Heat Transfer in Carbon-Nanotube Dispersions: A Simulation Study of the Role of Nanotube Morphology and Connectivity.

Simulation of the behavior of carbon nanotubes (CNTs) can become a very challenging task considering their complicated shape and large aspect ratio. This study aims to elucidate the role of CNT shape, length, and connectivity during heat transfer in CNT dispersions through a three-dimensional (3D) simulator. Three characteristic shapes for the CNTs are considered, namely, straight, moderately curved, and strongly curved.

Thermal Conduction in Hybrid Nanofluids and Aggregates.

Hybrid nanofluids contain more than one type of nanoparticle and have shown improved thermofluidic properties compared to more conventional ones that contain a single nanocomponent. Such hybrid systems have been introduced to improve further the thermal and mass transport properties of nanoparticulate systems that affect a multitude of applications. The impact of a second particle type on the effective thermal conductivity of nanofluids is investigated here using the reconstruction of particle configurations and prediction of thermal efficiency with meshless methods, placing emphasis on the role of particle aggregation.

Modelling Thermal Conduction in Polydispersed and Sintered Nanoparticle Aggregates.

Nanoparticle aggregation has been found to be crucial for the thermal properties of nanofluids and their performance as heating or cooling agents. Most relevant studies in the literature consider particles of uniform size with point contact only. A number of forces and mechanisms are expected to lead to deviation from this ideal description.

Modelling Thermal Conduction in Nanoparticle Aggregates in the Presence of Surfactants.

Many theoretical and experimental studies have shown that the addition of nanoparticles into conventional fluids may generate nanofluids with significantly improved heat transfer properties. In the present work, the effect of nanoparticle aggregation on the thermal conductivity of nanofluids is studied, considering also the effect of surfactants that are typically added to stabilise the nanofluid. A method for simulating aggregate formation is developed here that allows tailoring of the fractal dimension and the number density of the nanoparticles to desired values.

Three-Dimensional Digital Reconstruction of TiAlC Ceramic Foams Produced by the Gelcast Method.

Α digital reconstruction technique is presented that generates three-dimensional (3D) digital representations of ceramic foams created by the foam-gelcasting technique. The reconstruction process uses information that is directly extracted from Scanning Electron Microscopy (SEM) images and offers a 3D representation of the physical sample accounting for the typically large pore cavities and interconnecting windows that are formed during the preparation process. Contrary to typical tessellation-based foam treatments, a spherical representation of the pores and the pore windows of the foams is assumed and a novel hybrid algorithm that combines a variation of Lubachevsky-type and Random Close Packing of Hard Spheres (RCPHS) algorithms has been developed to obtain near-optimum solutions to the packing problem of the spheres that represent the pores.

Advanced Laguerre Tessellation for the Reconstruction of Ceramic Foams and Prediction of Transport Properties.

Ceramic foams are promising, highly porous materials, with a wide range of specific surface area and low fluid flow resistance, which are well-suited for filtering applications. They are comprised mainly of macrovoids that are interconnected with struts. A branch-shaped reconstruction algorithm is introduced in the present work to reconstruct various ceramic foams from electron microscopy images using the Laguerre tessellation method.

Real-time tumor ablation simulation based on the dynamic mode decomposition method.

Purpose: The dynamic mode decomposition (DMD) method is used to provide a reliable forecasting of tumor ablation treatment simulation in real time, which is quite needed in medical practice. To achieve this, an extended Pennes bioheat model must be employed, taking into account both the water evaporation phenomenon and the tissue damage during tumor ablation.

Methods: A meshless point collocation solver is used for the numerical solution of the governing equations.

Temperature distribution inside an evaporating two-dimensional droplet lying on curved or flat substrates.

The temperature field inside an evaporating two-dimensional droplet resting on curved or flat isothermal substrates is studied under various evaporation conditions. An analytical solution for the temperature is derived, which can be directly used in the cases of pinned and depinned contact lines as well as in stick-slip evaporation modes. It is found that the temperature drop at the free surface of a droplet on a convex, hydrophobic substrate is far greater than that for flat or concave substrates of the same hydrophobicity.

Transport of hydrocarbons from an emplaced fuel source experiment in the vadose zone at Airbase Vaerløse, Denmark.

An emplaced hydrocarbon source field experiment was conducted in the relatively homogeneous sandy geology of the vadose zone at Airbase Vaerløse, Denmark. The source (10.2 l of NAPL) consisted of 13 hydrocarbons (n-, iso- and cyclo-alkanes and aromates) and CFC-113 as a tracer.