Superheated steam enters a nozzle that has an inlet diameter that measures 2.5 cm and an outlet diameter that measures 1 cm. Its outlet velocity has been measured at 30 m/s. The steam that enters the nozzle is at 650°C and 1350 kPa and the steam that exits the nozzle is at 400°C and 100 kPa.

A. Determine the velocity of the steam upon entering the nozzle.

B. Determine the rate at which this process gains or loses heat.

C. Example 3-4 and Section 3.6.2 indicate that in modeling a nozzle, it is common to assume the nozzle is adiabatic and that the velocity entering the nozzle is negligible. Do your answers in this case seem consistent or inconsistent with those common assumptions?

Example 3.4

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A gas at T = 450C and P = 5 bar flows at steady state through an adiabatic and revers- ible nozzle. The exiting pressure is 1 bar. Find the velocity and temperature of the exiting stream if A. The gas is steam. B. The gas is an ideal gas with C+= 3R and molecular weight = 75 g/mol. Tin = 450C Pin = 5 bar Tout ? P = 1 bar out V = ?