Steam enters a turbine with a velocity of 20 ms-1, a pressure of 3 bar,
internal energy of 3500 kJ kg-1 and density of 1.7 kg ms-3. The steam
leaves the turbine with a velocity of 30 m s-1, an internal energy of
2900 kJ kg-1, density of 0.7 kg m-3 and at a pressure of 1.2 bar. If heat is
lost to the surroundings at the rate of 30 kW and the output power of the
turbine is 5 MW, calculate :
(a) the enthalpy of the steam at entry and exit from the turbine
(b) the entry and exit areas of the turbine.© BrainMass Inc. brainmass.com June 4, 2020, 1:39 am ad1c9bdddf
(a) The equation which relates the (specific) enthalpy to the (specific) internal energy is
where h = specific enthalpy [J/kg], 1kJ/kg = 103 J/kg
u = specific internal energy [J/kg]
p = pressure [Pa], 1 bar = 105 Pa
= density [kg/m3]
We will denote [ ]1 the inlet parameters and [ ]2 the exit parameters.
Replacing with given numerical values, we will get:
The expert examines a turbine thermo steam velocity.