COMFLEX-ML辅助连接设备中RTS(Rod Transfer System)烟支卸盘缓存装置存在滑板强度低、检测器误检率高、缺乏动力传递过载保护装置等缺陷,由此造成设备故障率高、停机时间长、维护成本高等问题。为此采用钢制滑板材料与大规格传感器对RT...COMFLEX-ML辅助连接设备中RTS(Rod Transfer System)烟支卸盘缓存装置存在滑板强度低、检测器误检率高、缺乏动力传递过载保护装置等缺陷,由此造成设备故障率高、停机时间长、维护成本高等问题。为此采用钢制滑板材料与大规格传感器对RTS烟支卸盘缓存装置进行了改进,并设计了动力传递过载保护装置。改进后RTS烟支卸盘缓存装置增强了滑板强度,增大了传感器的检测距离,过载保护装置在过载情况下可自动切断电机与缓存装置的动力传递,保证了装置的安全,平均故障次数由2.7次/月下降到0.5次/月,故障平均维护时间由168 min/次降低到12.7 min/次,减少了备件的损耗量,保证了设备的正常运行。展开更多
The single-phase heat transfer characteristics in a PWR fuel assembly are important. Many investigations attempt to obtain the heat transfer characteristics by studying the flow features in a 5 x 5 rod bundle with a s...The single-phase heat transfer characteristics in a PWR fuel assembly are important. Many investigations attempt to obtain the heat transfer characteristics by studying the flow features in a 5 x 5 rod bundle with a spacer grid. The field synergy principle is used to discuss the mechanism of heat transfer enhancement using mixing vanes according to computational fluid dynamics results, including a spacer grid without mixing vanes, one with a split mixing vane, and one with a separate mixing vane. The results show that the field synergy principle is feasible to explain the mechanism of heat transfer enhancement in a fuel assembly. The enhancement in subchannels is more effective than on the rod＇s surface. If the pressure loss is ignored, the performance of the split mixing vane is superior to the separate mixing vane based on the enhanced heat transfer. Increasing the blending angle of the split mixing vane improves heat transfer enhancement, the maximum of which is 7.1%. Increasing the blending angle of the separate mixing vane did not significantly enhance heat transfer in the rod btmdle, and even prevented heat transfer at a blending angle of 50%. This fmding testifies to the feasibility of predicting heat transfer in a rod bundle with a spacer grid by field synergy, and upon comparison with analyzed flow features only, the field synergy method may provide more accurate guidance for optimizing the use of mixing vanes.展开更多
The conventional heat exchanger with segmental baffles is prone to bring forth fluid-induced vibration of heat transfer tubes and increase the pressure drop of shell-side greatly at higher fluid flow velocity. In orde...The conventional heat exchanger with segmental baffles is prone to bring forth fluid-induced vibration of heat transfer tubes and increase the pressure drop of shell-side greatly at higher fluid flow velocity. In order to avoid the above defects, the ROD-baffle heat exchanger has been developed. However, its collocation of heat transfer tubes is conventionally in square, which leads to fewer heat transfer area per unit volume. Based on the ROD-baffle heat exchanger, a new type curve-ROD baffle has been developed, and an industrial investigation of the curve-ROD baffle heat exchanger with normal triangular collocation has been carried into execution. In this paper, two equations using the Reynolds number were acquired to predict the heat transfer coefficients of the shell-side and tube-side. The experimental results show that the shell-side heat transfer and pressure drop characteristics of the curve-ROD baffle heat exchanger are superior to those of the segmental baffle one.展开更多
An optically active rod coil rod triblock copolymer containing poly(ethylene oxide)(PEO) as the flexible segment and poly{(+) 2,5 bis[4′ ((s) 2 methyl butoxy) phenyl]styrene} (PMBPS) as the rigid segment,PMBPS b PEO ...An optically active rod coil rod triblock copolymer containing poly(ethylene oxide)(PEO) as the flexible segment and poly{(+) 2,5 bis[4′ ((s) 2 methyl butoxy) phenyl]styrene} (PMBPS) as the rigid segment,PMBPS b PEO b PMBPS,was synthesized via atom transfer radical polymerization.The PMBPS block had a stable helical conformation with an excess of screw sense in solution.The self assembly behavior of the triblock copolymer in dioxane/water mixed solvents was examined by means of TEM and turbidity measurements.The triblock copolymer molecules aggregated when water content in the system was about 2wt%. The higher the initial polymer concentrations,the lower the critical water content.They formed vesicles with highly dispersed outside diameters,but they had a relatively uniform wall thickness of (27±3) nm.展开更多
文摘COMFLEX-ML辅助连接设备中RTS(Rod Transfer System)烟支卸盘缓存装置存在滑板强度低、检测器误检率高、缺乏动力传递过载保护装置等缺陷,由此造成设备故障率高、停机时间长、维护成本高等问题。为此采用钢制滑板材料与大规格传感器对RTS烟支卸盘缓存装置进行了改进,并设计了动力传递过载保护装置。改进后RTS烟支卸盘缓存装置增强了滑板强度,增大了传感器的检测距离,过载保护装置在过载情况下可自动切断电机与缓存装置的动力传递,保证了装置的安全,平均故障次数由2.7次/月下降到0.5次/月,故障平均维护时间由168 min/次降低到12.7 min/次,减少了备件的损耗量,保证了设备的正常运行。
基金Supported by National Natural Science Foundation of China(Grant No.51376022)
文摘The single-phase heat transfer characteristics in a PWR fuel assembly are important. Many investigations attempt to obtain the heat transfer characteristics by studying the flow features in a 5 x 5 rod bundle with a spacer grid. The field synergy principle is used to discuss the mechanism of heat transfer enhancement using mixing vanes according to computational fluid dynamics results, including a spacer grid without mixing vanes, one with a split mixing vane, and one with a separate mixing vane. The results show that the field synergy principle is feasible to explain the mechanism of heat transfer enhancement in a fuel assembly. The enhancement in subchannels is more effective than on the rod＇s surface. If the pressure loss is ignored, the performance of the split mixing vane is superior to the separate mixing vane based on the enhanced heat transfer. Increasing the blending angle of the split mixing vane improves heat transfer enhancement, the maximum of which is 7.1%. Increasing the blending angle of the separate mixing vane did not significantly enhance heat transfer in the rod btmdle, and even prevented heat transfer at a blending angle of 50%. This fmding testifies to the feasibility of predicting heat transfer in a rod bundle with a spacer grid by field synergy, and upon comparison with analyzed flow features only, the field synergy method may provide more accurate guidance for optimizing the use of mixing vanes.
基金Project supported by the National Science Fund of Distinguished Young Scholars (No.10025211) the NJTU Paper Foundation (No.PD250) and the China Postdoctoral Science Foundation.
文摘The conventional heat exchanger with segmental baffles is prone to bring forth fluid-induced vibration of heat transfer tubes and increase the pressure drop of shell-side greatly at higher fluid flow velocity. In order to avoid the above defects, the ROD-baffle heat exchanger has been developed. However, its collocation of heat transfer tubes is conventionally in square, which leads to fewer heat transfer area per unit volume. Based on the ROD-baffle heat exchanger, a new type curve-ROD baffle has been developed, and an industrial investigation of the curve-ROD baffle heat exchanger with normal triangular collocation has been carried into execution. In this paper, two equations using the Reynolds number were acquired to predict the heat transfer coefficients of the shell-side and tube-side. The experimental results show that the shell-side heat transfer and pressure drop characteristics of the curve-ROD baffle heat exchanger are superior to those of the segmental baffle one.
文摘An optically active rod coil rod triblock copolymer containing poly(ethylene oxide)(PEO) as the flexible segment and poly{(+) 2,5 bis[4′ ((s) 2 methyl butoxy) phenyl]styrene} (PMBPS) as the rigid segment,PMBPS b PEO b PMBPS,was synthesized via atom transfer radical polymerization.The PMBPS block had a stable helical conformation with an excess of screw sense in solution.The self assembly behavior of the triblock copolymer in dioxane/water mixed solvents was examined by means of TEM and turbidity measurements.The triblock copolymer molecules aggregated when water content in the system was about 2wt%. The higher the initial polymer concentrations,the lower the critical water content.They formed vesicles with highly dispersed outside diameters,but they had a relatively uniform wall thickness of (27±3) nm.
