Refrigerant 134a enters an insulated diffuser as a saturated vapor at 80°f with a velocity of 1453.4 ft/s. at the exit, the temperature is 280°f and the velocity is negligible. the diffuser operates at steady state and potential energy effects can be neglected. determine the exit pressure in lbf/in2.

Refer to the diagram shown below.

State 1: The inlet

T₁ = 80°F, the inlet temperature

v₁ = 1453 ft/s, the inlet velocity

Saturated vapor

From thermodynamic tables, obtain

h₁ = 113.94 Btu/lbm, the enthalpy

p₁ = 101.45 psia, the inlet pressure

State 2: The outlet

T₂ = 280 F, the outlet temperature

v₂ = 0, the outlet velocity

From thermodynamic tables, obtain

h₂ = 163.76 Btu / (lbm-R)

p₂ = 40 psia, the exit pressure

Answer: 40 psia