Week 10 - Simulating Combustion of Natural Gas.

Aim:

Conduct a CFD simulation on combustion of natural gas and plot the variation of the mass fraction of the different species in the simulation using line probes at different locations of the combustor.

Solution method:

First in preparing geometry remove unwanted curves and in 'Design' tab under 'Intersect' box use 'Combine' option to combine the bodies.

Steady state analysis

Enable Axisymmetric

Enable Energy equation

And use Standard k-e equation with standard wall functions

Hybrid initialization

For parametric study create input parametres in Fuel inlet for CH4 and H2O using the drop down menu.

And create output parametrs for Soot, NOx and maximum temperature.

Boundaries:

Air inlet:

inlet velocity = 0.5m/sec

Species mass fractions:

O2: 0.23

Fuel Inlet:

Inlet velocity: 80m/sec

Species mass fractions:

CH4: 1

In Species model enable species transport.

Also enable one step soot model and enable thermal NOx and prompt NOx for NOx model

Line plots of different species at different locations along the length of the combustor

Part 2

10% H2O and 90% methane

20% H2O and 80% methane

30% H20 and 70% methae

Conclusion:

Water content	CH4	NOx	Soot	Max Temperature
10%	0.002021701	3.78E-05	4.87E-35	2290
20%	0.001102463	2.15E-05	2.35E-35	2263
30%	0.000774032	1.06E-05	2.97E-35	2229

• While increasing the percentage of water content we can observe that NOx and Soot formation is getting reduced.
• Also maximum temperature is also reducing.