Week 10 - Simulating Combustion of Natural Gas.

PROJECT REPORT

OBJECTIVE:

Part I

Performing combustion simulation for natural gas and plotting the graph and contours for the mass fraction of all the species involved in the combustion and Soot formation And No Pollutant

Part II

As we know Formation of Soot and No Pollutant is not good for environment, so we can control its formation by adding H2O in the fuel so in this part we are going to add H2O as follow from 5% to 30% so check the difference

GEOMETRY:

Given Geometry:

We need to converet It in 2D

As It is in 3 Phases we have to use split command and at the end to merge all the phases we have to use merge command

Final Geometry

MESH:

Mesh element size is 5mm and its simple triangular mesh pattern

Total no. of nods are 12948 nos

This is how my name selection looks like

Fluent Setup:

Solver: Pressure base solver

Steady state solver

Material selection:

METHANE-Air for fuel without eater

And Methane-Air 2-step for fuel with water

Setting up Physics:

Select K-epsilon, Terbulant model we are using turbulent model because in species model we are using eddy base so to make the fule ignite we have to use tebulant model

We need to add the details about the species in boundary condition

Boundary condition:

Air Inlet- Velocity = 0.5m/s

Temperature = 300K

Species Mass Fraction O2 = 0.23

Fuel Inlet- Velocity = 18m/s

Temperature= 300K

Species = CH4 = 1

Outlet: Pressure outlet = 0

Enable Thermal NOx model and SOOT model from the more option in Fluent

SOLVING:

Part I:

In this case the species configuration in fuel is CH4 = 1

Residuals:

Following are the plot for CO2, H2O, C, N2, O2, NOx emission and soot formation

For checking the flow of all this species, we have to add line prob in the process like this-

Distance of the line probes are with the increment of 0.5m

Starting from 0.5m

• O2

• CH4

• CO

• CO2

• H2O

• N2

• SOOT

• POLUTANT NO

Now, As we can see the Soot and NOx is forming at large scale which is not good now lets check by adding water in Part II

Part II

• H2O = 5%

In order to make H2O 5% in fuel we need to go in species and change the configuration CH4 = 0.95 and H2O = 0.05

Results:

SOOT:

NOx Polutant:

If we compare it with the Previous simulation defeatedly the formation of soot and NOx is low in this case

• H2O = 20%

NOx Polutant

Soot

• H2O = 30%

Soot

NOx pollutant

CONCLUSION:

• The level of Co2,N2 and maximum temperature obtain are not much caried
• As the water percentage in increasing in the fuel the NOx emission is decreased
• As water percentage increases soot emission is also decreased