黑腔冷冻靶传热与自然对流的数值模拟研究  

Numerical simulation of heat transfer and natural convection of the indirect-driven cryogenic target

作　　者：黄鑫[1] 彭述明[1] 周晓松[1] 余铭铭[1] 尹剑[1] 温成伟[1] 

机构地区：[1]中国工程物理研究院核物理与化学研究所,绵阳621900

出　　处：《物理学报》2015年第21期311-318,共8页Acta Physica Sinica

基　　金：国家重大专项;中国博士后科学基金(批准号:2014 M552382)资助的课题~~

摘　　要：惯性约束聚变的设计要求在靶丸内形成均匀光滑的氘氚冰层,靶丸周围的热环境对冰层的质量特别是低阶粗糙度有很大的影响.本文对自主研发的黑腔冷冻靶实验装置中的热物理问题展开了数值模拟,重点考察了黑腔冷冻靶的传热和流体力学特性.通过参数分析得到了自然对流对靶丸温度均匀性产生影响的临界条件.比较了黑腔不同布置朝向时的流场和温度分布,结果显示黑腔水平布置时自然对流更加强烈,造成的靶丸温度不均匀性也更大.在此基础上,讨论了消除自然对流影响的可能性,结果发现仅当黑腔垂直布置时利用黑腔分区方法能够消除对流效应对靶丸温度不均匀性的影响而黑腔水平布置时不能消除.研究结论对于实验中冷冻靶结构的设计、改进和实验的开展等具有指导意义.ICF design requires smooth and uniform deuterium-tritium（D-T） ice layers in a spherical shell. Thermal environment around the capsule is the key to reach the low-mode ice layer roughness requirement and obtain a high quality ice layer. In this paper, we present the results of three-dimensional simulation for an indirect-driven cryogenic target,focusing on the issues of heat transfer and natural convection flow inside the hohlraum. A thermal and hydrodynamic calculation is first proposed to investigate the convection heat transfer effect on the D-T ice layer. Comparing the two cases with gravity considered or neglected, we find that the temperature variation at the ice layer inner surface caused by the natural convection flow and the hohlraum＇s structure are of the same order of magnitude. Then the parameters study on Rayleigh number, which is a dimensionless number associated with free convection, is carried out. Thermal simulations on different Rayleigh number are provided. Temperature variation at the D-T ice layer inner surface is to increase as soon as the Rayleigh number reaches 60. Comparisons among different gases under different operating pressure conditions are made. In order to avoid the convection heat transfer effect in a wide range of pressure, it is necessary to take pure helium or mixture gas with a small amount of hydrogen as the tamping gas. The influence of hohlraum＇s orientation on the natural convection is also studied. It is found that the convective heat transfer effect in a horizontally orientated hohlraum is stronger than that in a vertical one. Based on these, we discuss the possibility to eliminate the convection flow by partitioning the hohlraum into several regions. The calculated results for several cases of different gas-region models indicate that the convection flow can be eliminated with an appropriate division in a vertically orientated hohlaum but cannot in a horizontally orientated one. The conclusions in this paper have certain guiding significance for further design a

关 键 词：惯性约束聚变 冷冻靶 自然对流 热模拟 

分 类 号：TL632[核科学技术—核技术及应用]