Application of Ceramic Lattice Structures to Design Compact, High Temperature Heat Exchangers: Material and Architecture Selection.

In this work, we report the design of ceramic lattices produced via additive manufacturing (AM) used to improve the overall performances of compact, high temperature heat exchangers (HXs). The lattice architecture was designed using a Kelvin cell, which provided the best compromise among effective thermal conductivity, specific surface area, dispersion coefficient and pressure loss, compared to other cell geometries. A material selection was performed considering the specific composition of the fluids and the operating temperatures of the HX, and Silicon Carbide (SiC) was identified as promising materials for the application.

Nature-Inspired, Ultra-Lightweight Structures with Gyroid Cores Produced by Additive Manufacturing and Reinforced by Unidirectional Carbon Fiber Ribs.

This article reports on a nature-inspired, ultra-lightweight structure designed to optimize rigidity and density under bending loads. The structure's main features were conceived by observing the scales of the butterflies' wings. They are made of a triply periodic minimal surface geometry called gyroid and further reinforced on their outer regions with a series of ribs.

Effect of ZrB addition on the oxidation behavior of Si-SiC-ZrB composites exposed at 1500°C in air.

Background: Silicon carbide ceramics obtained by reactive infiltration of silicon (SRI) have many industrial applications especially involving severe and high temperature conditions. In this study, the oxidation behavior in air of Si-SiC-ZrB systems at a high temperature (1500°C) for dwelling times of up to 48 hours was examined.

Methods: The oxidation process was analyzed on the basis of elemental maps and X-ray diffraction patterns taken, respectively, on the core and on the surface of the specimens, together with weight gains and the average thicknesses of the resulting scale.

Coarse-graining MARTINI model for molecular-dynamics simulations of the wetting properties of graphitic surfaces with non-ionic, long-chain, and T-shaped surfactants.

We report on a molecular dynamics investigation of the wetting properties of graphitic surfaces by various solutions at concentrations 1-8 wt. % of commercially available non-ionic surfactants with long hydrophilic chains, linear or T-shaped. These are surfactants of length up to 160 Å.

Wetting and contact-line effects for spherical and cylindrical droplets on graphene layers: a comparative molecular-dynamics investigation.

In molecular dynamics (MD) simulations, interactions between water molecules and graphitic surfaces are often modeled as a simple Lennard-Jones potential between oxygen and carbon atoms. A possible method for tuning this parameter consists of simulating a water nanodroplet on a flat graphitic surface, measuring the equilibrium contact angle, extrapolating it to the limit of a macroscopic droplet, and finally matching this quantity to experimental results. Considering recent evidence demonstrating that the contact angle of water on a graphitic plane is much higher than what was previously reported, we estimate the oxygen-carbon interaction for the recent SPC/Fw water model.