Critical (throat) pressure in a De Laval nozzle: superheated steam 10 bar → 0.1 bar Given: Superheated steam expands from 10 bar to 0.1 bar in a De Laval nozzle. Find: Pressure at the minimum area (throat) at choked condition using the standard critical ratio for superheated steam. Choose the correct option.

GivenUpstream pressure p₁ = 10 bar (superheated)Critical pressure ratio for superheated steam ≈ 0.546

Step-by-stepp_throat = 0.546 × p₁= 0.546 × 10 bar= 5.46 bar

Common pitfallUsing the wet-steam critical ratio (≈ 0.577) would give 5.77 bar, which is not applicable here since the prompt specifies superheated steam.

Final Answer5.46 bar