A simplified schematic drawing of the carburetor of a gasoline

(S = 0.75) engine is shown in Fig. P5.96. The throat area is 0.5 in.2

.

The running engine draws air downward through the carburetor Venturi

and maintains a throat pressure of 14.3 psia. The low throat pressure

draws fuel from the float chamber and into the airstream. The energy

losses in the 0.07-in.-diameter fuel metering line and valve are given by

where K = 6.0 and V is the fuel velocity in the metering line.

Assume that the air is an ideal fluid having a constant density ρA

= 0.075 lbm/ft3

. The atmospheric pressure is 14.7 psia. Calculate

the air-to-fuel ratio (m˙ a/m˙f).