Air is expanded in a nozzle from a stagnation state of 2 MPa, 600 K, to a static pressure of 200 kPa. The mass flow rate through the nozzle is 5 kg/s. Assume the flow is reversible and adiabatic and determine the throat and exit areas for the nozzle.
\begin{aligned}P ^* & = P _{ o }\left\lgroup \frac{2}{ k +1} \right\rgroup^{ \frac{ k }{ k -1} }\\& =2 \times 0.5283=1.056 \,MPa \\T ^* & = T _{ o } \times \frac{2}{ k +1}=600 \times 0.8333=500 \,K \\v ^* & = RT ^* / P ^*=0.287 \times 500 / 1056 \\& =0.1359 \,m ^3 / kg\end{aligned}
P _2 / P _{ o }=200 / 2000=0.1 \quad \Rightarrow \quad M _2^*=1.701= \mathbf{V} _2 / c ^*
Column with mach no. based on throat speed of sound.