Question

A First Stage in a turbine receives steam at 10 MPa, 800 C with an exit pressure of 800 KPa. Assume the stage is adiabatic and reversible. Find the exit temperature and the specific work.

Answer 1

given,

P₁ = 10 MPa T₁ = 800

P₂ = 800 KPa T₂ = ?

Using formula

`(T_2)/(T_1) = ((P_2)/(P_1))^{(n-1)/(n)}`

For steam n = 1.33

`(T_2)/(800+273) = ((800* 10^(3))/(10* 10^(6)))^{(1.33-1)/(1.33)}`

T₂ = 573.368 K

T₂ = 573.368 - 273 = 300.368 °C

`W = (P_1V_1-P_2V_2)/(n-1)`

=
`(mR(T_1-T_2))/(n-1)`

=
`(1* 0.287* (800 - 300.368))/(1.33-1)`

W = 434.53 kJ/kg