Energy Conversion Project -- 4
Budget: $10 – $45 USD
4th December:
Fuel: 0.82 C12H26 + 0.11 C8H10 + 0.07 C2H5OH
Pressure ratio: rp = 20.1 Equivalence ratio: φ = 0.45
Calculate the thermal efficiency of a gas turbine engine burning real fuel. The fuel is a three-fuel blend of
Name Chemical Formula h¯◦ f
n-dodecane C12H26 −352 100 kJ/kmol
xylene C8H10 −24 400 kJ/kmol
Ethanol C2H5OH −277 507 kJ/kmol
The numbers in your fuel specification above are mole fractions.
• For the inlet air conditions, use a temperature of 280 K and a pressure of 100 kPa.
• Calculate the net engine power for an air mass flow rate of 50 kg/s.
• Except during combustion, assume that the working fluid is air, but account for the added fuel mass after the combustor.
• Calculate the thermal efficiency based on the calculated work, the fuel to air ratio, and the lower heating value of your fuel (which you must also calculate).
• In connection with the previous item, compare the heat input per unit mass (qin) based on the lower heating value with the one based on the air enthalpy but accounting for the addition of fuel mass.
• Assume that the compression and expansion are isentropic.
• Complete all calculations accounting for the variation in specific heats with temperature.
• Assume that the combustion takes place adiabatically and at constant pressure.
It should consist of
• Title page
• Executive Summary (1 page)
• Introduction – Statement of the problem
• Thermodynamic analysis – Written description of the calculations. – A quantitative T-s diagram for the cycle. – Present each state temperature (1–4), each state pressure, each state enthalpy (for air), each state s ◦ , the balanced combustion reaction, the power output, and the thermal efficiency in tabular form
conclusion
Fuel: 0.82 C12H26 + 0.11 C8H10 + 0.07 C2H5OH
Pressure ratio: rp = 20.1 Equivalence ratio: φ = 0.45
Calculate the thermal efficiency of a gas turbine engine burning real fuel. The fuel is a three-fuel blend of
Name Chemical Formula h¯◦ f
n-dodecane C12H26 −352 100 kJ/kmol
xylene C8H10 −24 400 kJ/kmol
Ethanol C2H5OH −277 507 kJ/kmol
The numbers in your fuel specification above are mole fractions.
• For the inlet air conditions, use a temperature of 280 K and a pressure of 100 kPa.
• Calculate the net engine power for an air mass flow rate of 50 kg/s.
• Except during combustion, assume that the working fluid is air, but account for the added fuel mass after the combustor.
• Calculate the thermal efficiency based on the calculated work, the fuel to air ratio, and the lower heating value of your fuel (which you must also calculate).
• In connection with the previous item, compare the heat input per unit mass (qin) based on the lower heating value with the one based on the air enthalpy but accounting for the addition of fuel mass.
• Assume that the compression and expansion are isentropic.
• Complete all calculations accounting for the variation in specific heats with temperature.
• Assume that the combustion takes place adiabatically and at constant pressure.
It should consist of
• Title page
• Executive Summary (1 page)
• Introduction – Statement of the problem
• Thermodynamic analysis – Written description of the calculations. – A quantitative T-s diagram for the cycle. – Present each state temperature (1–4), each state pressure, each state enthalpy (for air), each state s ◦ , the balanced combustion reaction, the power output, and the thermal efficiency in tabular form
conclusion