Multiscale Modeling and Simulation of Heat Transfer between Alumina Nanoparticles and Helium Gas

Kulkarni, Prasanna; Thoudam, Jyotishraj; Doiphode, Milind; Sundaram, Dilip Srinivas

doi:10.1016/j.ijheatmasstransfer.2020.119806

Cited by 3 publications

(8 citation statements)

References 18 publications

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“…The particle size varies in the range 25–160 nm, and the pressure and temperature of the nitrogen gas are taken to be 2 atm and 300 K, respectively. The time evolution of the particle temperature is obtained using the following particle energy balance equation: , ρ normalp c normalp π d normalp 3 6 normald T normalp normald t = prefix− q̇ cond − q̇ rad q̇ cond = α normalE π d normalp 2 p normalg c normalg 8 T δ γ + 1 γ − 1 ( T p − T δ ) q̇ rad = ϵ A σ ( T p 4 − T g 4 ) q̇…”

Section: Methodsmentioning

confidence: 99%

“…In addition, the particle energy balance is solved to compute the evolution of temperature of particle of average size ( T 66nm ) for comparison. This is described in detail in our previous works. , The initial particle temperature is taken to be the first experimentally measured temperature data after laser turn-off …”

Section: Methodsmentioning

confidence: 99%

“…= [ ] = r r r r S e e e e (12) where ω 1 and ω 2 are the angular velocity values sampled from the Maxwell−Boltzmann distribution. Using these new vectors, which are defined with respect to the crystal coordinates, the velocity to be assigned to each nitrogen atom is given by…”

Section: Synthesis Of Diatomic Gas Atommentioning

confidence: 99%

“…As a result, the oxide–gas interactions are also relevant to the heat transfer process during ignition and combustion of nanoaluminum particles. Unfortunately, the EAC data set for alumina is also not well established; prior studies , have considered only noble gases.…”

Section: Introductionmentioning

confidence: 99%

“…As a result, the oxide−gas interactions are also relevant to the heat transfer process during ignition and combustion of nanoaluminum particles. Unfortunately, the EAC data set for alumina is also not well established; prior studies 12,13 have considered only noble gases. Combustion studies involve highly nonequilibrium conditions, and most of the oxidizing gases are either diatomic or polyatomic in nature, such as oxygen, nitrogen, water vapor, and carbon dioxide.…”

Section: Introductionmentioning

confidence: 99%

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Dynamics of Energy Transfer between Nanoscale Aluminum/Aluminum Oxide Particles and Nitrogen Gas in the Noncontinuum Regime

Thoudam,

Bayad,

Sundaram

2024

J. Phys. Chem. C

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The dynamics of energy transfer between aluminum/aluminum oxide nanoparticles and nitrogen gas in the noncontinuum regime is investigated using a multiscale modeling framework. Density functional theory (DFT) computations are first performed to compute adsorption energies of nitrogen gas for aluminum and α-alumina slabs. The DFT adsorption energy data set is used to develop pair potentials for gas− surface interactions. Using the developed pair potentials, classical molecular dynamics (MD) simulations are conducted to compute the energy accommodation coefficients (EACs) for a broad range of slab temperatures, covering both thermodynamic phases of the slab. All EAC components jumped abruptly upon melting of the slab, except for the rotational EAC component of the aluminum−nitrogen system. This is attributed to the activation of low frequency lattice vibration modes and roughening of the surface of the slab upon melting. Several numerical experiments are conducted to explore the effects of the mass ratio, gas-surface well depth, and temperature on rotational EAC. A 1D collision model is also developed to explain the rotational EAC trends. It is discovered that the magnitude of rotational EAC is a function of the extent of asynchrony between the reversal of directions of rotational and translational motions of the gas molecule and phase lag between translational motions of solid atoms and gas molecules during scattering. Larger asynchrony and phase lag resulted in higher rotational EAC values. Finally, the MD-derived EACs are used as inputs to the transition regime heat transfer model to simulate the cooling of nanoalumina powder in a nitrogen gas environment. Favorable agreement with the experimental data is achieved.

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