combustion

ANS 1: Types of combustion simulation are :

Based on mixing :

1. Non premixed combustion : Here the fuel and the oxidizer enter the reaction zone in different streams . Eg. Diesel internal combustion
2. Pre mixed combustion : Here the reactants are mixed at molecular level before burning.
3. Partially pre mixed combustion : This is based on the non pre mixed combustion model described in pre mixed combustion.

Based on phase :

1. Volumetric reactions : When combustion is taking place in fluid phase.
2. Surface reactions : When combustion is taking place on walll.
3. Lagrangian phase : When combustion is taking place in lagrangian phase.

ANS 2 :

# GEOMETRY

We will be using the 2D geometry.

# MESH

number of elements : 67422

size of elements : 1 mm

capture proximity : yes

# FLUENT :

PHYSICS :

1. steady state
2. axisymmetric
3. pressure based
4. absolute velocity
5. boundary conditions:

air inlet :

velocity : 0.5 m/s

temperature : 300 K

species mass fraction : o2 : 0.23

fuel inlet :

velocity : 80 m/s

temperature : 300 K

species mass fraction : Ch4 : 0.23

6. k epsilon model

7. species model :

species transport

8. reactions:

volumetric

9. mixture property :

methane - air

10. turbulence chemistry interaction :

eddy - dissipation

11. inlet diffusion

12. diffusion energy source

13. hybrid initialization.

14. number of iterations: 1500

RESIDUALS:

# POST RESULTS:

TEMPERATURE

CH4 MASS FRACTION

CO2 MASS FRACTION

H2O MASS FRACTION

N2 MASS FRACTION

O2 MASS FRACTION

# MASS FRACTION CHARTS

ch4 mass fraction

c02 mass fraction

h2o mass fraction

n2 mass fraction

02 mass fraction

here we see that the (nox) formation is not seen as the (nox) formation should take place with the mixing of air (o2) with the nitrogen in the air at high temperatures.