Author: N. Al-Abbadi
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: N. Al-Abbadi
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: National Aeronautics and Space Adm Nasa
Publisher: Independently Published
ISBN: 9781731360588
Category : Science
Languages : en
Pages : 160

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The current Final Report contains results of the study which was performed in Scientific Research Center 'ECOLEN' (Moscow, Russia). The study concerns the development and verification of non-expensive approach for modeling of supersonic turbulent diffusion flames based on flamelet consideration of the chemistry/turbulence interaction (FL approach). Research work included: development of the approach and CFD tests of the flamelet model for supersonic jet flames; development of the simplified procedure for solution of the flamelet equations based on partial equilibrium chemistry assumption; study of the flame ignition/extinction predictions provided by flamelet model. The performed investigation demonstrated that FL approach allowed to describe satisfactory main features of supersonic H 2/air jet flames. Model demonstrated also high capabilities for reduction of the computational expenses in CFD modeling of the supersonic flames taking into account detailed oxidation chemistry. However, some disadvantages and restrictions of the existing version of approach were found in this study. They were: (1) inaccuracy in predictions of the passive scalar statistics by our turbulence model for one of the considered test cases; and (2) applicability of the available version of the flamelet model to flames without large ignition delay distance only. Based on the results of the performed investigation, we formulated and submitted to the National Aeronautics and Space Administration our Project Proposal for the next step research directed toward further improvement of the FL approach. Secundov, A. and Bezgin, L. and Buriko, Yu. and Guskov, O. and Kopchenov, V. and Laskin, I. and Lomkov, K. and Tshepin, S. and Volkov, D. and Zaitsev, S. TURBULENT COMBUSTION; TURBULENT DIFFUSION; DIFFUSION FLAMES; SUPERSONIC JET FLOW; COMPUTATIONAL FLUID DYNAMICS; TURBULENCE MODELS; CHEMICAL REACTIONS; IGNITION; EXTINCTION; GAS MIXTURES; AIR JETS; OXIDATION; DIFFERENTIAL EQUATIONS; MATHEMATICAL MODEL...

Author: Andreas Kronenburg
Publisher:
ISBN:
Category : Air
Languages : en
Pages : 446

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Author: Sylvie Honnet
Publisher: Cuvillier Verlag
ISBN: 386727391X
Category :
Languages : en
Pages : 147

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Author:
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 538

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Author: Bifen Wu
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Buoyancy-driven diffusion flames have been widely studied as a canonical fire configuration due to practical and scientific interests. Numerical investigations are conducted in this dissertation to improve understandings of interactions and couplings among turbulence, chemistry, soot, and multiphase radiation in buoyancy-driven diffusion flames. A high-fidelity modeling framework based on OpenFOAM-5.x, including detailed models for chemistry, radiation, and soot, is developed to improve the numerical accuracy and the computational efficiency with scale-resolved simulations. A Monte Carlo ray tracing (MCRT) based radiation solver coupled with line-by-line databases is developed to describe gas and soot radiation. Detailed and efficient radiation models for water mists are developed and coupled with the MCRT solver. An adaptive hybrid integration chemistry solver is implemented to speed up finite-rate chemistry integration. A semi-empirical two-equation soot model is incorporated to describe soot dynamics. The developed multi-physical platform is systematically verified through a series of combustion-radiation systems including a laminar ethylene diffusion flame and four laminar methane diffusion flames with good agreement. The developed platform is subsequently employed to investigate a laboratory-scale turbulent pool fire. Good agreement with experiments on radiative heat fluxes, and with theories on flame temperature, velocity and puffing frequency, is achieved. Detailed investigations on interactions among chemistry, soot, radiation, and turbulence are performed to gain physical insights on modeling chemistry, soot and radiation. Drawn on the database from high-fidelity pool fire simulations, three physics-based reduced-order models including a flamelet model considering re-absorption, an optimized two-step mechanism for chemistry, and a simple soot model based on the laminar smoke point concept, are developed. Encouraging results are obtained using the reduced-order models with considerable savings in computational cost. Finally, to investigate radiative attenuation of water mists in fire suppression, a radiation model considering anisotropic scattering for water mists is developed and validated against theoretical values, and is adopted to obtain benchmark results for development of reduced-order radiation models.

Author:
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 728

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Author: Naif Mohammed Al-Abbadi
Publisher:
ISBN:
Category :
Languages : en
Pages : 426

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Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 984

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