Question

Fuel: 0.84C12H26+0.11C7H8+0.05C2H5OH
Pressure ratio: rp = 16.7
Equivalence ratio: φ = 0.38
The fuel is a three-fuel blend of:

Name          Chemical Formula       h¯◦f
n-dodecane C12H26.           −352,100 kJ/kmol
toluene        C7H8         12,178 kJ/kmol
ethanol        C2H5OH   −277,507 kJ/kmol

For the inlet air conditions, use a temperature of 280 K and a pressure of 100 kPa.

a) 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.

b) 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).

c) 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 ac-
counting for the addition of fuel mass.

• Assume that the compression and expansion are isentropic. Complete the calculations accounting for the variation in specific heats with temper-
ature. Assume that the combustion takes place adiabatically and at constant pressure.

I can perform the adiabatic flame portion of this problem, and I also established the four states. If this seems like a lot of work, please just summarize the following: how I would calculate the flow rate of fuel, calculate the power, and calculate the LHV. If you summarize please make very clear equations with desecption.

Answer 1

hof Name chemical mula 352, co K/kole 2,148 Kkmole C118 elhoral 33 -0.05 3242 1.88 20 8.G

ㄒ fh maini) Stoic 16.46 16-46 xo.uo ķ.5 (aa/afhahe: 50 Ma C01.8) は,8)': : 68.38%| and we have toner Healaddion

HIA 4688 155. 826 kI/kmole (81)