The surface quality of fine-grained ZrO2 engineering ceramic were researched using 270# diamond wheel both with and without work-piece two-dimension ultrasonic vibration grinding（WTDUVG）. By AFM images, the surface ...The surface quality of fine-grained ZrO2 engineering ceramic were researched using 270# diamond wheel both with and without work-piece two-dimension ultrasonic vibration grinding（WTDUVG）. By AFM images, the surface topography and the micro structure of the two-dimensional ultrasonic vibration grinding ceramics were especially analyzed. The experimental results indicate that the surface roughness is related to grinding vibration mode and the material removal mechanism. Surface quality of WTDUVG is superior to that of conventional grinding, and it is easy for two-dimensional ultrasonic vibration grinding that material removal mechanism is ductile mode grinding.展开更多
The flow field or multidimensional velocity distribution of the coolant in fuel rod bundles of the reactor core in pressurized water reactors (PWRs) is an important parameter that is revealed through experimental inve...The flow field or multidimensional velocity distribution of the coolant in fuel rod bundles of the reactor core in pressurized water reactors (PWRs) is an important parameter that is revealed through experimental investigations. This paper presents the two-dimensional (2D) velocity profile measurement using a two-element ultrasonic transducer with both elements acting as a transceiver. The size of the transducer is minimized for compactness, leading to a narrow sound field appropriate for applications in fuel rod bundle flow. Furthermore, the transducer’s sound pressure is evaluated via simulations and experimental measurements. In order to confirm the ability of the ultrasonic velocity profiler (UVP) with a two-element transducer, the experimental measurement is conducted in turbulent horizontal pipe flow. The 2D velocity vector profile is obtained, and then the measurement in swirling flow is conducted. The 2D velocity profile in an axial and radial plane is obtained utilizing the UVP measurement. Lastly, the ability of the UVP to derive the 2D velocity profile in the narrow area of the rod bundles is demonstrated.展开更多
An experimental investigation was performed to investigate two-dimensional axial velocity field at downstream of the 90°double bend pipe with and without inlet swirling condition. The main objectives are to fi...An experimental investigation was performed to investigate two-dimensional axial velocity field at downstream of the 90°double bend pipe with and without inlet swirling condition. The main objectives are to find separation region and observe the influence of inlet swirling flow on the velocity fluctuation using ultrasound technique. The experiments were carried out in the pipe at Reynolds number Re = 1 × 104. In case of inlet swirling flow condition, a rotary swirler was used as swirling generator, and the swirl number was setup S = 1. The ultrasonic measurements were taken at four downstream locations of the second bend pipe. Phased Array Ultrasonic Velocity Profiler (Phased Array UVP) technique was applied to obtain the two-dimensional velocity of the fluid and the axial and tangential velocity fluctuation. It was found that the secondary reverse flow became smaller at the downstream from the bend when the inlet condition on the first bend was swirling flow. In addition, inlet swirling condition influenced mainly on the tangential velocity fluctuation, and its maximum turbulence intensity was 40%.展开更多
基金Funded by the Shanxi Province Science Foundation for Youths(2006021026)
文摘The surface quality of fine-grained ZrO2 engineering ceramic were researched using 270# diamond wheel both with and without work-piece two-dimension ultrasonic vibration grinding（WTDUVG）. By AFM images, the surface topography and the micro structure of the two-dimensional ultrasonic vibration grinding ceramics were especially analyzed. The experimental results indicate that the surface roughness is related to grinding vibration mode and the material removal mechanism. Surface quality of WTDUVG is superior to that of conventional grinding, and it is easy for two-dimensional ultrasonic vibration grinding that material removal mechanism is ductile mode grinding.
文摘The flow field or multidimensional velocity distribution of the coolant in fuel rod bundles of the reactor core in pressurized water reactors (PWRs) is an important parameter that is revealed through experimental investigations. This paper presents the two-dimensional (2D) velocity profile measurement using a two-element ultrasonic transducer with both elements acting as a transceiver. The size of the transducer is minimized for compactness, leading to a narrow sound field appropriate for applications in fuel rod bundle flow. Furthermore, the transducer’s sound pressure is evaluated via simulations and experimental measurements. In order to confirm the ability of the ultrasonic velocity profiler (UVP) with a two-element transducer, the experimental measurement is conducted in turbulent horizontal pipe flow. The 2D velocity vector profile is obtained, and then the measurement in swirling flow is conducted. The 2D velocity profile in an axial and radial plane is obtained utilizing the UVP measurement. Lastly, the ability of the UVP to derive the 2D velocity profile in the narrow area of the rod bundles is demonstrated.
文摘An experimental investigation was performed to investigate two-dimensional axial velocity field at downstream of the 90°double bend pipe with and without inlet swirling condition. The main objectives are to find separation region and observe the influence of inlet swirling flow on the velocity fluctuation using ultrasound technique. The experiments were carried out in the pipe at Reynolds number Re = 1 × 104. In case of inlet swirling flow condition, a rotary swirler was used as swirling generator, and the swirl number was setup S = 1. The ultrasonic measurements were taken at four downstream locations of the second bend pipe. Phased Array Ultrasonic Velocity Profiler (Phased Array UVP) technique was applied to obtain the two-dimensional velocity of the fluid and the axial and tangential velocity fluctuation. It was found that the secondary reverse flow became smaller at the downstream from the bend when the inlet condition on the first bend was swirling flow. In addition, inlet swirling condition influenced mainly on the tangential velocity fluctuation, and its maximum turbulence intensity was 40%.
