Numerical Investigation on Heat-Transfer and Hydromechanical Performance inside Contaminant-Insensitive Sublimators under a Vacuum Environment for Spacecraft Applications

Abstract

The contaminant-insensitive sublimator (CIS) is a novel water sublimator in development, which uses two porous substrates to separate the sublimation point from the pressure-control point and provide long-life effective cooling for spacecraft. Many essential studies need to be carried out in the field. To overcome the reliability issues such as ice breakthrough caused by large temperature or pressure differences, the CIS development unit model, the mathematical models of heat and mass transfer and the evaluation coefficient have been established. Numerical investigations have been implemented aiming at the impacts of physical properties of porous substrate, physical properties of working fluid, orifice layouts and orifice-structure parameters on the characteristics of flow field and temperature field. The numerical investigation shows some valuable conclusion, such as the temperature uniformity coefficient at the bottom surface of the large pore substrate is 0.997669 and the pressure uniformity coefficient at the same surface is 0.85361267. These numerical results can provide structure and data reference for the CIS design of lunar probe or spacesuit.

Energies and Its Worldwide Research

“…In the Special Issue "Emerging Advances in Petrophysics: Porous Media Characterization and Modeling of Multiphase Flow," Jianchao Cai and collaborators review 15 publications collected in this Special Issue devoted to experimental studies of petrophysical property characterization for unconventional resources, numerical modeling (fractal approach), and multiphase flow modeling/simulation of unconventional resources [71]. Following this theme [75], mathematical heat and mass transfer models were developed to investigate the reliability problems generated by large temperature or pressure differences. They considered the influences of the physical properties of the porous substrate, physical properties of the working fluid, arrangement of the holes, and parameters of the hole structure on the characteristics of flow and temperature field.…”

Mechanical analysis of shield machine cutter head under multiple working conditions based on elastoplastic model

“…The structure optimization provides a reference. Gao et al studied the bending moment of the cutterhead when the shield machine cuts the composite rock and soil layer during tunneling, and established a model of the total bending moment in the cutterhead plane during the tunneling of the upper layer of the composite rock by the shield machine, and performed simulation analysis [4] . Liu et al carried out the design and finite element analysis of the composite shield cutter head, and carried out a numerical analysis by simulating the structural response under the load, and the analysis results were consistent with the actual engineering [5] .…”