An experimental study of a reactive plume in grid turbulence
Brown, R.J. & Bilger, R.W. (1996) An experimental study of a reactive plume in grid turbulence. Journal of Fluid Mechanics, 312, pp. 373-407.
Experimental results for a reactive non-buoyant plume of nitric oxide (NO) in a turbulent grid flow doped with ozone (O3) are presented. The Damkohler number (Nd) for the experiment is of order unity indicating the turbulence and chemistry have similar timescales and both affect the chemical reaction rate. Continuous measurements of two components of velocity using hot-wire anemometry and the two reactants using chemiluminescent analysers have been made. A spatial resolution for the reactants of four Kolmogorov scales has been possible because of the novel design of the experiment. Measurements at this resolution for a reactive plume are not found in the literature. The experiment has been conducted relatively close to the grid in the region where self-similarity of the plume has not yet developed. Statistics of a conserved scalar, deduced from both reactive and non-reactive scalars by conserved scalar theory, are used to establish the mixing field of the plume, which is found to be consistent with theoretical considerations and with those found by other investigators in non-reative flows. Where appropriate the reactive species means and higher moments, probability density functions, joint statistics and spectra are compared with their respective frozen, equilibrium and reaction-dominated limits deduced from conserved scalar theory. The theoretical limits bracket reactive scalar statistics where this should be so according to conserved scalar theory. Both reactants approach their equilibrium limits with greater distance downstream. In the region of measurement, the plume reactant behaves as the reactant not in excess and the ambient reactant behaves as the reactant in excess. The reactant covariance lies outside its frozen and equilibrium limits for this value of Vd. The reaction rate closure of Toor (1969) is compared with the measured reaction rate. The gradient model is used to obtain turbulent diffusivities from turbulent fluxes. Diffusivity of a non-reactive scalar is found to be close to that measured in non-reactive flows by others.
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|Item Type:||Journal Article|
|Keywords:||Damkohler Number, Reactive Plumes, Grid Turbulence, Reaction Rate Closure, Turbulence Chemistry Interaction|
|Subjects:||Australian and New Zealand Standard Research Classification > CHEMICAL SCIENCE (030000) > THEORETICAL AND COMPUTATIONAL CHEMISTRY (030700) > Reaction Kinetics and Dynamics (030703)
Australian and New Zealand Standard Research Classification > EARTH SCIENCES (040000) > ATMOSPHERIC SCIENCES (040100) > Atmospheric Sciences not elsewhere classified (040199)
Australian and New Zealand Standard Research Classification > ENGINEERING (090000) > INTERDISCIPLINARY ENGINEERING (091500) > Turbulent Flows (091508)
|Divisions:||Past > QUT Faculties & Divisions > Faculty of Built Environment and Engineering
Past > Schools > School of Engineering Systems
|Copyright Owner:||Copyright 1996 Cambridge University Press|
|Deposited On:||01 Dec 2011 22:56|
|Last Modified:||20 Oct 2012 00:42|
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