This study establishes a multiphysics numerical model to investigate the evaporation dynamics of nanofluid droplets on heated substrates by employing the Arbitrary Lagrangian-Eulerian (ALE) method. The model fully couples internal and external fluid flow, heat transfer, and mass transport, while tracking nanoparticle motion within the droplet through a particle-tracing approach. Particular attention is given to the evolution of temperature fields, vapor concentration distributions, interfacial mass fluxes, and the trajectories of suspended nanoparticles during different evaporation stages. The results show that substrate heating and surface evaporative cooling jointly establish a surface tension gradient that drives Marangoni circulation within the droplet. As the droplet gradually flattens, the internal flow evolves from a single vortex into a multiple-vortex structure, with four vortices forming at 70 s during late-stage evaporation. This multiple-vortex structure persists for approximately 12 s, causing local perturbations in interfacial temperature and evaporation flux. The evaporative mass flux at the liquid-gas interface is higher near the droplet edge than at the center. During early evaporation, the mass flux near the edge reaches approximately 0.03 kg/(m²·s). As evaporation proceeds, the convective mass flux gradually decreases, whereas the diffusive mass flux remains relatively stable at approximately 0.005 kg/(m²·s). Nanoparticles migrate and accumulate under the influence of the internal flow, becoming trapped at the liquid-gas interface or deposited on the substrate. These findings reveal the coupling among temperature, flow, and mass transport, as well as nanoparticle migration patterns during nanofluid droplet evaporation. They provide a theoretical reference for the application of nanofluid working fluids in loop heat pipes for space applications.

Integrating phase change materials (PCM) into thermal insulation materials offers a novel approach to aerospace thermal protection. Herein, we used waste biomass as a template; by selecting the appropriate carbonization temperature, we obtained carbon aerogels (CCA) with extremely high porosity (95.8%) and high pore volume. After encapsulating PEG2000, we achieved high enthalpy (137.79 J g⁻¹, 91% of pure PEG2000) and low thermal conductivity (0.137 W (m·K)⁻¹, 45% of pure PEG2000). Thanks to the rich hierarchical nano-micro porous structure of CCA and the high latent heat of PEG2000, CCA/PEG exhibits excellent thermal insulation properties (under a heating temperature of 131 ℃, the material takes 1400 s to reach its maximum temperature and can be maintained below 65 ℃) and cycle performance. Additionally, irradiation destroyed the structure of CCA/PEG, leading to the degradation of PEG and the formation of other carbonyl-containing compounds, which decreased its latent heat (4.2%) and thermal conductivity (16.1%). However, the irradiation-resistant CCA, acting as a protective layer, minimizes the impact of irradiation on PEG2000. Instead, irradiation enhances the hierarchical porous structure of the material, ultimately improving its thermal insulation performance. CCA/PEG has potential application prospects in thermal protection and aerospace and is a strong competitor for high-efficiency thermal insulation materials.

When nano-fillers are used to enhance the thermal conductivity of organic phase change materials (PCMs), the naturally formed interface is considered to hinder thermal transport of the composite PCMs. However, the effect of the interface on the thermal properties of surrounding PCM has not been fully studied. In this paper, three composite PCMs (Ery@SiC, Ery@SiO₂ and Ery@Si₃N₄) were prepared by melt-blending method. The local thermal conductivity and reduced Young’s modulus (E*) of the erythritol at the interface and far away from the interface in the composite PCMs were simultaneously measured by scanning thermal microscopy (SThM). The results revealed significant enhancement in local thermal conductivity of erythritol at the interface and its obvious positive correlation with E*. For different composite PCMs, molecular dynamics (MD) simulations suggested that the increase in intrinsic thermal conductivity and E* of erythritol is attributed to the increase in interaction energy between erythritol and nanoparticles, as more erythritol phonon vibrations transform from localized mode to delocalized mode and erythritol has a higher density at the interface. These findings will provide new ideas for the design of PCM for energy storage.

The revelation of thermal energy exchange mechanism of human body is challenging yet worthwhile, because it can clearly explain the changes in human symptoms and health status. Understanding, the heat transfer of the skin is significant because the skin is the foremost organ for the energy exchange between the human body and the environment. In order to diagnose the physiological conditions of human skin without causing any damage, it is necessary to use a non-invasive measurement technique by means of a conformal flexible sensor. The harmonic method can minimize the thermal-induced injury to the skin due to its low heat generating properties. A novel type of computational theory assessing skin thermal conductivity, blood perfusion rate of capillaries in the dermis, and superficial subcutaneous tissues was formed by combining the multi-medium thermal diffusion model and the bio-thermal model (Pennes equation). The skins of the hand back of six healthy subjects were measured. It was found that the results revealed no consistent changes in thermal conductivity were observed across genders and ages. The measured blood perfusion rates were within the range of human capillary flow. It was found that female subjects had a higher perfusion rate range (0.0058–0.0061 s⁻¹) than male subjects (0.0032–0.0049 s⁻¹), which is consistent with invasive medical studies about the gender difference in blood flow rates and stimulated effects in relaxation situations.