Effect of Colloidal Chemistry on the Thermal Conductivity of Nanofluids

2006 ◽  
Author(s):  
Ravi Prasher
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Surface Chemistry ◽  
Thermal Transport ◽  
High Thermal Conductivity ◽  
Aggregation Kinetics ◽  
Effect Of Ph ◽  
Colloidal Chemistry ◽  
The World ◽  
Increasing Temperature

Nanofluids have attracted tremendous attention lately due to their promise as high thermal conductivity liquid and also due the inability of researchers all across the world in explaining the enhancement in the thermal conductivity. Various models and physics have been proposed and some of them have been quite successful in explaining the data, however none of the models in the literature take colloidal chemistry into account. Experimental data, however have shown dependence of thermal conductivity on pH and surface chemistry. In this paper we introduce a model which captures all the anomalies reported in the data 1) Effect of pH 2) effect of aging i.e. time 3) maxima in the thermal conductivity with respect to the diameter of the nanoparticles 4) increase and decrease in the ratio of the thermal conductivity of the nanofluids and the base fluids with increasing temperature. The model is based on the combination of aggregation kinetics with the physics of thermal transport.

Monolayer and bilayer polyaniline C3N: two-dimensional semiconductors with high thermal conductivity

Nanoscale ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 4301-4310 ◽  
Author(s):  
Yang Hong ◽  
Jingchao Zhang ◽  
Xiao Cheng Zeng
Keyword(s):  
Thermal Conductivity ◽  
Thermal Transport ◽  
Md Simulation ◽  
Transport Processes ◽  
High Thermal Conductivity ◽  
Two Dimensional

Lateral and flexural thermal transport processes in monolayer and bilayer C3N are systematically investigated using MD simulation.

scholarly journals Graphene oxide-loaded shortening as an environmentally friendly heat transfer fluid with high thermal conductivity

2017 ◽  
Vol 21 (5) ◽  
pp. 2247-2254
Author(s):  
Thammasit Vongsetskul ◽  
Peeranut Prakulpawong ◽  
Panmanas Sirisomboon ◽  
Jonggol Tantirungrotechai ◽  
Chanasuk Surasit ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Graphene Oxide ◽  
Environmentally Friendly ◽  
High Thermal Conductivity ◽  
Chemical Degradation ◽  
Heat Transfer Fluid ◽  
Increasing Temperature ◽  
Scanning Electron

Graphene oxide-loaded shortening (GOS), an environmentally friendly heat transfer fluid with high thermal conductivity, was successfully prepared by mixing graphene oxide (GO) with a shortening. Scanning electron microscopy revealed that GO particles, prepared by the modified Hummer?s method, dispersed well in the shortening. In addition, the latent heat of GOS decreased while their viscosity and thermal conductivity increased with increasing the amount of loaded GO. The thermal conductivity of the GOS with 4% GO was higher than that of pure shortening of ca. three times, from 0.1751 to 0.6022 W/mK, and increased with increasing temperature. The GOS started to be degraded at ca. 360?C. After being heated and cooled at 100?C for 100 cycles, its viscosity slightly decreased and no chemical degradation was observed. Therefore, the prepared GOS is potentially used as environmentally friendly heat transfer fluid at high temperature.

Theoretical Analysis of Thermal Conductivity in Amorphous Inter-layer Dielectrics

2006 ◽  
Vol 914 ◽  
Author(s):  
Manu Shamsa ◽  
Patrick Morrow ◽  
Shriram Ramanathan
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Thermal Transport ◽  
High Frequency ◽  
Thermal Conduction ◽  
High Performance ◽  
Amorphous Materials ◽  
Disordered Materials ◽  
Semiconductor Processing ◽  
Hopping Model

AbstractUnderstanding thermal conduction in interlayer dielectrics (ILDs) is important for the optimal design of interconnect layers in backend semiconductor processing for future high-performance nano-scale devices. Reduced thermal conductivity of porous ILDs for example can adversely affect the temperature rise in the embedded metal lines leading to un-desirable reliability issues and design constraints. In this paper, we report results of our theoretical and experimental investigation of thermal transport in amorphous and porous dielectrics. A phonon-hopping model has been adapted to calculate the thermal conductivity in disordered materials. The value of hopping integral has been calculated by comparing the modeling results with experimental data for various amorphous and porous materials. The model shows reasonable agreement with experimental data for various amorphous materials including SiO2 and other glasses over a wide temperature range from 50K – 300K. The model suggests that the hopping of localized high frequency phonons is a dominant thermal transport mechanism in such material systems.

Predicting Thermal Transport in Bi2Te3: From Bulk to Nanostructures

2011 ◽  
Vol 1329 ◽  
Author(s):  
Bo Qiu ◽  
Xiulin Ruan
Keyword(s):  
Experimental Data ◽  
Thin Films ◽  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Thermal Transport ◽  
Morse Potential ◽  
Density Functional ◽  
Energy Surface ◽  
Nanowire Diameter ◽  
Potential Form

ABSTRACTTwo-body interatomic potentials in the Morse potential form have been developed for bismuth telluride, and the potentials are used in molecular dynamics (MD) simulations to predict the thermal conductivity of Bi2Te3 bulk, nanowires and few-quintuple thin films. The density functional theory with local density approximations is first used to calculate the total energies for many artificially distorted Bi2Te3 configurations to produce the energy surface. Then by fitting to this energy surface and other experimental data, the Morse potential form is parameterized. Molecular dynamics simulations are then performed to predict the thermal conductivity of bulk Bi2Te3 at different temperatures, and the results agree with experimental data well. We also predicted the thermal conductivity of Bi2Te3 nanowires with diameter ranging from 3 to 30 nm with both smooth (SMNW) and rough (STNW) surfaces. It is found that when the nanowire diameter decreases to the molecular scale (below 10 nm, or the so called "quantum wire"), the thermal conductivity shows significant reduction as compared to bulk value. We find the dimensional crossover behavior of thermal transport in few quintuple layer (QL) thin films at room temperature, and we attribute it to the interplay between phonon Umklapp scattering and boundary scattering. Also, nanoporous films show significantly reduced thermal conductivity compared to perfect thin films, indicating that they can be very promising thermoelectric materials.

Molecular Dynamics Modeling of Heat Transport in Metals and Semiconductors

2010 ◽  
Author(s):  
Sreekant Narumanchi ◽  
Kwiseon Kim
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Thermal Transport ◽  
Hybrid Electric Vehicle ◽  
Heat Dissipation ◽  
Phonon Dispersion ◽  
Interfacial Resistance ◽  
Dynamics Modeling ◽  
Molecular Dynamics Modeling

Interfacial thermal transport is of great importance in a number of practical applications where interfacial resistance between layers is frequently a major bottleneck to effective heat dissipation. For example, efficient heat transfer at silicon/aluminum and silicon/copper interfaces is very critical in power electronics packages used in hybrid electric vehicle applications. It is therefore important to understand the factors that govern and impact thermal transport at semiconductor/metal interfaces. Hence, in this study, we use classical molecular dynamics modeling to understand and study thermal transport in silicon and aluminum, and some preliminary modeling to study thermal transport at the interface between silicon and aluminum. A good match is shown between our modeling results for thermal conductivity in silicon and aluminum and the experimental data. The modeling results from this study also match well with relevant numerical studies in the literature for thermal conductivity. In addition, preliminary modeling results indicate that the interfacial thermal conductance for a perfect silicon/aluminum interface is of the same order as experimental data in the literature as well as diffuse mismatch model results accounting for realistic phonon dispersion curves.

scholarly journals Thermal Transport in Polymers: A Review

2021 ◽  
Author(s):  
Xingfei Wei ◽  
Zhi Wang ◽  
Zhiting Tian ◽  
Tengfei Luo
Keyword(s):  
Thermal Conductivity ◽  
Structural Property ◽  
Thermal Transport ◽  
Large Scale ◽  
Applied Research ◽  
Amorphous Polymers ◽  
High Thermal Conductivity ◽  
Molecular Alignments ◽  
Amorphous States ◽  
Engineering Polymers

Abstract In this article, we review thermal transport in polymers with different morphologies from aligned fibers to bulk amorphous states. We survey early and recent efforts in engineering polymers with high thermal conductivity by fabricating polymers with large-scale molecular alignments. The experimentally realized extremely high thermal conductivity of polymer nanofibers are highlighted, and understanding of thermal transport physics from molecular simulations are discussed. We then transition to the discussion of bulk amorphous polymers with an emphasize on the physics of thermal transport and its relation with the conformation of molecular chains in polymers. We also discuss the current understanding of how the chemistry of polymers would influence thermal transport in amorphous polymers and some limited, but important chemistry-structural-property relationships. Lastly, challenges, perspectives and outlook of this field are presented. We hope this review will inspire more fundamental and applied research in the polymer thermal transport field to advance scientific understanding and engineering applications.

Improving heat transfer in fused deposition modeling with graphene enhances inter filament bonding

2019 ◽  
Vol 10 (44) ◽  
pp. 5967-5978 ◽  
Author(s):  
Sahar Rostom ◽  
Mark D. Dadmun
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Transport ◽  
Fused Deposition Modeling ◽  
Polymeric Materials ◽  
Rational Method ◽  
High Thermal Conductivity ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
3D Printed

Creating polymeric materials with high thermal conductivity provides pathways to tailor the thermal transport of the 3D printed object during printing, effectively controlling heat transfer and offering a rational method to optimize properties.

scholarly journals Ionic and Thermal Transport in Na-Ion-Conducting Ceramic Electrolytes

2021 ◽  
Vol 42 (10) ◽  
Author(s):  
Magnus Rohde ◽  
Ijaz U. I. Mohsin ◽  
Carlos Ziebert ◽  
Hans Jürgen Seifert
Keyword(s):  
Thermal Conductivity ◽  
Thermal Transport ◽  
Room Temperature ◽  
Cold Isostatic Pressing ◽  
Transport Parameter ◽  
Measured Temperature ◽  
Opposite Behavior ◽  
Ceramic Electrolytes ◽  
Ion Conducting ◽  
Increasing Temperature

AbstractWe have studied the ionic and thermal transport properties along with the thermodynamic key properties of a Na-ion-conducting phosphate ceramic. The system Na1+xAlxTi2−x(PO4)3 (NATP) with x = 0.3 was taken as a NASICON-structured model system which is a candidate material for solid electrolytes in post-Li energy storage. The commercially available powder (NEI Coorp., USA) was consolidated using cold isostatic pressing before sintering. In order to compare NATP with the “classical” NASICON system, Na1+xZr2(SiO4)x(PO4)3−x (NaZSiP) was synthesized with compositions of x = 1.7 and x = 2, respectively, and characterized with regard to their ionic and thermal transport behavior. While ionic conductivity of the NaZSiP compositions was about more than two orders of magnitude higher than in NATP, the thermal conductivity of the NASICON compound showed an opposite behavior. The room temperature value was about a factor two higher in NATP compared to NaZSiP. While the thermal conductivity decreases with increasing temperature in NATP, it increases with increasing temperature in NaZSiP. However, the overall change of this thermal transport parameter over the measured temperature range from room temperature up to 800 °C appeared to be relatively small.

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