Laser Short-Pulse Heating of a Three Layer Assembly and the Seebeck Effect

Laser short pulse heating of a multi-layer assembly, which consists of different layer properties, results in a non-similar electron and lattice site temperature distributions in the layers. This is because the differences in the amount of energy transfer in each layer despite the fact that each layer is very thin. Consequently, an investigation into the temperature distribution in the electron and lattice subsystems in each layer is essential. In the present study, laser short-pulse heating of a three layer assembly, consisting of Au-Cr-Cu, is examined. The electron and lattice site temperature rise in each layer is predicted using an electron lattice theory approach. Three-dimensional heating situation is accommodated in the model study. The Seebeck coefficient in each layer is computed and compared with the results of the previously derived equation. It is found that the electron temperature distribution varies in each layer and that this variation affects the lattice site temperature distribution. The lattice temperature distribution in the radial direction is not influenced by the diffusion of energy in the radial direction. Abrupt changes in the Seebeck coefficient across chromium and copper layers are observed

Laser Short-Pulse Heating of a Three Layer Assembly and the Seebeck Effect

Laser short pulse heating of a multi-layer assembly, which consists of different layer properties, results in a non-similar electron and lattice site temperature distributions in the layers. This is because the differences in the amount of energy transfer in each layer despite the fact that each layer is very thin. Consequently, an investigation into the temperature distribution in the electron and lattice subsystems in each layer is essential. In the present study, laser short-pulse heating of a three layer assembly, consisting of Au-Cr-Cu, is examined. The electron and lattice site temperature rise in each layer is predicted using an electron lattice theory approach. Three-dimensional heating situation is accommodated in the model study. The Seebeck coefficient in each layer is computed and compared with the results of the previously derived equation. It is found that the electron temperature distribution varies in each layer and that this variation affects the lattice site temperature distribution. The lattice temperature distribution in the radial direction is not influenced by the diffusion of energy in the radial direction. Abrupt changes in the Seebeck coefficient across chromium and copper layers are observed

Investigation Into The Seebeck Coefficient in Two-Layer Assembly During Laser Short-Pulse Heating

The Seebeck coefficient in a substrate varies with electron temperature such that it increases with increasing temperature. The Seebeck coefficient for different materials differs even though the materials have similar thermal properties. In this study, the Seebeck coefficient in a two-layer assembly exposed to laser short-pulse heating is considered. The assembly consists of gold and copper, and the gold layer is situated on top of the copper. In order to investigate the change in the Seebeck coefficient with layer thickness, three different thicknesses of gold layer are accommodated in the simulations. An abrupt change in the Seebeck coefficient occurs across the layers, despite the smooth decay of electron temperatures in this region due to the similar thermal properties of the layer materials. Consequently, the Seebeck coefficient variation across the layers can form the basis for measurement of layer thickness

Investigation Into The Seebeck Coefficient in Two-Layer Assembly During Laser Short-Pulse Heating

The Seebeck coefficient in a substrate varies with electron temperature such that it increases with increasing temperature. The Seebeck coefficient for different materials differs even though the materials have similar thermal properties. In this study, the Seebeck coefficient in a two-layer assembly exposed to laser short-pulse heating is considered. The assembly consists of gold and copper, and the gold layer is situated on top of the copper. In order to investigate the change in the Seebeck coefficient with layer thickness, three different thicknesses of gold layer are accommodated in the simulations. An abrupt change in the Seebeck coefficient occurs across the layers, despite the smooth decay of electron temperatures in this region due to the similar thermal properties of the layer materials. Consequently, the Seebeck coefficient variation across the layers can form the basis for measurement of layer thickness

Focusing of phase change microparticles for local heat transfer enhancement in laminar flows

Phase change material (PCM) suspensions have received wide spread attention for increased thermal storage in various thermal systems such as heat sinks for electronics and solar thermal applications. To achieve further heat transfer enhancement, this paper investigates the effect of focusing micron-sized phase-change particles (PCMs) to a layer near the heated wall of a parallel plate channel. A numerical model for fully-developed laminar flow with a constant heat flux applied to one wall is developed. Melting of the focused PCMs is incorporated using a temperature-dependent effective heat capacity. The effect of channel height, height of the focused PCM stream, heat flux, and fluid properties on the peak local Nusselt number (Nu∗) and the averaged Nusselt number over the melting length (Nu[subscript melt]) are investigated. Compared to the thermally-developed Nusselt number for this geometry (Nuo = 5.385), Nu[subscript melt]and Nu∗ enhancements of 8% and 19% were determined, respectively. The local heat transfer performance is optimized when the PCMs are confined to within 30% of the channel height. The present work provides an extended understanding of local heat transfer characteristics during melting of flowing PCM suspensions, and offers a new method for enhancing heat transfer performance in various thermal-fluidic systems