A stochastic micromixing model based on the turbulent diffusion length scale

Wandel, Andrew P. (2011) A stochastic micromixing model based on the turbulent diffusion length scale. In: Australian Combustion Symposium 2011 (ACS 2011), 29 Nov-1 Dec 2011, Newcastle, Australia.

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Abstract

A new micromixing model to close probability density function (pdf) models is proposed. The model is based on the proposition that each computational timestep, stochastic particles move within the scalar space (on average) by a distance equal to the turbulent diffusion length scale. At each timestep, the model evaluates the distance in scalar space between all particles. During the timestep, a discrete pdf is computed for the distance between unmixed particles and the cumulative integral for the mean calculated. A filter is applied to retain the lower portion of the distance domain so that the cumulative integral is equal to the average diffusion length required to decrease the scalar variance. A sample (a pair of particles) is chosen from this filtered part of the domain and the particles mixed using Modified Curl’s model. The complete interparticle-distance pdf is re-evaluated for each pair to ensure that there is sufficient capacity to mix to meet the variance decay requirements. Preliminary tests show that this model obeys several fundamental properties required of micromixing models, including conservation, correct decay of variance and relaxation to Gaussian pdf.


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Item Type: Conference or Workshop Item (Commonwealth Reporting Category E) (Paper)
Refereed: Yes
Item Status: Live Archive
Additional Information: No evidence of copyright restrictions preventing deposit.
Depositing User: Dr Andrew Wandel
Faculty / Department / School: Historic - Faculty of Engineering and Surveying - Department of Mechanical and Mechatronic Engineering
Date Deposited: 30 May 2012 06:25
Last Modified: 12 Aug 2014 04:22
Uncontrolled Keywords: micromixing model; diffusion length; stochastic particles
Fields of Research (FOR2008): 09 Engineering > 0913 Mechanical Engineering > 091305 Energy Generation, Conversion and Storage Engineering
09 Engineering > 0915 Interdisciplinary Engineering > 091508 Turbulent Flows
09 Engineering > 0915 Interdisciplinary Engineering > 091501 Computational Fluid Dynamics
09 Engineering > 0915 Interdisciplinary Engineering > 091505 Heat and Mass Transfer Operations
Socio-Economic Objective (SEO2008): B Economic Development > 85 Energy > 8599 Other Energy > 859999 Energy not elsewhere classified
URI: http://eprints.usq.edu.au/id/eprint/20402

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