A simplified schematic diagram of a carburetor of a gasoline engine is shown in Fig. P11.38. The

Question:

A simplified schematic diagram of a carburetor of a gasoline engine is shown in Fig. P11.38. The throat area is \(0.5 \mathrm{in}^{2}\). The engine draws air downward through the carburetor Venturi and maintains a throat pressure of 14.3 psia. This low throat pressure draws fuel from the float chamber and into the air stream. The energy losses in the 0.06-in. I.D. fuel line and valve are given by

\[ h_{L}=\frac{K V^{2}}{2 g} \]

with \(K=6.0\). The fuel specific gravity is 0.75 . Assume an atmospheric pressure of 14.7 psia. Find the air-fuel ratio (that is, the ratio of the air mass flow rate to the fuel mass flow rate) based on an

(a) ideal (constant density and inviscid) air flow

(b) an isentropic air flow.

Figure P11.38