Name:

Problem 4: [30%]

percent excess air that also enters at 25°C. The products leave the combustion chamber at 1200

A special n-Dodecane fuel (C12H26) at 25°C is burned in a steady-flow combustion chamber with

Assuming combustion is complete, write the balanced equation [5%] and determine the following:

C12H26+.

a) 5%] Fill in the following table:

Substance

hº,

kJ/kmol

C12H26

0₂

N₂

H₂O (g)

CO₂

_H₂0+0₂ +_______N₂

(0₂ +3.76N₂)→CO₂+H₂0+.

C12H26

25°C

Air

80% excess air

25°C

h298K

kJ/kmol

3500 kJ/s

Combustion

chamber

P= 1 atm

KTE

ZON

h1200K

kJ/kmol

Products

1200K

Nas/nName:

2

b) [10% ] Calculate the heat transfer per kmol of the fuel

c) 5% determine the required mass flow rate of the fuel to supply heat at a rate of 3500 kJ/s.

d) [5%] determine the required mass flow rate of air in “kg/s”.