冷冻靶屏蔽罩温度扰动动态特性分析

Dynamic Thermal Characteristics of Cryogenic Target Under Temperature Disturbance of Thermal Shield

针对屏蔽罩温度波动导致冷冻靶燃料冰层均匀性降低的问题,基于用户自定义函数和离散坐标辐射模型,研究了辐射环境变化时黑腔冷冻靶系统的温度场动态特性,得到套筒吸收率和封口膜透射率等参数对靶丸表面温度场稳定性、均匀性的影响规律。结果表明:屏蔽罩温度波动有两条传播路径,路径一为屏蔽罩封口膜靶丸,路径二为屏蔽罩套筒金腔氦气腔靶丸;典型工况下屏蔽罩振幅10 K的温度波动到靶丸外壁时衰减为0.85 mK,黑腔系统各表面温度振幅由大到小为靶丸外壁、套筒外壁、套筒内壁、金腔内壁;当封口膜透射率较小时减小套筒吸收率,或封口膜透射率较大时增大套筒吸收率,或减小封口膜透射率,均可显著提高靶丸表面温度场稳定性和均匀性。

Dynamic thermal characteristics of cryogenic targets are studied under conditions of temperature disturbance of the thermal shield.Based on user-defined functions and the discrete coordinate radiation model,a model is numerically developed and the propagation characteristics of the temperature disturbance in the hohlraum system are studied.The influences of the thermal mechanical package(TMP)shell absorptivity and the sealing film transmissivity on the stability and uniformity of the capsule surface temperature field are obtained.The results show that the temperature fluctuation of the shield has two paths.The first path is the shield-sealing film-capsule and the second one is the shield-TMP-gold hohlraum wall-helium chamber-capsule.Under typical operating conditions,the temperature fluctuation of shield with amplitude 10 K is attenuated to 0.85 mK at the outer wall of the target.The temperature amplitude of each surface of the hohlraum system varies from large to small:the outer wall of the target,the outer wall of TMP,the inner wall of TMP,and the inner wall of gold hohlraum.The stability and uniformity of the capsule temperature is significantly improved by decreasing the TMP shell absorptivity when the sealing film transmissivity is small,or increasing the TMP shell absorptivity when the sealing film transmissivity is large,or decreasing the sealing film transmissivity.