Speaker
Youhua Chen
(University of Science and Technology of China)
Description
The neutron multiplier and the tritium breeder materials are made into millimeter-sized particles and arranged in the solid breeder blanket. Helium (mixed with 0.1% content of H2) is used as the purge gas to sweep tritium out when it flows through the pebble beds. Previous research shows that binary pebble beds present a better performance in tritium breeding than unitary pebble beds. Since the flow characteristics of helium in binary pebble beds are very important parameters for the evaluation of tritium sweep capability and the design of tritium recovery system, DEM-CFD method was induced in this paper to determine the flow characteristics. The distinct element method (DEM) was applied to produce a geometric topology of binary pebble beds by directly simulating the contact state of each individual particle using basic interaction laws. Based on the geometric topology, a computational fluid dynamics (CFD) model was built to analyze the flow characteristics including pressure drop, velocity field and so on. In the current study, pebble beds with different diameter ratios and different packing factors were simulated. It was found that the pressure drop of binary pebble bed increased greatly with the rise of the packing factor and was much larger than mono-sized pebble bed. Besides, strong nonuniformity of velocity distribution was observed from the velocity field and stagnation flow was more obvious than single-size pebble bed. This method can be well used to optimize the particle diameter ratio of a preferable binary pebble bed in order to obtain appropriate pressure drop and acceptable tritium sweep capability for the design of fusion blanket.
Co-authors
Lei Chen
(Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, China)
Songlin Liu
(Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, China)
Youhua Chen
(University of Science and Technology of China, Hefei, China;Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, China)
