Development of a technology for manufacturing a heat-shielding structure on nitrogen cryocontainers, excluding heat transfer through gas

TL;DR

This paper presents a new process for creating low-heat-conductivity thermal insulation in nitrogen cryocontainers by degassing cushioning material and replacing water molecules with dry nitrogen, reducing thermal conductivity.

Contribution

It introduces a method to accelerate vacuum achievement and lower thermal conductivity in SVTI layers by using degassed cushioning material with dry nitrogen molecules.

Findings

Achieved 11% reduction in effective thermal conductivity.

Accelerated vacuum process by 20 hours.

Optimal thermal conductivity composed of 33% radiant and 67% contact-conductive components.

Abstract

One of the important stages in the creation of the scientific and technical foundations for the calculation, design and manufacturing technology of the lowest heat-conductivity thermal protection from screen-vacuum thermal insulation (SVTI) is the development of a process for achieving the optimal vacuum in the SVTI layers, since at this pressure, thermal conductivity through the SVTI is carried out only due to the radiant and contact-conductive components. It is proposed to obtain such a pressure in thermal insulation by using cushioning material in it, which was previously degassed in a separate vacuum chamber at 370-380 K for 12 hours in order to remove water molecules from its structure and then replace them with dry nitrogen molecules. These molecules have 3-4 times less heat of adsorption; therefore they are pumped out faster. As a result, it becomes possible to accelerate (by 20 hours) to achieve optimal vacuum in thermal insulation, as well as 11% lower effective thermal conductivity. The analysis carried out (according to the developed methodology) showed that the achieved optimal effective thermal conductivity of thermal insulation in a cryocontainers is determined by 33% of radiant thermal conductivity and 67% of the contact-conductive component.