ME 569

HW #2

Due 9-23-96

In the book: Chap 4, #4,5,7

Chap 5 #1,3,4,8

1) Consider the constant pressure (1.0 MPa) combustion of a =0.95 propane - air mixture with residual gases added prior to the combustor. The residual gases can be considered to be the ideal products of =0.95 propane combustion.

A) Plot the T_ad and the equilibrium concentrations [kmol/m³] of [O₂], [O], [OH], [H] and [NO] as a function of the volume fraction of residuals (0-30%)

{Hints:

1) For simplicity do not consider the equilibrium reactions in the adiabatic flame temperature calculation

2) The chemical reaction with residuals is:

C₃H₈ + a(O₂ + 3.76 N₂) + R(bCO₂ + cH₂O + dO₂ + eN₂) ---> products

where b, c, d, e are determined from the ideal combustion products without exhaust gas recirculation.

}

B) Using the extended Zeldovich mechanism plot [NO]/[NO]_eq vs time for residual concentrations of 0,5,10,20, and 30%.

extra credit:

redo part b) for 10% (volume) recirculation but relax the two assumptions of the hint.