Numerical and experimental investigation results on the magnetohydrodynamics（MHD） film flows along flat and curved bottom surfaces are summarized in this study. A simplified modeling has been developed to study the ...Numerical and experimental investigation results on the magnetohydrodynamics（MHD） film flows along flat and curved bottom surfaces are summarized in this study. A simplified modeling has been developed to study the liquid metal MHD film state, which has been validated by the existing experimental results. Numerical results on how the inlet velocity（V）, the chute width（W） and the inlet film thickness（d0） affect the MHD film flow state are obtained. MHD stability analysis results are also provided in this study. The results show that strong magnetic fields make the stable V decrease several times compared to the case with no magnetic field,especially small radial magnetic fields（Bn） will have a significant impact on the MHD film flow state. Based on the above numerical and MHD stability analysis results flow control methods are proposed for flat and curved MHD film flows. For curved film flow we firstly proposed a new multi-layers MHD film flow system with a solid metal mesh to get the stable MHD film flows along the curved bottom surface. Experiments on flat and curved MHD film flows are also carried out and some firstly observed results are achieved.展开更多
The integrity and reliability of fuel rods under both normal and accidental operating conditions are of great importance for nuclear reactors.In this study,considering various irradiation behaviors,a fuel rod performa...The integrity and reliability of fuel rods under both normal and accidental operating conditions are of great importance for nuclear reactors.In this study,considering various irradiation behaviors,a fuel rod performance analysis code,named KMC-Fueltra,was developed to evaluate the thermal–mechanical performance of oxide fuel rods under both normal and transient conditions in the LMFR.The accuracy and reliability of the KMC-Fueltra were validated by analytical solutions,as well as the results obtained from codes and experiments.The results indicated that KMC-Fueltra can predict the performance of oxide fuel rods under both normal and transient conditions in the LMFR.展开更多
In nuclear reactors cooled by liquid metals, ultrasound is the only type of field that allows obtaining images of the reactor cores and diagnostics of the integrity of the fuel assemblies. The article discusses the fe...In nuclear reactors cooled by liquid metals, ultrasound is the only type of field that allows obtaining images of the reactor cores and diagnostics of the integrity of the fuel assemblies. The article discusses the features of the practical realization of ultrasonic imaging systems based on phased arrays and offers an alternative solution of imaging on the basis of the acoustic lenses of refractive and diffraction types. Using lenses eliminates many of the technical and technological problems associated with the development of multi-element phased arrays. It is shown that lens systems allow using traditional methods of transformation of acoustic fields into the visible images by 2D piezo matrix and a more promising way of acoustooptical transformation based on coherent optical interferometry.展开更多
Various sources of solid particles might exist in the coolant flow of a liquid metal cooled fast reactor(e.g.,through chemical interaction between the coolant and impurities,air,or water,through corrosion of structura...Various sources of solid particles might exist in the coolant flow of a liquid metal cooled fast reactor(e.g.,through chemical interaction between the coolant and impurities,air,or water,through corrosion of structural materials,or from damaged/molten fuel).Such particles may cause flow blockage accidents in a fuel assembly,resulting in a reduction in coolant flow,which potentially causes a local temperature rise in the fuel cladding,cladding failure,and fuel melt.To understand the blockage formation mechanism,in this study,a series of simulated experiments was conducted by releasing different solid particles from a release device into a reducer pipe using gravity.Through detailed analyses,the influence of various experimental parameters(e.g.,particle diameter,capacity,shape,and static friction coefficient,and the diameter and height of the particle release nozzle)on the blockage characteristics(i.e.,blockage probability and position)was examined.Under the current range of experimental conditions,the blockage was significantly influenced by the aforementioned parameters.The ratio between the particle diameter and outlet size of the reducer pipe might be one of the determining factors governing the occurrence of blockage.Specifically,increasing the ratio enhanced blockage(i.e.,larger probability and higher position within the reducer pipe).Increasing the particle size,particle capacity,particle static friction coefficient,and particle release nozzle diameter led to a rise in the blockage probability;however,increasing the particle release nozzle height had a downward influence on the blockage probability.Finally,blockage was more likely to occur in non-spherical particles case than that of spherical particles.This study provides a large experimental database to promote an understanding of the flow blockage mechanism and improve the validation process of fast reactor safety analysis codes.展开更多
螺旋管蒸汽发生器是液态金属快堆中能量传递的核心设备,其运行的稳定性、安全性对核电站的运行有至关重要的影响。为此,本文构建了液态金属快堆螺旋管蒸汽发生器一次侧、二次侧耦合传热的三维数值模型,分别基于经济合作与发展组织核能署...螺旋管蒸汽发生器是液态金属快堆中能量传递的核心设备,其运行的稳定性、安全性对核电站的运行有至关重要的影响。为此,本文构建了液态金属快堆螺旋管蒸汽发生器一次侧、二次侧耦合传热的三维数值模型,分别基于经济合作与发展组织核能署(The Organisation for Economic Co-operation and Development,OECD/NEA)物性手册和美国国家标准与技术研究院(National Institute of Standards and Technology,NIST)数据库建立液态金属和水-水蒸气变物性计算关联式,采用Lee相变模型计算二次侧水-水蒸气蒸发过程中两相间的质量传递。基于实验数据,分别对本文模型一次侧传热以及二次侧传热的计算可靠性进行了验证。最后以铅铋快堆为例,研究了不同一次侧进口参数下蒸汽发生器一、二次侧之间的耦合传热特性,并与传统水冷堆进行了对比。结果表明:在同等条件下,相比于传统水冷堆,一次侧采用铅铋液态金属时,一、二次侧之间的壁面热流密度明显提升,热流密度峰值可达1439.97 kW·m^(-2),比水冷堆相应数值提升5~6倍,这导致二次侧管内气相蒸发过程明显加剧,体积含气率急剧上升;同时,一、二次侧之间的沿程热流密度分布更加不均匀,沿程热流密度分布相对偏差值比水冷堆相应数值增大3~4倍。随着一次侧进口铅铋温度从350℃增大到450℃,一、二次侧之间的壁面热流密度随之增大,对应的热流密度峰值从950.7 kW·m^(-2)增大到1439.97 kW·m^(-2),提升约1.5倍,同时一、二次侧之间的沿程热流密度分布更加不均匀,不均匀度增大20%。展开更多
基金supported by the National Magnetic Confinement Fusion Science Program of China(Nos.2014GB125003 and 2013GB114002)National Natural Science Foundation of China(No.11105044)
文摘Numerical and experimental investigation results on the magnetohydrodynamics（MHD） film flows along flat and curved bottom surfaces are summarized in this study. A simplified modeling has been developed to study the liquid metal MHD film state, which has been validated by the existing experimental results. Numerical results on how the inlet velocity（V）, the chute width（W） and the inlet film thickness（d0） affect the MHD film flow state are obtained. MHD stability analysis results are also provided in this study. The results show that strong magnetic fields make the stable V decrease several times compared to the case with no magnetic field,especially small radial magnetic fields（Bn） will have a significant impact on the MHD film flow state. Based on the above numerical and MHD stability analysis results flow control methods are proposed for flat and curved MHD film flows. For curved film flow we firstly proposed a new multi-layers MHD film flow system with a solid metal mesh to get the stable MHD film flows along the curved bottom surface. Experiments on flat and curved MHD film flows are also carried out and some firstly observed results are achieved.
文摘The integrity and reliability of fuel rods under both normal and accidental operating conditions are of great importance for nuclear reactors.In this study,considering various irradiation behaviors,a fuel rod performance analysis code,named KMC-Fueltra,was developed to evaluate the thermal–mechanical performance of oxide fuel rods under both normal and transient conditions in the LMFR.The accuracy and reliability of the KMC-Fueltra were validated by analytical solutions,as well as the results obtained from codes and experiments.The results indicated that KMC-Fueltra can predict the performance of oxide fuel rods under both normal and transient conditions in the LMFR.
文摘In nuclear reactors cooled by liquid metals, ultrasound is the only type of field that allows obtaining images of the reactor cores and diagnostics of the integrity of the fuel assemblies. The article discusses the features of the practical realization of ultrasonic imaging systems based on phased arrays and offers an alternative solution of imaging on the basis of the acoustic lenses of refractive and diffraction types. Using lenses eliminates many of the technical and technological problems associated with the development of multi-element phased arrays. It is shown that lens systems allow using traditional methods of transformation of acoustic fields into the visible images by 2D piezo matrix and a more promising way of acoustooptical transformation based on coherent optical interferometry.
基金supported by the Basic and Applied Basic Research Foundation of Guangdong Province(Nos.2021A1515010343,2022A1515011582)the Science and Technology Program of Guangdong Province(Nos.2021A0505030026,2022A0505050029).
文摘Various sources of solid particles might exist in the coolant flow of a liquid metal cooled fast reactor(e.g.,through chemical interaction between the coolant and impurities,air,or water,through corrosion of structural materials,or from damaged/molten fuel).Such particles may cause flow blockage accidents in a fuel assembly,resulting in a reduction in coolant flow,which potentially causes a local temperature rise in the fuel cladding,cladding failure,and fuel melt.To understand the blockage formation mechanism,in this study,a series of simulated experiments was conducted by releasing different solid particles from a release device into a reducer pipe using gravity.Through detailed analyses,the influence of various experimental parameters(e.g.,particle diameter,capacity,shape,and static friction coefficient,and the diameter and height of the particle release nozzle)on the blockage characteristics(i.e.,blockage probability and position)was examined.Under the current range of experimental conditions,the blockage was significantly influenced by the aforementioned parameters.The ratio between the particle diameter and outlet size of the reducer pipe might be one of the determining factors governing the occurrence of blockage.Specifically,increasing the ratio enhanced blockage(i.e.,larger probability and higher position within the reducer pipe).Increasing the particle size,particle capacity,particle static friction coefficient,and particle release nozzle diameter led to a rise in the blockage probability;however,increasing the particle release nozzle height had a downward influence on the blockage probability.Finally,blockage was more likely to occur in non-spherical particles case than that of spherical particles.This study provides a large experimental database to promote an understanding of the flow blockage mechanism and improve the validation process of fast reactor safety analysis codes.
文摘螺旋管蒸汽发生器是液态金属快堆中能量传递的核心设备,其运行的稳定性、安全性对核电站的运行有至关重要的影响。为此,本文构建了液态金属快堆螺旋管蒸汽发生器一次侧、二次侧耦合传热的三维数值模型,分别基于经济合作与发展组织核能署(The Organisation for Economic Co-operation and Development,OECD/NEA)物性手册和美国国家标准与技术研究院(National Institute of Standards and Technology,NIST)数据库建立液态金属和水-水蒸气变物性计算关联式,采用Lee相变模型计算二次侧水-水蒸气蒸发过程中两相间的质量传递。基于实验数据,分别对本文模型一次侧传热以及二次侧传热的计算可靠性进行了验证。最后以铅铋快堆为例,研究了不同一次侧进口参数下蒸汽发生器一、二次侧之间的耦合传热特性,并与传统水冷堆进行了对比。结果表明:在同等条件下,相比于传统水冷堆,一次侧采用铅铋液态金属时,一、二次侧之间的壁面热流密度明显提升,热流密度峰值可达1439.97 kW·m^(-2),比水冷堆相应数值提升5~6倍,这导致二次侧管内气相蒸发过程明显加剧,体积含气率急剧上升;同时,一、二次侧之间的沿程热流密度分布更加不均匀,沿程热流密度分布相对偏差值比水冷堆相应数值增大3~4倍。随着一次侧进口铅铋温度从350℃增大到450℃,一、二次侧之间的壁面热流密度随之增大,对应的热流密度峰值从950.7 kW·m^(-2)增大到1439.97 kW·m^(-2),提升约1.5倍,同时一、二次侧之间的沿程热流密度分布更加不均匀,不均匀度增大20%。
