A Numerical Study of Combined Rate, Size and Thermal Effects on the Responses of Ultrananocrystalline Diamond

2007 ◽  
pp. 621-624
Author(s):  
Lu Ming Shen ◽  
Zhen Chen
Keyword(s):  
Thermal Effects ◽  
Numerical Study ◽  
Ultrananocrystalline Diamond

A Numerical Study of Combined Rate, Size and Thermal Effects on the Responses of Ultrananocrystalline Diamond

2007 ◽  
Vol 334-335 ◽  
pp. 621-624 ◽  
Author(s):  
Lu Ming Shen ◽  
Zhen Chen
Keyword(s):  
Working Conditions ◽  
Material Properties ◽  
Thermal Effects ◽  
Loading Rate ◽  
Numerical Study ◽  
Kinetic Monte Carlo ◽  
Tensile Loading ◽  
Md Simulations ◽  
Grain Sizes ◽  
Ultrananocrystalline Diamond

To better understand the responses of ultrananocrystalline diamond (UNCD) under extreme working conditions, a numerical study is performed to investigate the size, loading rate and thermal effects on the material properties of UNCD films. A combined kinetic Monte Carlo (KMC) and molecular dynamics (MD) method is first applied to simulate the growth of polycrystalline UNCD films. The responses of the resulting UNCD films with various grain sizes are then investigated by applying displacement–controlled tensile loading with different rates and temperatures in the MD simulations. The preliminary results presented in this paper provide a better understanding of the combined size, rate and thermal effects on the material properties of UNCD.

Numerical Study of the Thermal Effects on the Centrifugal Instability

2006 ◽  
Vol 30 (6) ◽  
pp. 578-586 ◽  
Author(s):  
Jong-Yeon Hwang ◽  
Innocent Mutabazi ◽  
Sung-Su Lee ◽  
Dong-Hyeog Yoon ◽  
Kyung-Soo Yang
Keyword(s):  
Thermal Effects ◽  
Numerical Study ◽  
Centrifugal Instability

Numerical Study of Cavitation in Cryogenic Fluids

2005 ◽  
Vol 127 (2) ◽  
pp. 267-281 ◽  
Author(s):  
Ashvin Hosangadi ◽  
Vineet Ahuja
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Critical Temperature ◽  
Thermal Effects ◽  
Free Stream ◽  
Numerical Study ◽  
Stream Velocity ◽  
Transfer Model ◽  
Cryogenic Fluids ◽  
Parametric Studies

Numerical simulations of cavitation in liquid nitrogen and liquid hydrogen are presented; they represent a broader class of problems where the fluid is operating close to its critical temperature and thermal effects of cavitation are important. A compressible, multiphase formulation that accounts for the energy balance and variable thermodynamic properties of the fluid is described. Fundamental changes in the physical characteristics of the cavity when thermal effects become significant are identified; the cavity becomes more porous, the interface less distinct, and it shows increased spreading while getting shorter in length. The heat transfer model postulated in variants of the B-factor theory, where viscous thermal diffusion at the vapor-liquid interface governs the vaporization, is shown to be a poor approximation for cryogenic fluids. In contrast the results presented here indicate that the cavity is sustained by mass directly convecting into it and vaporization occurring as the liquid crosses the cavity interface. Parametric studies for flow over a hydrofoil are presented and compared with experimental data of Hord (1973, “Cavitation in Liquid Cryogens II—Hydrofoil,” NASA CR-2156); free-stream velocity is shown to be an independent parameter that affects the level of thermal depression.

scholarly journals BLEVE Fireball Effects in a Gas Industry: A Numerical Modeling Applied to the Case of an Algeria Gas Industry

2020 ◽  
Author(s):  
Brady Manescau ◽  
Khaled Chetehouna ◽  
Ilyas Sellami ◽  
Rachid Nait-Said ◽  
Fatiha Zidani
Keyword(s):  
Numerical Modeling ◽  
Thermal Effects ◽  
Large Scale ◽  
Numerical Study ◽  
Single Step ◽  
Gas Field ◽  
Gas Industry ◽  
Eddy Simulation ◽  
Scale Experiment ◽  
Potential Damage

This chapter presents the numerical modeling of the BLEVE (Boiling Liquid Expanding Vapor Explosion) thermal effects. The goal is to highlight the possibility to use numerical data in order to estimate the potential damage that would be caused by the BLEVE, based on quantitative risk analysis (QRA). The numerical modeling is carried out using the computational fluid dynamics (CFD) code Fire Dynamics Simulator (FDS) version 6. The BLEVE is defined as a fireball, and in this work, its source is modeled as a vertical release of hot fuel in a short time. Moreover, the fireball dynamics is based on a single-step combustion using an eddy dissipation concept (EDC) model coupled with the default large eddy simulation (LES) turbulence model. Fireball characteristics (diameter, height, heat flux and lifetime) issued from a large-scale experiment are used to demonstrate the ability of FDS to simulate the various steps of the BLEVE phenomenon from ignition up to total burnout. A comparison between BAM (Bundesanstalt für Materialforschung und –prüfung, Allemagne) experiment data and predictions highlights the ability of FDS to model BLEVE effects. From this, a numerical study of the thermal effects of BLEVE in the largest gas field in Algeria was carried out.

Numerical study of thermal effects in cryo-adsorptive hydrogen storage tank

2013 ◽  
Vol 5 (2) ◽  
pp. 021414 ◽  
Author(s):  
Jinsheng Xiao ◽  
Hao Yang ◽  
Pierre Bénard ◽  
Richard Chahine
Keyword(s):  
Hydrogen Storage ◽  
Thermal Effects ◽  
Storage Tank ◽  
Numerical Study

Weakly Compressible Fluid Model to Study Thermal Effects on Laser Propagating in Closed Tube

2011 ◽  
Vol 354-355 ◽  
pp. 165-169
Author(s):  
Jian Liu ◽  
Shi Qing Wang
Keyword(s):  
Compressible Fluid ◽  
Thermal Effects ◽  
Numerical Study ◽  
Fluid Model ◽  
Approximate Model ◽  
Beam Shape ◽  
Laser Propagation ◽  
Weakly Compressible ◽  
Closed Tube ◽  
Gas Medium

Analyzed the iso-pressure approximate model used in laser propagation in gas medium and pointed out its disadvantage under complex border conditions. The weakly compressible fluid model was developed which was based on the Mach uniform method introduced by Peter Wesseling. Using the weakly compressible fluid model and scalar wave equation, a numerical study was carried out for the gas thermal effects on laser propagating in a closed tube full-filled with air. The far-field beam shape at different time were obtained and compared with the experiment ones. It is shown that the weakly compressible fluid model could be well adapted for problems with complex border conditions, acute than the compressible fluid model or the iso-pressure approximate model.

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