Question

Sonic flow exists at the throat of an equilibrium chemically reacting nozzle flow?

(a) True

(b) False

The question was asked in a national level competition.

My question comes from Area-Velocity Relation in portion Quasi-One-Dimensional Flow of Aerodynamics

Answer 1

Correct option is (a) True

Easy explanation: According to the area-velocity relation for a quasi one-dimensional flow, the relation is given as:

\(\frac {dA}{A}\)=(M^2-1)\(\frac {du}{u}\)

For sonic flow, Mach number = 1. Therefore for M=1 we get \(\frac {dA}{A}\)=0, thus sonic flow does exist for an equilibrium reacting nozzle flow at the throat.