Numerical and experimental investigation on the thermal insulation performance of low temperature cold box

摘要

A new modeling method with the discrete ordinate (DO) model and GKT model was proposed to simulate the thermal insulation performance of a low temperature cold box. Experimental data from the thermal insulation experiment of a cold box were used to validate the model. The thermal insulation performance and the coupled radiation and conduction heat transfer were analyzed at various pressures, shield numbers and shield positions. The results confirmed that the thermal insulation performance can be significantly improved by the addition of a thermal insulation shield. It was found that the effects of shield position on the thermal insulation performance are different at lower pressure (<3×10~(-2)Pa) from higher pressure. A practical application was presented by the usage of the new model in analyzing the performance of the cold box in a cold neutron source. A composite thermal insulation method was proposed to reduce the cold loss by 18.3% and 9% respectively compared with those with the aluminum foil wrapping and shield insulating methods.