Question

The measured engine fuel flow rate is 0.4g/s, airflow rate is 5.6 g/s and exhaust gas composition (measured dry) is CO2 =13.0% , CO = 2.8% with O2 essentially zero.Unburned hydrocarbon emissions can be neglected. Compare the equivalence ratio calculated from the fuel and airflow with the equivalence ratio calculated from the exhaust gas composition. The fuel is Gasoline with an H/C ratio of 1.87. Assume an H2 concentration equal to one third the CO concentration.

Answer 1

Answer:

b1 = 0.8228, b2 = 1.078, b3 = 0.1772, b5 = 5.472, Φ2 = 1.012 rad, Φ1 = 1.043 rad,

EF= 14 KJ, EFs = 14.6 K,

Explanation:

We are given that the measured engine fuel flow rate is 0.4g/s = 0.004 kh, airflow rate is 5.6 g/s = 0.0056 kg . Therefore the ratio of airflow rate to the engine fuel flow rate = EF = 5.6/0.4 = 14.

We also know that the "fuel is Gasoline with an H/C ratio of 1.87" that is x = 1.87.

The equation for the reaction is given below;

CHx + 1/Φ × (1 + x/ 4) (O2 + 3. 773 N2) ----------------> b1 CO2 + b2 H2O + b3 CO + b4 H2 + b5 N2.

So, if n1 + n2 = 1 ; x = 2 × b2 + 2 × b4.

Note that our EFs = 34.56 [ 4 + x / 12.01 + 1.08 + x ].

Note that Φ1 = EFs/EF = 1.043 radian.

(Where EFs= 14.6).

Then, 1/ Φ2 × [ 1 + x/4 ] = 2 × b1 + b2 + b3. -------------------------------(1).

1/ Φ2 × [1 + x/4] ×2 × 3.773 = 2 × b5. ----------------------(1).

If we solve the above equations we will have b1 = 0.8228, b2 = 1.078, b3 = 0.1772, b5 = 5.472, Φ2 = 1.012 radian.

Pressure of the dry composition = b1 + b3 + b4+ b5 = 6.329 kPa.