本文選題：散裂靶　切入點：顆粒流　出處：《中國科學院大學(中國科學院近代物理研究所)》2017年博士論文

【摘要】：密集顆粒流靶是為滿足ADS系統(tǒng)超高束流功率需求而提出的新型高功率散裂靶概念設計。在這基礎上,針對聚變材料研究專用中子源,近物所ADS散裂靶團隊提出了重力驅動的斜槽顆粒流靶概念設計。利用密集顆粒流作為靶材料及換熱劑,密集顆粒流靶在實現(xiàn)離線換熱功能的同時,可以避免液態(tài)重金屬的流動不穩(wěn)定、材料腐蝕、及化學毒性泄露等諸多致命缺陷,為滿足聚變材料研究專用中子源的靶系統(tǒng)提供了一種很有潛力的解決方案。作為一種新型的靶系統(tǒng)概念設計,密集顆粒流靶中的顆粒流動行為與常規(guī)液態(tài)重金屬有所不同,而最重要的區(qū)別就是流動穩(wěn)定性。本論文從分析顆粒流動穩(wěn)定性目的出發(fā),利用離散元方法模擬了顆粒在斜槽上的流動行為,通過分析顆粒速度、體積分數(shù)空間場以及它們的波動來研究流動的穩(wěn)定性,進而通過線性穩(wěn)定性分析以及計算擾動后能量差的李雅普諾夫指數(shù),進一步研究顆粒在斜槽上流動的穩(wěn)定性,此外也研究了模型的幾何及材料參數(shù)對流動的影響,最后對靶系統(tǒng)設計的可行性進行了評估。本論文主要研究三個方面的工作:(1)在周期邊界條件下,模擬了顆粒在傾斜面(規(guī)則六邊形顆粒排布)上的流動行為,主要研究了斜面傾斜角對流動的影響;(2)模擬了顆粒在斜槽的供料水庫中的流動行為,研究了模型的幾何參數(shù)對流動的影響,并分析了顆粒在供料水庫中以及斜面上的速度、體積分數(shù)空間場及它們的波動;(3)提出了斜槽顆粒流靶的概念設計,研究了模型的幾何和材料參數(shù)對流動的影響,最后通過線性穩(wěn)定性分析以及計算擾動后能量差的李雅普諾夫指數(shù),來研究顆粒在斜槽上流動的穩(wěn)定性。具體內容如下:首先我們研究了周期邊界條件下顆粒在斜面上的流動行為:首先介紹了在離散元方法中周期邊界條件的實現(xiàn)原理;然后對模型進行了描述以及對模擬過程進行了簡單介紹;最后主要分析了斜面傾斜角度對流動的影響。然后研究了顆粒在斜槽的供料水庫中的流動行為:首先分別研究了供料水庫以及斜面的傾斜角對流動的影響;然后由于供料水庫類似于偏心漏斗,研究了顆粒在偏心漏斗中的流動行為,包括漏斗寬度、開口寬度對流量的影響以及偏心漏斗中的體積分數(shù)、速度場及其波動;最后研究了供料水庫的開口高度對流動影響,包括對流量的影響以及顆粒在整個裝置體積分數(shù)、速度場及其波動。接著研究了斜槽顆粒流靶中顆粒在斜槽上的流動行為:首先我們提出了斜槽顆粒流靶的概念設計,將模擬進行了一定簡化;然后研究了模型的幾何和材料參數(shù)對流動的影響;最后通過線性穩(wěn)定性分析以及計算擾動后能量差的李雅普諾夫指數(shù),來研究顆粒在斜槽上流動的穩(wěn)定性。最后總結了全文,并展望了下一步的研究工作。
[Abstract]:Dense particle flow target is a new type of high power spallation target conceptual design proposed to meet the demand of ultra-high beam power in ADS system.On this basis, for the study of special neutron source for fusion materials, the ADS spallation target team of the near object proposed the gravity driven oblique particle flow target conceptual design.Using the dense particle flow as the target material and heat exchanger, the dense particle flow target can realize off-line heat transfer function while avoiding many fatal defects such as liquid heavy metal flow instability, material corrosion, chemical toxicity leakage and so on.It provides a promising solution for the target system of specific neutron source for fusion material research.As a new conceptual design of target system, the flow behavior of particles in dense particle flow targets is different from that of conventional liquid heavy metals, and the most important difference is the flow stability.For the purpose of analyzing the flow stability of particles, the flow behavior of particles on a chute is simulated by using discrete element method. The flow stability is studied by analyzing particle velocity, volume fraction space field and their fluctuations.Furthermore, the stability of particle flow on the slant channel is further studied by linear stability analysis and Lyapunov exponent of the energy difference after disturbance. The effects of geometry and material parameters of the model on the flow are also studied.Finally, the feasibility of target system design is evaluated.This paper mainly studies three aspects of work: 1) under the periodic boundary condition, the flow behavior of particles on inclined plane (hexagonal particle arrangement) is simulated.The effect of inclined angle on flow is studied. The flow behavior of particles in a sloping reservoir is simulated, the effect of geometric parameters of the model on flow is studied, and the velocity of particles in feed reservoir and inclined plane is analyzed.The volume fraction space field and their fluctuation are presented in this paper, and the effects of geometry and material parameters of the model on the flow are studied.Finally, the stability of particle flow in a chute is studied by linear stability analysis and Lyapunov exponent of energy difference after disturbance.The main contents are as follows: firstly, we study the flow behavior of particles on the oblique plane under periodic boundary conditions; first, we introduce the realization principle of periodic boundary conditions in discrete element method;Then the model is described and the simulation process is briefly introduced. Finally, the influence of inclined angle on the flow is analyzed.Then the flow behavior of particles in the inclined channel feed reservoir is studied. Firstly, the influence of the inclined angle of the feed reservoir and the inclined plane on the flow is studied, and then, because the feed reservoir is similar to the eccentric funnel,The flow behavior of particles in eccentric funnel is studied, including the influence of funnel width, opening width on flow rate, volume fraction, velocity field and fluctuation in eccentric funnel.It includes the influence on the flow rate and the volume fraction, velocity field and fluctuation of the particle in the whole device.Then, the flow behavior of the particles in the slit particle flow target is studied. Firstly, the conceptual design of the slanted particle flow target is proposed, and the simulation is simplified, then the effects of the geometry and material parameters of the model on the flow are studied.Finally, the stability of particle flow in a chute is studied by linear stability analysis and Lyapunov exponent of energy difference after disturbance.Finally, the paper summarizes the full text and looks forward to the next research work.
【學位授予單位】：中國科學院大學(中國科學院近代物理研究所)
【學位級別】：博士
【學位授予年份】：2017
【分類號】：O571.5

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本文編號：1726583