2. Stochiometry of Real Combustion P M V Subbarao Professor Mechanical Engineering Department A First Step to Understand &Control Rate of Heat Release ….

3. Heat Addition Process of An Engine Cycle What is the optimal air/fuel ratio for Better HR ? What Parameters control the HRR ?

4. Structure of Ford Research simulation. Thermo Chemical Equilibrium

5. Fuel Model Ultimate Analysis of fuel: Gravimetric C : 84 -- 87% ; H : 11 -- 16% ; O : 0.3 -- 1.8% ; N : 0.1 -- 1.5% ; S : 0.1 -- 3% Percentage of carbon : x --- Number of moles, X = x/12 Percentage of hydrogen : y --- Number of atomic moles, Y = y/1 Percentage of oxygen: k --- Number of atomic moles, K = k/16 Percentage of sulfur: z – Number of atomic moles, Z = z/32 Equivalent chemical formula : C X H Y S Z O K Equivalent Molecular weight : 100 gms. Liquid and gaseous fuels generally have very little sulfur, oxygen and moisture. Generally popular chemical formulae: C X H Y

6. Ideal combustion C X H Y + 4.773 (X+Y/4) AIR → P CO 2 +Q H 2 O + R N 2 Molecular weight of fuel : Homogeneous Mixture model for Air: Molecular weight of Air : Air-fuel Ratio:

7. Equivalence Ratio The equivalence ratio of a system is defined as the ratio as the ratio of the actual fuel/air ratio to the stoichiometric ratio. Mathematically

8. Universal Law for Completion of Reaction End of Reaction for an adiabatic system:

10. Theoretical Prediction of Combustion Products: Pure Iso- Octane @ 5.0 MPa

13. Equilibrium Products at High Pressure 30 atm :Octane

16. Theoretical Prediction of Combustion Products: Pure Cetane

17. Real Combustion & Model Testing

18. Results of Model Testing. For a given fuel and required steam conditions. Optimum composition of Exhaust Gas. Optimum air flow rate. Optimum fuel flow rate. Optimum combustion configuration!!! Molar Analysis of Dry Exhaust Products: Mole fraction of CO 2 : x 1 Mole fraction of CO : x 2 Mole fraction of O 2 : x 4 Mole fraction of N 2 : x 5