冷却气体对黑腔系统温度场影响数值模拟

Numerical Simulation of Cooling Gas Effect on Temperature Distribution inside Cryotarget System

为了研究氦氢冷却气体对黑腔系统温度场的影响,采用CFD数值模拟方法,计算了氘氚靶丸外表面最大温差与填充区域的气体流场随气压、氦气含量变化的规律。通过对冷却壁面施加壁温扰动函数,监测了靶丸外表面平均温度、最大温差随时间的波动。研究结果表明:提高氦氢混合气体的填充压力或减小氦气含量,使得黑腔上下部分冷却气体自然对流强度差异增大,导致靶丸外表面温度场均匀性恶化;但降低冷却气体中氦气含量使气体导热系数减小,比热容增大,使得冷却壁温扰动对靶丸外表面温度场均匀性的影响减弱。

In order to study the effect of cooling gas on the temperature distribution around the capsule and the hohlraum,CFD simulation was conducted to obtain the maximum temperature gradient on the deuterium-tritium capsule surface and the gas flow field when the hohlraum filled in different helium content gaseous mixtures under different gas pressures.In addition,the variations of the average temperature and the maximum temperature gradient on the capsule surface were recorded under the condition that the cooling walls were applied to thermal oscillation.The results indicate that increasing the gas pressure or decreasing the helium content enhances the natural convection difference between the upper and lower gas regions,which results in the worse temperature gradient on the capsule surface.While,decreasing the helium content in the cooling gas which gets lower thermal conductivity and higher specific heat reduces the influence of cooling wall temperature fluctuating on the temperature distribution around capsule.