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Predictions of NOx and Soot Emissions in Converging and Diverging Ducts

Journal Name:

  • International Journal of Science and Engineering Investigations

Publication Year:

  • 2012

Key Words:

Author NameUniversity of Author
Abstract (2. Language): 
The influences of air preheating and diverging angle on combustion characteristics, NOx and Soot emission in the converging and diverging ducts are studied with numerical simulation. The differential equations in the Von Misses coordinate system are transformed to a cross-stream coordinate system to be able to concentrate more grid lines near wall boundaries. A marching integration solution procedure employing the TDMA is used to solve the discretized equations. In this system, by the use of a general variable, the mass, momentum, energy, and chemical species conservation equations have been written in a total form. The nature of the governing differential equation is parabolic. Also, the considered flow in this research is an incompressible flow with a compressible fluid, which its Mach numbers are less than 0.3 and it has high Peclet number. The flow behavior in the vicinity of the walls is measured through utilizing the wall function method. The considered turbulence model is the Prandtl Mixing Length method. Modeling the combustion process, in other words, measuring the amount of fuel consumption and the energy released as a result of combustion process is done by the use of Arrhenius and Eddy Dissipation method. Thermal mechanism has been utilized for modeling the process of forming the nitrogen oxides. Khan and Greeves model is used for modeling the process of Soot formation. Finite difference method and Genmix numerical code are used for numerical solution of equations. Our results indicate the important influence of the limiting diverging angle of diffuser on the coefficient of recovering of pressure. By air preheating, emission of pollutants increased. Also, the converging and diverging effect of duct on its output behavior have been indicated.
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  • 8
46-53
  • English

REFERENCES

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International Journal of Science and Engineering Investigations, Volume 1, Issue 8, September 2012 53
www.IJSEI.com Paper ID: 10812-10
ISSN: 2251-8843
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