低温冷箱中辐射与导热耦合传热的数值模拟

Numerical Simulation of Radiation Heat Transfer Coupled with Con duction in a Low-Temperature Cold Box

针对3种不同的隔热处理方案,对低温冷箱中辐射和导热耦合传热进行了数值模拟,同时考虑了管道、支架和横梁对系统传热的影响.计算结果表明:在相同情况下,采取设备包铝箔和加隔热屏的措施使换热器表面的辐射跑冷损失减少了2/3以上;只加铝箔隔热屏时,换热器与横梁间的热桥跑冷也得到了改善,跑冷损失减少了1/2左右.因此,在冷箱与换热器之间加铝箔隔热屏是改善低温冷箱温度分布和降低跑冷损失的一种有效方法.

Radiation heat transfer coupled with heat conduction in a low-temperature cold box involving the effect of pipes, brackets, and crossbeams on the system was numerically simulated under three different insulation schemes. The calculation results indicate that in the same condition the thermal radiation of heat exchangers can be decreased by a factor of 2/3 adding an aluminum foil covering on the equipments or an aluminum foil heat insulation screen. The thermal conduction through the brackets and crossbeams for the case with the aluminum foil heat insulation screen is only half of that compared with the case without the screen. It is concluded that adding an aluminum foil heat insulation screen is an effective way to ameliorate temperature distribution in the cold box and reduce cold energy loss from low temperature equipments.