Week 10 - Simulating Combustion of Natural Gas.

Aim: To perform a combustion simulation on the combustor model and plot the variation of the mass fraction of the different species in the simulation.

Objective:

Part 1

1. To perform a combustion simulation and plot the variation of mass fraction of different species in the simulation using line probe at different
2. setup NOx and soot model to observe NOx emissions and soot

Part 2

1. Add water content in the fuel from 5% to 30% by mole.

Introduction

Combustion or burning is a high-temperature exothermic redox chemical reaction between a fuel and oxygen. After combustion it produces CO2,H2O and heat energy.

fuel+oxygen → water + carbon dioxide + heat energy

For Example,

CH4 + O2 → H2O + Co2 + Heat

Use of combustion reaction

• It is used in the carbon black formation industry.
• It is also used in our daily life while using LPG stove.
• This reaction is used in so many industries like thermal power plant, urea plant etc.

Geometry

Import geometry in SpaceClaim.

• now select volumes of each component and combine.

• now split the body and copy its geometry as given below.

• inlet view

• Meshing
• generate mesh

• named selections

• setup
• general setup
• Solver type: Pressure based Velocity formulation: Absolute time: Steady
• 2D space: Axisymmetric
• Energy: Enabled

• viscous model: K-epsilon, standard model with standard wall function.

• Species
• Model: Species transport
• Reactions: Volumetric
• Mixture material: methane-air
• Turbulence-Chemistry Interaction: Eddy-Dissipation

• initialization: Hybrid initialization
• create contour for the temperature.
• run calculation

Part a )

• To perform a combustion simulation and plot the variation of mass fraction of different species in the simulation using line probe at different
• Setup NOx and soot model to observe NOx emissions and soot

Residuals:

Temperature:

Nox

Soot

Ch4

Co2

H2o

N2

o2

Part B)

1. Add water content in the fuel from 5% to 30% by mole.

1)5% of H2O

Residuals

Nox

Soot

Ch4

Co2

h2o

n2

o2

2)10% of H2O

Residuals:

Nox

Soot

Ch4

Co2

H2o

N2

o2

3)15% H2O

Residuals

Nox

Soot

Ch4

Co2

h2o

N2

o2

4)20% of H2O

Residuals

Nox

Soot

ch4

Co2

H2o

o2

n2

5)25% of H2O

Residuals

Nox

Soot

Ch4

Co2

h2o

N2

o2

6)30% of H2O

Residual

Nox

Soot

Ch4

co2

H2o

N2

o2

Conclusion

• From the above results and plots we can conclude that the amount of carbon dioxide and water increases as combustion proceeds.
• Heat is released during the combustion process.
• The amount of Nitrogen going as almost same as the amount of nitrogen coming out in all the cases.