Prompt Transient Heat Transfer Effects in Low-Fluence Laser Induced Incandescence

2012 ◽  
Author(s):  
F. Memarian ◽  
K. J. Daun
Keyword(s):  
Experimental Studies ◽  
Direct Simulation Monte Carlo ◽  
Recent Time ◽  
Direct Simulation ◽  
Transient Effects ◽  
Time Resolved ◽  
Laser Induced Incandescence ◽  
Simulation Monte Carlo ◽  
Heat Transfer Effects ◽  
Particle Cooling

Recent time-resolved laser-induced incandescence (TiRe-LII) experimental studies have revealed anomalies in particle cooling rates that cannot be explained using steady-state conduction models. This is the first study to use Direct Simulation Monte Carlo (DSMC) to investigate possible transient effects in heat conduction between the laser-energized particle and surrounding gas. While the DSMC results reveal an increased cooling rate shortly after the laser pulse, this effect is small relative to experimentally-observed anomalous cooling.

Gas Dynamics of Sublimed Carbon Nano-Clusters in High Fluence Time-Resolved Laser-Induced Incandescence

2013 ◽  
Author(s):  
F. Memarian ◽  
K. J. Daun
Keyword(s):  
Shock Waves ◽  
Gas Dynamics ◽  
Direct Simulation Monte Carlo ◽  
Analytical Models ◽  
High Fluence ◽  
Time Resolved ◽  
Back Flow ◽  
Model Predictions ◽  
Laser Induced Incandescence ◽  
Simulation Monte Carlo

High fluence time-resolved laser-induced incandescence (TiRe-LII) measurements show a discrepancy between experimental observations and model predictions. Several hypotheses have been proposed to explain this discrepancy, including the possibility of back flow of sublimed species and the possibility of formation of shock waves. This is the first study that uses transient Direct Simulation Monte Carlo (DSMC) to investigate the abovementioned effects in high fluence TiRe-LII. This study verifies that back flow of sublimed species occurs, and must be included in analytical models. On the other hand, shock waves were not observed for the fluences and predetermined temperature curves used in this study.

Investigation of Dynamic Near-Field Radiation Between Quantum Dots and Plasmonic Nanoparticles for Effective Tailoring of Solar Spectrum

2011 ◽  
Author(s):  
Nola Palombo ◽  
Keunhan Park
Keyword(s):  
Quantum Dots ◽  
Numerical Scheme ◽  
High Efficiency ◽  
Near Field ◽  
Experimental Studies ◽  
Solar Spectrum ◽  
Direct Simulation Monte Carlo ◽  
Direct Simulation ◽  
Field Radiation ◽  
Simulation Monte Carlo

This paper presents the theoretical and experimental studies of dynamic near-field interactions between quantum dots (QDs) and plasmonic gold nanoshell (GNS) nanoparticles suspended in an aquatic solution in attempts to effectively tailor the solar spectrum. The photoemission measurement of the CdTe QD/GNS nanofluid (1×1017 mL−1 for QDs and 5×108 mL−1 for GNSs) is amplified by 2.7 times when compared with the photoemission for QD-only solution with the same QD concentration. In order to investigate the mechanism of such enhancement, the direct simulation Monte Carlo (DSMC) numerical scheme combined with the Langevin formalism was developed. The modified DSMC can stochastically trace particle movements of QDs and GNSs in the nanofluid, suggesting that QDs within near-field of GNSs are responsible for the photoemission enhancement. The obtained results will provide the feasibility of using the dynamic near-field radiation to down-convert the solar spectrum with enhancement, which could be applied towards high-efficiency photovoltaics.

Numerical Methods for the Kinetic Theory of Fluids

2018 ◽  
Author(s):  
Sauro Succi
Keyword(s):  
Molecular Dynamics ◽  
Monte Carlo ◽  
Numerical Methods ◽  
Kinetic Theory ◽  
Computational Efficiency ◽  
Lattice Boltzmann ◽  
Direct Simulation Monte Carlo ◽  
Particle Methods ◽  
Direct Simulation ◽  
Simulation Monte Carlo

This chapter provides a bird’s eye view of the main numerical particle methods used in the kinetic theory of fluids, the main purpose being of locating Lattice Boltzmann in the broader context of computational kinetic theory. The leading numerical methods for dense and rarified fluids are Molecular Dynamics (MD) and Direct Simulation Monte Carlo (DSMC), respectively. These methods date of the mid 50s and 60s, respectively, and, ever since, they have undergone a series of impressive developments and refinements which have turned them in major tools of investigation, discovery and design. However, they are both very demanding on computational grounds, which motivates a ceaseless demand for new and improved variants aimed at enhancing their computational efficiency without losing physical fidelity and vice versa, enhance their physical fidelity without compromising computational viability.

Study on the Deposition Profile Characteristics in the Micron-Scale Trench Using Direct Simulation Monte Carlo Method

1998 ◽  
Vol 120 (2) ◽  
pp. 296-302 ◽  
Author(s):  
Masato Ikegawa ◽  
Jun’ichi Kobayashi ◽  
Morihisa Maruko
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Boundary Conditions ◽  
Gas Flow ◽  
Direct Simulation Monte Carlo ◽  
Low Pressure ◽  
Sputter Deposition ◽  
Direct Simulation ◽  
Simulation Monte Carlo ◽  
Profile Characteristics

As integrated circuits are advancing toward smaller device features, step-coverage in submicron trenches and holes in thin film deposition are becoming of concern. Deposition consists of gas flow in the vapor phase and film growth in the solid phase. A deposition profile simulator using the direct simulation Monte Carlo method has been developed to investigate deposition profile characteristics on small trenches which have nearly the same dimension as the mean free path of molecules. This simulator can be applied to several deposition processes such as sputter deposition, and atmospheric- or low-pressure chemical vapor deposition. In the case of low-pressure processes such as sputter deposition, upstream boundary conditions of the trenches can be calculated by means of rarefied gas flow analysis in the reactor. The effects of upstream boundary conditions, molecular collisions, sticking coefficients, and surface migration on deposition profiles in the trenches were clarified.

Sign in / Sign up

Export Citation Format

Share Document