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Entropy Generation Minimization Concept Evaluating Mixing Efficiency Through, Variable Density, Isothermal, Free Turbulent Jet

  • Nejmiddin BoughattasEmail author
Conference paper
  • 66 Downloads
Part of the Lecture Notes in Mechanical Engineering book series (LNME)

Abstract

This paper is devoted to the numerical and theoretical study of axisymmetric variable density jet discharging into a co-flowing stream. The results reveal that kε models give satisfactory agreement with experimental data. The results show also that entropy generation due to mass transfer is very higher than that corresponds to fluid friction. In addition, it was found that Entropy Generation Minimization concept can be used as an indicator to evaluate mixing efficiency and mixedness.

Keywords

Free turbulent jet Entropy generation Mixing 

Nomenclature

C

Concentration mol·m−3

Cμ, Cε

Turbulence model constants

Cp

Specific heat. J·Kg−1·K−1

d

Nozzle diameter m

D

Mass diffusivity. m2s−1

G

Production term of k…kg·m−1·s−3

I

Mixing efficiency

k

Turbulent kinetic energy…m2·s−2

P

Pressure N·m−2

R

Ideal gas constant JKg−1K−1

r

Radial distance m

Sgen

Entropy generation rate… WK−1

\(S_{gen}^{\prime \prime \prime }\)

Local volumetric entropy generation rate Wm−3K−1

T

Temperature K

u, v

Velocity components in x, y direction ms−1

x, y

Cartesian coordinates m

Y

Mass fraction

Z

Mixture fraction

Greek symbols

ε

Dissipation rate of k m2·s−3

µ

Dynamic viscosity kg· (m·s)−1

ρ

Density kg·m−3

λ

Thermal conductivity…Wm−1k−1

σk, σε

Turbulence model constants

σθ

Schmidt or Prandtl number (0.7)

θ

Scalar variable (C-T-Y-Z)

θ’2

Scalar variance

χ

Scalar dissipation rate s−1

Subscripts

a

Air, ambient fluid

0

Nozzle condition

eff

Effective

c

Condition at the jet centreline

in

Value at the jet exit

k

Species index (propane)

t

Turbulent

Acronyms

EGM

Entropy Generation Minimization

STD

Standard

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Copyright information

© Springer Nature Switzerland AG 2020

Authors and Affiliations

  1. 1.IPEIKKairouanTunisia

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