration and relative velocities of the particles were analyzed to investigate the particle trajectory. The results show that the concentration of the particles on the pressure surfaces of the blades is higher than on the suction surfaces,and the particles tend to move towards the suction surfaces. Moreover,the particles have faster relative velocities than the liquid phase through the flow channels of the impeller.
文摘CHC Trailing suction hopper dredgers (TSHD) have been widely used in dredging industry. In order to simulate the dredging process accurately, a mathematical model for a swell compensator used in TSHD is proposed, and a friendly simulation model based on the Automated Dynamic Analysis of Mechanical Systems (ADAMS) is built to test and validate the mathematical model for the swell compensator. The factors influencing the dynamic behavior of the TSHD suction pipe system, such as the mo-tion of the vessel in an unquiet situation with different water current velocities, seabed profiles, seabed soil hardness and the forces acting on the suction pipe system, have been taken into consideration. The simulation results show that they fit in with the operat-ing practice qualitatively.
文摘Using experimental values of the structure factor of liquid Se1-xTex(x =0. 0, 0. 6, 0. 7, 0. 8, 1. 0. ) alloys measured by Takeda et al., the potential functions at different compositions are derived from Rao-Joarder'S equation. From the change of the shape of the potential function at different compositions, we can infer that when x is between 0. 7 and 0. 8 the nonmetal-metal transition occurs in this system. This is the first time to use the calculation of the potential function to find the NM-M transition Furthermore we give the longitudinal and transverse phonon frequencies by using Bhatia-Singh'S model. Then the elastic constants are computed. Using the potential function, the characteristic frequency is obtained and compared with the average frequency, Debye frequency, and the maximum longitudinal frequency compute4 by other methods. Finally, we compare the sound velocities calculated from the elastic constants in the long-wave limit with corresponding experimental values.
基金Supported by the National Natural Science Foundation of China
文摘A collocation method is employed to study the effective ac conductivity of a suspension of charged particles in electrolyte solution.The method is very effective over a wide range of particle concentration and no longer restricted to the assumption made by the Rayleigh method that the two phases of a suspension have the same dielectric constants.
