Determine the size of fuel orifice to give A:F=12:1. The diameter of venture throat is 3.5 cm and the vacuum at the venture is 6.9 of Hg. The pressure and temperature of atmospheric air are 1.013 bar and 25°C. The nozzle lip=5 mm. Take C$d_{s}$ =0.9, C$d_{f}$ =0.7, density of fuel 760Kg/$m^{3}$ .Consider the compressibility of air.

h = 5 mm

$p_{1}$ = 1.013 bar

$T_{1}$ = 25 ° C = 25+273 = 298 K

$C_{ds}$ = 0.9

$C_{f}$ = 0.7

$\rho_{f}$ = $760 Kg/m^{3}$

Vacuum at the venture is

Pressure after venture,

$_{a}$ = mass flow rate of air

$_{f}$ = mass flow rate of fuel

Considering Compressibility of air,

(a) Mass Flow Rate of Air,

For air, $C_{p}$ = 1005 J/kg K , R = 287 N m/kg K and $\gamma$ = 1.4 On substituting these values,

(b) Mass Flow Rate of Fuel,

(c) Air-Fuel Ratio,

Air-Fuel Ratio

The size of fuel orifice,