基于重构的修正过程(correction procedure via reconstruction,CPR)方法是一种适用于非结构网格、紧致高效的高阶方法,但在离散非线性对流项时容易因为混淆误差的累积而出现数值不稳定。本文研究了基于LG(Legendre-Gauss)点分裂形式的...基于重构的修正过程(correction procedure via reconstruction,CPR)方法是一种适用于非结构网格、紧致高效的高阶方法,但在离散非线性对流项时容易因为混淆误差的累积而出现数值不稳定。本文研究了基于LG(Legendre-Gauss)点分裂形式的CPR方法在欠解析流动中的稳定性,并将其与子单元限制技术结合,求解含激波的欠解析流动问题。结果表明:经过边界通量修正的LG点分裂形式CPR格式能够满足离散守恒律,且与子单元限制相结合后守恒律依然成立;在无激波的欠解析流动问题中,相比于散度形式CPR格式,分裂形式明显提高了计算的稳定性,而且比使用LGL(Legendre-Gauss-Lobatto)点的分裂形式CPR格式具有更小的数值误差;在含激波的欠解析流动求解中,相比基于LGL点的间断伽辽金谱元法子单元限制策略,基于LG点的分裂形式CPR格式子单元限制策略具有更高的分辨率和更小的振荡。展开更多
Since the Fukushima accident in 2011,more and more attention has been paid to nuclear reactor safety.A number of evolutionary passive systems have been developed to enhance the inherent safety of reactors.This paper p...Since the Fukushima accident in 2011,more and more attention has been paid to nuclear reactor safety.A number of evolutionary passive systems have been developed to enhance the inherent safety of reactors.This paper presents a passive safety system applied on CPR1000,which is a traditional generation II+ reactor.The passive components selected are as follows:(1) the reactor makeup tanks(RMTs);(2) the advanced accumulators(A-ACCs);(3) the passive emergency feedwater system(PEFS);(4)the passive depressurization system(PDS);(5) the incontainment refueling water storage tank(IRWST).The model of the coolant system and the passive systems was established by utilizing a system code(RELAP5/MOD3.3).The SBLOCA(small-break loss of coolant) was analyzed to test the passive safety systems.When the SBLOCA occurred,the RMTs were initiated.The water in the RMTs was then injected into the pressure vessel.The RMTs' low water level triggered the PDS,which depressurized the coolant system drastically.As the pressure of the coolant system decreased,the A-ACCs and the IRWST were put to work to prevent the uncovering of the core.The results show that,after the small-break loss-of-coolant accident,the passive systems can prevent uncovering of the core and guarantee the safety of the plant.展开更多
重构修正(correction procedure via reconstruction, CPR)是一种计算高效、模板紧致、适用于非结构网格的高阶方法,但是无法处理流场含有较强间断的问题。针对这个问题,前期基于二阶非等距非线性加权插值的激波捕捉格式以及非结构四边...重构修正(correction procedure via reconstruction, CPR)是一种计算高效、模板紧致、适用于非结构网格的高阶方法,但是无法处理流场含有较强间断的问题。针对这个问题,前期基于二阶非等距非线性加权插值的激波捕捉格式以及非结构四边形网格,发展了高阶CPR方法的一种子单元限制技术。该技术首先通过侦测因子确定出问题单元,然后将问题单元基于CPR求解点划分成非等距子单元,并在子单元中采用二阶激波捕捉格式进行计算。这种子单元限制技术保证了主单元和子单元的求解点重合,可以十分方便地处理主单元和子单元之间的数据交换。问题单元的侦测是该子单元限制技术的关键步骤,侦测出的问题单元的数量以及分布情况都将会影响数值结果。基于此,本文同时考虑了单元侦测和分维侦测两种问题单元侦测方式。通过激波管问题、Shu-Osher问题、双马赫反射问题、激波-旋涡干扰等典型算例对比分析了TVB、MDHE和JST侦测因子对数值格式分辨率的影响。研究结果表明:分维侦测能够减少问题单元的区域,进而提高分辨率。展开更多
In order to solve problems associated with high heat production,high-energy consumption and low efficiency for the hydraulic system of the working device in a wrecker truck,a hydraulic energysaving system based on com...In order to solve problems associated with high heat production,high-energy consumption and low efficiency for the hydraulic system of the working device in a wrecker truck,a hydraulic energysaving system based on common pressure rail( CPR) is proposed. A hydraulic transformer is utilized to control the actuators by analyzing energy-consumption characteristics of valve controlled hydraulic system in a wrecker truck. By analyzing the energy-saving principle of a hydraulic energy-saving system,a relevant mathematical model is established. A comparison is performed between the energysaving hydraulic system and valve controlled hydraulic system in a wrecker truck within the same work period for operating efficiency and energy consumption. Results show that hydraulic energysaving system of the wrecker truck has better controlling performance and efficiency of about 18%higher than the valve controlled hydraulic system. Energy-saving ratio for total energy consumption in this system reaches 51. 46%,demonstrating energy-saving effect of the system.展开更多
文摘基于重构的修正过程(correction procedure via reconstruction,CPR)方法是一种适用于非结构网格、紧致高效的高阶方法,但在离散非线性对流项时容易因为混淆误差的累积而出现数值不稳定。本文研究了基于LG(Legendre-Gauss)点分裂形式的CPR方法在欠解析流动中的稳定性,并将其与子单元限制技术结合,求解含激波的欠解析流动问题。结果表明:经过边界通量修正的LG点分裂形式CPR格式能够满足离散守恒律,且与子单元限制相结合后守恒律依然成立;在无激波的欠解析流动问题中,相比于散度形式CPR格式,分裂形式明显提高了计算的稳定性,而且比使用LGL(Legendre-Gauss-Lobatto)点的分裂形式CPR格式具有更小的数值误差;在含激波的欠解析流动求解中,相比基于LGL点的间断伽辽金谱元法子单元限制策略,基于LG点的分裂形式CPR格式子单元限制策略具有更高的分辨率和更小的振荡。
基金supported by the National High-tech R&D Program of China(No.2012AA050905)
文摘Since the Fukushima accident in 2011,more and more attention has been paid to nuclear reactor safety.A number of evolutionary passive systems have been developed to enhance the inherent safety of reactors.This paper presents a passive safety system applied on CPR1000,which is a traditional generation II+ reactor.The passive components selected are as follows:(1) the reactor makeup tanks(RMTs);(2) the advanced accumulators(A-ACCs);(3) the passive emergency feedwater system(PEFS);(4)the passive depressurization system(PDS);(5) the incontainment refueling water storage tank(IRWST).The model of the coolant system and the passive systems was established by utilizing a system code(RELAP5/MOD3.3).The SBLOCA(small-break loss of coolant) was analyzed to test the passive safety systems.When the SBLOCA occurred,the RMTs were initiated.The water in the RMTs was then injected into the pressure vessel.The RMTs' low water level triggered the PDS,which depressurized the coolant system drastically.As the pressure of the coolant system decreased,the A-ACCs and the IRWST were put to work to prevent the uncovering of the core.The results show that,after the small-break loss-of-coolant accident,the passive systems can prevent uncovering of the core and guarantee the safety of the plant.
文摘重构修正(correction procedure via reconstruction, CPR)是一种计算高效、模板紧致、适用于非结构网格的高阶方法,但是无法处理流场含有较强间断的问题。针对这个问题,前期基于二阶非等距非线性加权插值的激波捕捉格式以及非结构四边形网格,发展了高阶CPR方法的一种子单元限制技术。该技术首先通过侦测因子确定出问题单元,然后将问题单元基于CPR求解点划分成非等距子单元,并在子单元中采用二阶激波捕捉格式进行计算。这种子单元限制技术保证了主单元和子单元的求解点重合,可以十分方便地处理主单元和子单元之间的数据交换。问题单元的侦测是该子单元限制技术的关键步骤,侦测出的问题单元的数量以及分布情况都将会影响数值结果。基于此,本文同时考虑了单元侦测和分维侦测两种问题单元侦测方式。通过激波管问题、Shu-Osher问题、双马赫反射问题、激波-旋涡干扰等典型算例对比分析了TVB、MDHE和JST侦测因子对数值格式分辨率的影响。研究结果表明:分维侦测能够减少问题单元的区域,进而提高分辨率。
基金Supported by the National Natural Science Foundation of China(No.51505289)Scientific Research Projects of Army(No.2014ZJ16,QT0703)
文摘In order to solve problems associated with high heat production,high-energy consumption and low efficiency for the hydraulic system of the working device in a wrecker truck,a hydraulic energysaving system based on common pressure rail( CPR) is proposed. A hydraulic transformer is utilized to control the actuators by analyzing energy-consumption characteristics of valve controlled hydraulic system in a wrecker truck. By analyzing the energy-saving principle of a hydraulic energy-saving system,a relevant mathematical model is established. A comparison is performed between the energysaving hydraulic system and valve controlled hydraulic system in a wrecker truck within the same work period for operating efficiency and energy consumption. Results show that hydraulic energysaving system of the wrecker truck has better controlling performance and efficiency of about 18%higher than the valve controlled hydraulic system. Energy-saving ratio for total energy consumption in this system reaches 51. 46%,demonstrating energy-saving effect of the system.
