2.33 m3/s of air at 0.276 MPa, 43°C which is heated at this pressure to 430°C and finally expanded in a turbine which delivers 860 kW.During expansion there is a heat transfer of 0.09 MJ/s to the surroundings. Calculate the turbine exhaust temperature if changes in kinetic and potential energy are negligible. - Mumbai university > MECH > SEM 3 > THERMO

Marks: 10M

Year: May 2014

Given:

v = 2.33 m3/s; P1 = 0.276 MPa; $T_1 = 43^oC$; $T_2 = 430^oC$; W = 860 kW; Q = 0.09 MJ/s

Solution:

Applying Ideal Gas equation at 2,

$P_2 = ρRT_2$

$0.276 × 10^6 = ρ × 287 × 703 $

$ρ = 1.3679kg/m^3$

The Steady Flow Energy Equation is given as:

Q - W = ΔKE + ΔPE + Δh

$(-90-860) = 0+0+(2.33 × 1.3679 × 1.005 * (T_2 - T_3)$

$\frac{-950 × 10^3}{1.005 × 2.33 × 1.3679} = 703 - T_3$

$T_3 = 406.428K = 133.428^o c$