Simulating Combustion of Natural Gas.

AIM: To simulate the combustion of Natural gas on a combustor model.

OBJECTIVE:

Part I

Perform a combustion simulation on a combustor model and plot the variation of the mass fraction of CO₂, H₂O,CH₄, N₂, O₂, NOx emissions and soot formation in the simulation.

Part II

Check the effect of add water content in fuel from 5% to 30% by mole.

THEORY:

Combustion is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke.

PROCEDURE:

Geometry: The combustor model was imported to SpaceClaim and combined to form a single object. Planes were created to obtain the 2-D geometry.

Mesh:

Body sizing = 1 mm

Edge sizing = 1 mm

Setup and solution:

Part I

Part II

Case	CH4 content by mole (%)	H2O content by mole (%)
Case 1	95	5
Case 2	90	10
Case 3	85	15
Case 4	80	20
Case 5	75	25
Case 6	70	30

Results:

Part I

Residuals

Temperature contour

Location of line probes

Mass fraction of pollutant NO

Mass fraction of Soot

Mass fraction of CH₄

Mass fraction of CO₂

Mass fraction of O₂

Mass fraction of H₂O

Mass fraction of N₂

Part II

Case 1

Temperature contour

Location of line probes

Mass fraction of pollutant NO

Mass fractiom of Soot

Mass fraction of CH₄

Mass fraction of CO₂

Mass fraction of O₂

Mass fraction of H₂O

Mass fraction of N₂

Case 2

Temperature contour

Location of line probes

Mass fraction of pollutant NO

Mass fractiom of Soot

Mass fraction of CH₄

Mass fraction of CO₂

Mass fraction of O₂

Mass fraction of H₂O

Mass fraction of N₂

Case 3

Temperature contour

Location of line probes

Mass fraction of pollutant NO

Mass fractiom of Soot

Mass fraction of CH₄

Mass fraction of CO₂

Mass fraction of O₂

Mass fraction of H₂O

Mass fraction of N₂

Case 4

Temperature contour

Location of line probes

Mass fraction of pollutant NO

Mass fractiom of Soot

Mass fraction of CH₄

Mass fraction of CO₂

Mass fraction of O₂

Mass fraction of H₂O

Mass fraction of N₂

Case 5

Temperature contour

Location of line probes

Mass fraction of pollutant NO

Mass fractiom of Soot

Mass fraction of CH₄

Mass fraction of CO₂

Mass fraction of O₂

Mass fraction of H₂O

Mass fraction of N₂

Case 6

Temperature contour

Location of line probes

Mass fraction of pollutant NO

Mass fractiom of Soot

Mass fraction of CH₄

Mass fraction of CO₂

Mass fraction of O₂

Mass fraction of H₂O

Mass fraction of N₂

OBSERVATION:

Part II

Side by side comparison:

Mass fraction of pollutant NO

Mass fraction of Soot

Mass fraction of CH₄

Mass fraction of CO₂

Mass fraction of O₂

Mass fraction of H₂O

Mass fraction of N₂

CONCLUSION:

1. The addition of water (H₂O) decreases the mass fraction of pollutant NO and Soot to a significant level.
2. Variation in mass fraction of N₂ were not observed.
3. Mass fraction of CO₂ also decreases due to addition of water (H₂O).