Question

Air with a stagnation temperature of 430o C and a stagnation pressure of 1.6 MPa enters a constant-area duct in which heat is transferred to the air. The Mach number at the inlet to the duct is 3 and the Mach number at the exit to the duct is 1. Determine the stagnation temperature and the stagnation pressure. Ignore the effects of friction.

Answer 1

To* = 1074.9k ( stagnation temperature )

Po* = 0.467 MPa ( stagnation pressure )

Step-by-step explanation:

Given data:

Po1 = 1.6 MPa

To = 430°c + 273 = 703 k

Mach number at inlet ( M1 )= 3

Mach number at exit ( M2 ) = 1

at M1 = 3

To1 / To* = 0.65398 ( value gotten from Rayleigh's flow gas tables )

therefore To* = 1074.9k

also

Po1 / Po* = 3.42445 ( value gotten from Rayleigh's flow gas tables )

therefore Po* = 0.467 MPa

at M2 = 1

To2 = To* = 1074.9k

Po2 = Po* = 0.467 MPa

using both Rayleigh's flow table and Isentropic Tables the values of stagnation temperature and stagnation pressure are the same at the exit