基于开放栅格结构的空间堆三维热工水力特性研究

Study on Three-dimensional Thermal-hydraulic Characteristics of a Space Reactor based on Open Lattice Structure

高温气冷堆结合磁流体发电是一种高效的空间电源系统,可以满足空间任务对于大功率、高效率的需求,具有广阔的应用前景。本文参考美国普罗米修斯计划中的开放栅格方案,结合磁流体发电需满足的设计条件,提出了一种由三角形布置、217根燃料棒构成的堆芯方案。在通过试验数据确定流动模型后,对该空间堆进行了三维建模,并在考虑气隙结构、燃料棒功率分布及堆内辐射的基础上研究其热工水力特性,重点针对环境温度及外壁面发射率展开了热工参数敏感性分析。计算结果表明,该堆芯热工设计满足材料温度、压降限值等指标要求。冷却剂在燃料区横向流动不明显,不存在复杂涡结构,流动现象相对较为简单。稳态热工计算结果对环境温度的改变并不敏感,但发射率的改变影响相对较大。

High temperature gas cooled reactor combined with magnetohydrodynamic(MHD)power generation is an efficient space power system.It can meet the requirements in space tasks for high power and high efficiency and thus has broad application prospects.In this paper,a core scheme composed of 217 fuel rods in a triangular arrangement is proposed in accordance with the design conditions to be met for MHD power generation and with the reference to the open lattice scheme in Prometheus Project.The three-dimensional modeling of the space reactor is carried out after determining the flow model through the experimental data.The thermal-hydraulic characteristics are studied on the basis of taking into consideration the gap structure,the fuel rod power distribution and the in-reactor radiation.Finally,sensitivity analysis on thermal parameters is carried out mainly for the ambient temperature and the external surface emissivity.The calculation results show that the thermal design of the core meets the requirements of material temperature and pressure drop limit.The transverse flow of coolant in the fuel area is not obvious and there is no complex vortex structure.The flow phenomenon is relatively simple.The steady-state thermal calculation results are not sensitive to the change of ambient temperature,but the change of emissivity has a relatively large impact.