A 3D-reconstruction Research On The Visual Liquid-pebble Bed

During the past few years,molten salt reactor,as one of the six candidates for the generation IV nuclear energy system,has withdrew a large amount of attention in the nuclear energy field.In pebble bed reactor,the packing factor plays a vital role in thermal hydraulic design as well as reactor core physical design.In current research phase,with the lack of specific technique to obtain the packing factor of pebble bed reactor core,a kind of 3D reconstruction based on computer vision and discrete element method in a visual pebble bed is a feasible way to obtain an accurate factor of packing.The dissertation aims at construction for a visual pebble bed,3D reconstruction based on computer vision and pebble expanding based on discrete element method,which includes:1)RIMS method was used to create a visual pebble bed which is equiped with 414 sphere pebbles which are all 3 cm in diameter.PMMA was chose to made up of pebbles because of its transparence and Na I was chose as matching liquid because of its nontoxic,and the matching refractive index is 1.49.2)Reconstruction based on computer vision method.Threshold transformation,Filter transformation as well as Huff transformation was performed to improve image quality,and several codes were written to create a reconstructive pebble bed in computer.3)Pebble expanding based on Discrete Element Method.An algorithm based on Discrete Element Method was applied to expand the pebbles in computer,in order to eliminating the overlap of the balls.And thanks to the algorithm,the 3D reconstruction shares a higher accuracy.