0000000000123087
AUTHOR
Essolé Padayodi
Physical modeling of heat and moisture transfer in wet bio-sourced insulating materials.
Simultaneous heat and moisture transfers in bio-sourced insulating materials are significant phenomena in thermal metrology. The present study focuses on these phenomena by experimental and numerical approaches based on the asymmetric hot-plate method. In this paper, a bio-sourced insulating material based on flax fibers is developed. The thermal and hygric properties of the sample are then investigated in the humid atmosphere. The temperature is maintained at 30 °C, and the relative humidity varies between 30% and 90% RH. A physics-based model of simultaneous heat and moisture transfer is developed for thermal conductivity estimation. This model is discretized with finite difference method…
In-flight temperature of solid micrometric powders during cold spray additive manufacturing
Abstract During cold dynamic gas spray additive manufacturing, the thermal field within particles is generally simplified by a state of an instantaneous uniform distribution over the particle's media at any position inside and outside the De-Laval nozzle. This paper addresses critical discussions using analytical and computational analysis of the transient heat transfer within the solid particles due to the convective exchange with the flowing gas. An analytical criterion depicts conditions of instantaneous uniform temperature over the range of typical cold spray data including various particle thermal conductivity, particle size range, dragging velocities, gas nature and gas setting condit…
A new nature of microporous architecture with hierarchical porosity and membrane template via high strain rate collision
Abstract This paper presents the formation of an unusual porous structure at Al/Al interface joined by magnetic pulse welding. The porous structure consists of a hierarchical microporous architecture with pore size of less than 2 µm that represents more than 80% over the whole area, in which 38% of them are sub-micron size pores. It also exhibits ultra-thin wall, sufficiently thin enough to behave as an electron-transparent material with a wall thickness of 50 nm. The formation of this porous structure is attributed to a cavitation process of a molten material in three stages including, (1) nucleation, (2) growth and coalescence and (3) solidification. Further analysis of this cavitation pr…