Challenge on Combustion
Aim: To perform a combustion simulation on the combustor model and plot the variation of the mass fraction of the different species’
Software Used: ANSYS Fluent 2020 R1
Objectives:
Part 1: We have to do the simulation and show the plots using line probes at different locations of the combustor. We need to plot for CO2, H2O, CH4, N2, O2, NOx emissions & Soot formation.
Part 2: In this part, you need to add the water content in the fuel from 5% to 30% by mole and observe the effect of it on the results.
Geometrical Setup:
The model was given in 3d mode. Basically we have to turn 3d model to 2d surface to do simulation. Here I decided to make a 2d model by myself for the analysis.
Close up:
Meshing:
The Method here used is All triangles method.
Element Size: 5 mm
Capture Proximity is on and num cells across the gap is 3.
Nodes: 19968
Elements: 39013
Mesh-
Named Selections:
PART 1:
Case Setup:
- Solver -
1.Type: Pressure-based
2. Velocity Formulation: absolute
3. Time: Steady
4. 2d Space: Axisymmetric
- Viscous model - K-epsilon Model, standard, standard wall functions.
- Energy equation is ON.
- Species model:
1. Model: Species Transport
2. Reactions: Volumetric
3. Options: Inlet Diffusion and Diffusion Energy Source
4. Mixture Material: Methane-air
5. Turbulence-Chemistry Interaction: Eddy Dissipation
- NOx model is ON.
- Soot One-step model is ON.
- Boundary Conditions:
1. Air-inlet :
2. Fuel-Inlet:
- Hybrid Initialization is done.
- The contour of static temperature is created and animation is done.
- At 1000 number of iterations, calculations are done.
Residual Plot:
Static Temperature Contour:
RESULTS:
Volume rendering:
The plane is created in which mass fraction and their respective charts are prepared.
Line probes are created at 6 different locations: 0.3 m, 0.6 m, 0.9 m, 1.2 m, 1.5 m, 1.8 m.
Mass Fraction and chart Of Eddy Viscosity:
Mass Fraction and Chart of CH4:
Mass Fraction and chart of Co2:
Mass Fraction and chart of H2O:
Mass Fraction and chart of N2:
Mass Fraction and chart of O2:
Mass Fraction and chart of NO Pollutant Emission:
Mass Fraction and chart of Soot Formation:
PART 2:
Case Setup:
- Solver -
1.Type: Pressure-based
2. Velocity Formulation: absolute
3. Time: Steady
4. 2d Space: Axisymmetric
- Viscous model - K-epsilon Model, standard, standard wall functions.
- Energy equation is ON.
- Species model:
1. Model: Species Transport
2. Reactions: Volumetric
3. Options: Inlet Diffusion and Diffusion Energy Source
4. Mixture Material: Methane-air-2step
5. Turbulence-Chemistry Interaction: Eddy Dissipation
- NOx model is ON.
- Soot One-step model is ON.
- Boundary Conditions:
1. Air-inlet :
2. Fuel-Inlet:
(a) 5% of H2O:
Fuel Inlet- Species:
Residual Plot:
The contour of Static temperature:
Volume Rendering:
Mass Fraction and chart of Eddy Viscosity:
Mass Fraction and chart of CH4:
Mass Fraction and Chart of Co2:
Mass Fraction and chart of H2O:
Mass Fraction and chart of N2:
Mass Fraction and chart of O2:
Mass fraction and chart of Pollutant No:
Mass Fraction and chart of Soot Formation:
(b) 15% of water content:
Residual plot:
The contour of Static Temperature:
Volume Rendering:
Mass Fraction and chart of Eddy Viscosity:
Mass Fraction and Chart of CH4:
Mass Fraction and Chart of CO2:
Mass Fraction and Chart of H2O:
Mass Fraction and Chart of N2:
:
Mass Fraction and Chart of O2:
Mass Fraction and Chart of Pollutant NO:
Mass Fraction and Chart of Soot Formation:
(c) 30% of water content:
Residual plot:
The contour of static Temperature:
Volume Rendering:
Mass Fraction and chart of Eddy viscosity:
Mass Fraction and Chart of CH4:
Mass Fraction and Chart of CO2:
Mass Fraction and Chart of H2O:
Mass Fraction and Chart of N2:
Mass Fraction and Chart of O2:
Mass Fraction and Chart of Pollutant No:
Mass Fraction and Chart of Soot Formation:
ANIMATIONS:
PART 1-
PART 2:
(a) 5% of water content:
(b) 15% of water content:
(c) 30% of water content:
Observations:
| Water Content(%) | NOx values |
| 0 | 0.00832751 |
| 5 | 0.00638322 |
| 15 | 0.00217055 |
| 30 | 0.0020754 |
Conclusions:
As we can see that NOx have harmful effects on the environment and humans. The stringent government norms also demand the least formation of Nox and soot so we added some percentage of water content in the fuel such as 5%,15% and 30%. By the above results, we can notice that when the water contents are added to the fuel the NOx pollutant is decreasing which is good. From this, we can tell there is efficient combustion happened. After adding water in the fuel temperature of the combustor also get decreased when the water content is increased.
The maximum temperature obtained for 5%, 15%, 30% are 2454.74K, 2289.98K, 2239.92K respectively.