Study On MHD Flow,Heat Transfer And Tritium Transport Of Complex Components For Liquid Metal Blanket

The fusion blanket structure is relatively complex for the adaption of the shape of plasma.Some geometery configurations are existed commonly for the liquid LiPb blanket,such as 3D sudden contract/expansion,bending channel and manifold.The 3D MHD effect with different flow characteristics happens in these different configurations.It is the most serious MHD issue appeared in the liquid metel blanket and also the commom issue for the design of the thermal hydraulics.Several key technical issues about liquid LiPb blanket were studied,including the multi-physics coupling code development,GPU acceleration,MHD flow and heat transfer characteristics anslysis and tritium transport parametric anslysis.Liquid lithium lead flow under fusion environment is complex and affected by multiple physics such as magnetohydrodynamic(MHD)flow.Based on the OpenFOAM platform,the multi-physical-MHDsolver was developed by using Multi-grid single matrix and double boundary coupling methods.Code validations were carried out for theoretical verification,numerical verification and experimental verification,such as Shercliff and Hunt’s case,KIT experiment case and TREX-MAN experiment data,etc.Good validation results were achieved.Two GPU acceleration methods were developed including GPU heterogeneous and full GPU acceleration.For the CPU parallel performance analysis,solving algorithm is the main factor to solve the MHD flow and parallel block has an oberviously effect on the parallel efficiency.CPU and GPU solver were based on the same case to analyze different parameters effect including common fluid,MHD fluid,different algorithm and grid sizes.The results showed that the GPU is suitable for solving MHD problems and accelerating significantly on large grid problems.The MHD flow and heat transfer analysis in the complex geometrical structures existing in the liquid lithium lead cladding are described.The characteristics of the complex geometrical elements are collectively classified.The numerical simulation analysis of the MHD flow of the complex geometric flow path,such as elbow,distribution header and pipe wall with helium channel,is carried out.Based on the pipeline MHD flow,the heat transfer coupling characteristic is analyzed and compared.Parametric studies are performed to quantify the velocity effects,MHD effects,wall conductivity effects,and the uncertainties of transport properties.The MHD effects reduce the tritium permeation rate due to the higher velocity near the wall.However,the rate of decrease is reduced at higher Hartmann numbers.The range of permeation rate change on the basis of uncertainties of transport properties is also provided,and the effect of the uncertainty of tritium solubility is significant.The study will not only have a significant role on the design optimization of the blanket structure and thermal hydraulics,but also enrich the flow and heat transfer theories about the MHD effect and tritium transport in the liquid metel blanket.