氘氚聚变中子发生器旋转氚靶传热特性研究

Heat transfer analysis of rotating tritium target of deuterium-tritium fusion neutron generator

强流氘氚中子发生器可用于模拟聚变堆中子环境,对于开展聚变堆包层材料相关实验研究具有重要意义.本文提出了一种用于1012n·s 1量级氘氚中子发生器HINEG(high intensity neutron generator)的旋转氚靶系统设计方案,并对其技术难点和强化传热方法进行了介绍.为考查该氚靶系统的传热特性,利用Computational Fluid Dynamics方法对冷却水层厚度、冷却水流速和氚靶系统旋转速度对靶面冷却的影响进行了分析,并对不同热功率密度下靶面的传热过程进行了研究.结果显示,大的水层厚度、大的冷却水流速和高的靶系统旋转速度有利于靶面的冷却,但水层厚度和水流速的变化对靶面传热影响较小.一定条件下靶面所承受的热功率密度不能超过某个限值.

Fusion reactor is considered as one of the solutions for the sustaining development of nuclear energy. International Thermonuclear Experimental Reactor （ITER） is the biggest fusion reactor research plan in the world. High-intensity D-T fusion neutron generator can generate 14 MeV neutrons, and it matches the neutrons generated in ITER and be competently used for imitating the neutron environment in nuclear fusion reactor, which is important for the relevant experimental researches of blanket materials of fusion reactors. It can also be used for validating the correctness and reliability of the simulations and analyses in fusion basic studies, and can guide the subsequent material improvement and innovation of calculation methodology. A rotating tritium target system for D-T fusion neutron generator with a neutron yield of 1012 n.s-1, i.e., a high intensity D-T fusion neutron generator, is proposed in this paper and the design, main parameters, technical difficulties and heat transfer enhancement method are introduced. The key and innovative technology of this rotating target system is the integration of the sprayed water cooling, mechanical seal and magnetic fluid seal technologies, which focuses on the heat transfer of the high heat power density in the target system. The most important technical index is that the maximum temperature on the target should not be above 200 ~C as the tritium ions run away heavily from the tritium target when the target temperature is bigger than 200 ~C. To investigate the heat transfer characteristics of this rotating target system, the effects of water layer thickness, water flow rate and rotating speed on the heat transfer of this rotating target system are analyzed by computational fluid dynamics method. And the heat transfer processes of the target system under different heat power densities are also simulated and studied. The analysis results show that big water layer thickness, big water flow rate and high rotating speed are good for the heat transfer enhancement of the rotating target system, but the effects of the changes of the water layer thickness and water flow rate on the heat transfer process are both very small. Due to the design index, the heat power density on the target should be under a limit value, which is about 12 kW·cm-2 in the calculation results of this paper.