Unformatted text preview: ME 312 HOMEWORK #7
Spring 2009 Due: Thursday 4 June
Final Exam: Monday 8 June 9:30 am *Assume 1 bar atmospheric pressure for all problems, unless otherwise speciﬁed. #1. Ethylene (C2H4) is burned with 200% theoretical air during a combustion process. Assuming complete
combustion and a total pressure of 120 kPa, determine a) The air-ﬁtel ratio
b)The dew-point temperature of the products. #2. Liquid propane (C3Hg) at 25 °C with 250% theoretical air enters a combustion chamber at 12 °C. The
mass ﬂow rate of the ﬁiel is 1.2 kg/min. If the combustion is complete and the exit temperature of the reaction products is 1200 K, ﬁnd
a) The rate of heat transfer from the combustion chamber in kJ/min. b) The mass ﬂow rate of the air in kg air/min #3. Benzene gas (C6H6) at 298 K is burned during a steady-ﬂow combustion process with 95% theoretical
air that enters the chamber at 298 K. If the products exit at a temperature of 1000K, determine a) The mole fraction of CO in the products b) The equivalence ratio
c) The rate of heat transfer from the combustion chamber in kJ/kInOlﬁle] #4. Octane gas (Cngg) gas is burned steadily with 30% excess air at 25 °C and 60% relative humidity.
Assuming combustion is complete and the products leave the combustion chamber at 600 K, determine the heat transfer for this process per unit mass of octane. #5. Propane (C3Hg) gas is burned adiabatically with 20% excess air, both reactants initially at 298 K. a) Find the maximum combustion temperature for the steady ﬂow process
b) Evaluate the entropy generation for the reaction in kK/kmol-K if the fuel and oxidizer are initially separate and both at 1 atm. ...
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