Interfacial Thermal Resistance Between a Carbon Nanoparticle and Molten Salt Eutectic: Effect of Material Properties, Particle Shapes and Sizes

2011 ◽  
Author(s):  
Byeongnam Jo ◽  
Debjyoti Banerjee
Keyword(s):  
Particle Size ◽  
Thermal Resistance ◽  
Molten Salt ◽  
Thermal Power ◽  
Carbon Particle ◽  
Interfacial Thermal Resistance ◽  
Graphite Sheet ◽  
Carbon Particles ◽  
Different Shapes ◽  
Particle Shapes

The aim of this study is to estimate the interfacial thermal resistance between a carbon nano-particle and alkali molten salt eutectics using molecular dynamics simulations. Additionally the effect of particle shapes and sizes on the interfacial thermal resistance was investigated using three different shapes of the carbon nanoparticles. Transient heat transfer simulation between a carbon particle and molecules of a molten salt was performed with the lumped capacitance method. A carbonate salt eutectic which consists of lithium carbonate (Li2CO3) and potassium carbonate (K2CO3) in 62:38 molar ratio was used as a solvent medium for the nanoparticles. Three carbon particles of a single walled carbon nanotube (SWNT), a fullerene (C60), and a graphite sheet were used to represent different shapes of cylinders, a spheres, and disks, respectively. The interfacial thermal resistance was determined by a correlation with a specific heat of the carbon particle, their surface area, and the time constant of decaying particle temperature. The results show the interfacial thermal resistance values are independent of the particle size for SWNT and graphite particles. For three carbon particles with a similar particle size, similar resistances were obtained in our simulations. The purpose of this study is to design and develop novel high-temperature Thermal Energy Storage (TES) materials in order to improve the operational efficiencies for harnessing solar thermal power at cheaper costs for Concentrated Solar Power (CSP) systems.

Effect of Carbon Particle Feeding as Radiant Absorbent for Enhanced Heat Transfer

2021 ◽  
pp. 1-15
Author(s):  
Hamed Abedini ◽  
Nesrin Ozalp
Keyword(s):  
Heat Transfer ◽  
Particle Size ◽  
Temperature Profile ◽  
Energy Absorption ◽  
Carbon Particle ◽  
Carbon Particles ◽  
Solar Reactor ◽  
Simulation Results ◽  
Particle Feeding ◽  
Solar Receiver

Abstract Carbon particles can be used as catalyst in solar reactors where they serve as radiant absorbent and nucleation sites for the heterogeneous decomposition reaction. Unlike commonly used metal catalysts, carbon catalyst does not have durability problem and high cost. However, in order to achieve sustainable catalytic decomposition of feedstock over carbon catalysts at elevated temperatures, the surface area of the carbon particles must be maintained. A subsequent treatment of deactivated carbon samples with CO2 at about 1000 °C would increase the surface and would recover the original activity as catalyst. In a windowed solar reactor, carbon particles are directly exposed to the high flux irradiation providing efficient radiation heat transfer directly to the reaction site. Therefore, one of the key parameters to achieve higher conversion efficiencies in a solar reactor is the presence and transport of carbon particles. In this paper, a transient one-dimensional model is presented to describe effect of carbon particle feeding on energy transport and temperature profile of a cavity-type solar receiver. The model was developed by dividing the receiver into several control volumes and formulating energy balance equations for gas phase, particles, and cavity walls within each control volume. Monte Carlo ray tracing (MCRT) method was used to determine the solar heat absorbed by particles and cavity walls, as well as the radiative exchange between particles and cavity walls. Model accuracy was verified by experimental work using a solar receiver where carbon particles were injected uniformly. Comparison of simulation results with the experimentally measured temperatures at three different locations on cavity receiver wall showed an average deviation of 3.81%. The model was then used to study the effect of carbon particle size and feeding rate on the heat transfer, temperature profile, and energy absorption of the solar receiver. Based on the simulation results, it was found that injection of carbon particles with a size bigger than 500 µm has no significant influence on heat transfer of the system. However, by reducing the particle size lower than 500 µm, temperature uniformity and energy absorption were enhanced.

Investigation on the Combustion Rate of Carbon Particle in Pressurized Oxygen-Enriched Conditions

2011 ◽  
Vol 354-355 ◽  
pp. 380-384
Author(s):  
Chun Bo Wang ◽  
Jin Gui Sheng ◽  
Ming Lei ◽  
Jian Guo Wei ◽  
Xiao Fei Ma
Keyword(s):  
Particle Size ◽  
Combustion Rate ◽  
Carbon Particle ◽  
Enriched Environment ◽  
Carbon Particles

The combustion rates of carbon particle in pressurized oxygen-enriched environment were studied. The combustion rates of different diameter carbon particles were calculated in atmospheric as well as pressurized oxygen-enriched conditions. The effects of pressure and particle size on combustion rate of carbon particle were investigated. It shows that the combustion rate of carbon particle rise with the increase of the pressures in pressurized oxygen-enriched and pressurized air conditions. But, the combustion rate of carbon particle change little at higher pressure. When particle size increased from 50μm to 100μm，the combustion rate of carbon particle rising. When the particle size increased to 150μm, the combustion rate of carbon particle changed little.

Modeling of thermal conductivity of nanofluids considering aggregation and interfacial thermal resistance

RSC Advances ◽  
2016 ◽  
Vol 6 (5) ◽  
pp. 3571-3577 ◽  
Author(s):  
Meng Liu ◽  
Chen Ding ◽  
Jun Wang
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Thermal Resistance ◽  
Interfacial Thermal Resistance

Interfacial thermal resistance was modeled and found to have a relationship to the equivalent particle size, in terms of keeping thermal resistance constant.

An Investigation of the Distribution of Trihalomethanes Within GAC Contactors

1987 ◽  
Vol 22 (3) ◽  
pp. 412-426
Author(s):  
R.C. Andrews ◽  
P.M. Huck ◽  
L. Gammie
Keyword(s):  
Particle Size ◽  
Drinking Water ◽  
Activated Carbon ◽  
Organic Carbon ◽  
Total Organic Carbon ◽  
Carbon Particle ◽  
Pilot Scale ◽  
Carbon Particles ◽  
Enhanced Adsorption ◽  
Different Sources

Abstract This study examined the loading distribution of trihalomethanes and total organic carbon within pilot scale granular activated carbon (GAC) contactors receiving finished drinking water and operating in the downflow mode. Three carbons originating from different sources were used for this comparison. Observed column loadings were compared to isotherms. As well, loadings were evaluated as a function of carbon particle size. Significantly higher loadings of trihalomethanes were found in the upper 10 cm (7%) of the GAC beds. Enhanced adsorption in this region was correlated with finer size carbon particles. Isotherms successfully predicted full bed depth trihalomethane loadings for two of the carbons but underestimated loadings in the top 10 cm. A replacement of the top 30 cm of the carbon in one of the beds resulted in a noticeable capacity increase for trihalomethanes.

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