AME 514 – Spring 2019 Homework Assignment #3
Due at 5:00 pm on Wednesday, April 3, 2019 (All Reports Must be Submitted Electronically)
Computation Assignment Using the Cantera Software Package
Compute the following freely propagating flames:
1. CH4/air, φ = 0.8, 1.0, 1.3, P = 1, 10, and 20 atm, Tu = 300 K.
2. n-C7H16/air, φ = 0.8, 1.0, 1.3, P = 1, 10, and 20 atm, Tu = 400 K.
The CH4/air flame simulations will involve the use of the USC Mech II kinetic model that is attached along with the pertinent Thermodynamic and Transport databases.
The n-C7H16/air flame simulations will involve the use of the JetSurf kinetic model that is attached along with the pertinent Thermodynamic and Transport databases.
Note that NOx chemistry has been added in both USC Mech II and JetSurf kinetic models.
Task #1:
For each flame plot the following versus spatial coordinate x (in cm).
1. The fuel and O2 mass fraction variations.
2. The O, H, and OH mass fraction variations.
3. The CO and CO2 mass fraction, as well as the heat release variations.
4. The variations of the H + O2 = OH + O and CO + OH = CO2 + H reaction rates.
Make sure that appropriate x-scale is used so that the details of the flame zone can be identified. You may consider also creating double plots or appropriately scaled plots in order to make meaningful assessments of the various processes. Please comment on the results.
Task #2:
Compare the laminar flame speeds, Suo , and mass burning rates at various equivalence ratios and pressures and carry out sensitivity analysis to identify the controlling kinetic steps. Please comment on
the results and discuss fuel effect, pressure effect, and equivalence ratio effect.
Task #3:
Compare the soot formation propensity of all flames based on the maximum mass fraction of C2H2, which is a major soot precursor. Please comment on the pressure, fuel, and equivalence ratio effect.
Task #4:
Compare the NOx formation propensity of all flames based on the maximum mass fraction of NO, and compared the relative contributions of thermal and prompt NOx mechanisms at various equivalence ratios and pressures.