Objectives

1. Carry out the Ansys Fluent CFD combustion tutorial with TWO changes from the instructions:

a. Use the methane-air-2step mechanism instead of the methane-air mechanism, and

b. Set under-relaxation factors for species to 0.9 instead of 0.95 & 1.0.

2. Perform the same analysis for the following conditions:

a. All inlet temperatures set to 500 K,

b. Outer-wall set to adiabatic,

c. Φ values of 0.7, 0.85 and 1.0 (which can be achieved by varying the fuel velocity/flow rate).

i. Note you will need to adjust the equivalence ratio in the prompt NO submodel too. This must match with the air-fuel ratio entering the domain.

3. Show contour plots of T, YCO and YNO on the 2D CFD plane for the Φ values given above.

4. Run the 1D Cantera flame model to obtain profile plots of T, YCO and YNO for the same conditions used in CFD. Discuss the similarities and differences between the CFD and 1D flame model under the following headings: spatial distribution of calculated variables, impact of equivalence ratio, extent of fuel-air premixing, treatment of chemical kinetics, overall accuracy.

Deliverables

You must submit a Word document containing.

- All of the required graphs in Excel, Matlab or Fluent. They must be properly captioned, use proper axis titles and legends, and employ axis limits that make sense. Make sure they are clear and easy to interpret.

- Brief discussions (1-2 lines per topic) as requested in Objective 4 above.