低温冷凝泵辐射挡板结构分析与热负荷计算

减小低温板的辐射热负荷是低温泵设计中的关键问题.为了降低辐射热,通常在低温板与热源之间设置防辐射挡板,使绝大部分辐射热在挡板处被吸收.辐射挡板的副作用是阻挡了被抽气体分子运动,使低温泵的抽速降低,所以辐射挡板形式的选择对于低温泵的高效运行是至关重要的.介绍了用蒙特卡罗法对2种不同形式的辐射挡板的通导几率与透射系数进行计算与综合分析,确定了理想的挡板结构是人字型.通过对低温面辐射热负荷的计算,证明了辐射挡板对降低低温面辐射热负荷的作用显著.

THE STRUCTURAL ANALYZING AND THE HEAT LOAD CALCULATING FOR THE RADIATION BAFFLE OF CRYOCONDENSATION PUMP

To decrease the radiation heat load of the cryopanel is conside red to be necessary for the design of cryopumps.Generally,a radiation baffle is mounted between cryopanel and heat resource.A majority of the radiated heat load is absorbed by the radiation baffle.However,the motion of molecules to be pumped is baffled and the pumping speed is lowered.Therefore the selection of rad iation baffle is very important issue for the economical operation of the cryopump.Monte Carlo method is used to calculate and synthetically analyze the therma l transmission coefficient and the molecular transmission coefficient of two different structural radiation baffles.The reasonable type of Chevron baffle is obtained.By calculating the radiation heat load of the cryopanel,it is proved that the radiant heat load of the cryopanel can be cut down by the radiant baffle. The effect is remarkable.