摘要
针对冷冻靶屏蔽罩开启过程温度场发生突变导致冰层质量恶化的问题,数值研究了屏蔽罩开启过程中冷冻靶温度场的瞬态特性,并提出了温度控制优化方案。数值模拟基于Boussinesq假设和离散坐标辐射模型,借助考虑辐射环境变化的冷冻靶多重屏蔽罩非稳态模型,得到了黑腔气体压力、封口膜透射率等参数的影响规律,并分析比较了在不同冷环控制方案下开罩的数值结果。研究结果表明:屏蔽罩开启后,靶丸表面绝对温度急剧升高,均匀性迅速恶化;氦气压力增大时,开罩过程的靶丸表面绝对温度无明显变化,但最大温差显著增大;减小封口膜透射率,可有效减小靶丸表面温升和最大温差;存在一个最优冷流量,使屏蔽罩开启过程中温升和最大温差在较宽的透射率范围内满足打靶要求,所满足的透射率范围相对于定壁温开罩增加了19倍。所提优化方案对冷冻靶温度控制方面具有指导意义,可为顺利打靶提供一定的先决条件。
In the present study,the transient thermal characteristics of cryogenic target during the thermal shield removal process are numerically studied,and optimal temperature control schemes are proposed to improve the target temperature distribution and to avoid ice quality deterioration.An unsteady numerical model is established for the cryogenic target with multiple thermal shields based on the Boussinesq assumption and the discrete coordinate radiation model.The transient thermal characteristics of the cryogenic target during the removal of thermal shield are analyzed under different hohlraum pressures and sealing film transmittances,and the numerical results of removal thermal shield under different control schemes of cooling rings are analyzed.The results show that the temperature on the capsule surface rises precipitously in accompany with the deterioration of temperature uniformity after removing the thermal shield.As the helium pressure in hohlraum increases,the maximum temperature difference on the capsule surface increases dramatically while the peak temperature has no significant variation.The decrease of sealing film transmittance is conducive to restrain the rises of both the maximum temperature and the maximum temperature difference.There is an optimal heat flux of cooling ring to meet the thermal requirements of ignition in a wider transmittance range which is 19 times more than that under constant temperature of cooling rings.The results can be served as a guideline for thermal preconditioning of cryogenic target before ignition.
作者
李翠
陈洵
厉彦忠
LI Cui;CHEN Xun;LI Yanzhong(School of Energy and Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China)
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2019年第7期1-7,共7页
Journal of Xi'an Jiaotong University
基金
国家重大专项资助
国家自然科学基金资助项目(51506158)
关键词
低温冷冻靶
屏蔽罩
透射率
瞬态特性
数值模拟
cryogenic target
thermal shield
transmittance
transient characteristic
numerical simulation
