Heat Transfer Behavior And Design Of Granular Flow Target

Target facility is a kind of general purpose research device. The improving requirement of experimental condition demands for high power endurance of target. This dissertation studied the heat transfer behavior and design of a new type target with the background of accelerator driven system(ADS).Using granules as target material, heat deposit in this target is continuously removed by the gravity-driven dense granular flow. Compare to previous liquid metal target, researches showed improvements in the aspects of temperature endurance, material feasibility, and systematical reliability, which leads to promising potential of high power situation.The heat transfer properties plays important role in the usage of granular material as target material. Heat transfer in granular material performs in complicated ways, which will be reviewed in the 2nd chapter. The factors which affect the granular heat transfer were discussed, so were the estimation method.Different from the operation experience of liquid metal target, granular material as heat transfer medium in target facility is principally feasible, but still needs more detailed work. One of these aspects is heat effect under the specific structure, which is discussed in this dissertation based on the original research work. The research of this issue should rely on not only individual numerical research, but more of facility build up and experimental verification. Therefore, this dissertation researched a specific type of dense granular flow target for ADS system numerically and experimentally. Characteristics of were compared with a well-studied windowless liquid metal target. As a report of original work during doctor, the 3rd to 5th chapter respectively set forth the key issue of heat transfer performance in granular flow target, validation and verification in principle research facility, and comparative discussion.The key issues including design parameter effect on flow rate, packing status in target section, velocity distribution in coupling region and etcetera. Positive results of these issues supported the design and built up of electron-beam coupling recirculation loop. The loop sustained well and the results agreed well with numerical results. For further illustration of heat transfer and design features of granular flow target, comparison was made in the aspects of coupling region flow and research and development method.Results from the work showed the granules target material in DGT has its potential for high power transfer under beam coupling condition. Compare to the liquid target material, granular flow formed a well-shaped beam-coupling surface, which is crucial during the operation. The properties of granular material lead to the feasibility of target system especially for windowless situation. Facilities including electron-beam-coupled DGT loop, water loop for liquid target flow test, and other devices for heat and flow tests were designed, build and operated during this dissertation. The accordance of experiments and simulations was verified. While offering the basic research condition of the key issues, these facilities also provide the experience of systematic operation and estimation of factors. This dissertation gives supportive evidence for further project implementation.In the dissertation, 1st chapter is background review, and the 2nd chapter is issue investigation. Independent work is stated through chapter 2 to 5, in which chapter 5 is comparative research.