Question

Steam enters a turbine at 8000 kPa, 440oC. At the exit, the pressure and quality are 150 kPa and 0.19, respectively.

Determine the power produced (kW) by the turbine if the mass flow rate is 1.57 kg/s and the heat transfer from the turbine to the surroundings is 2.93 kW.

Answer 1

`\dot W_(out) = 3863.98\,kW`

Step-by-step explanation:

The turbine at steady-state is modelled after the First Law of Thermodynamics:

`-\dot Q_(out) -\dot W_(out) + \dot m \cdot (h_(in)-h_(out)) = 0`

The specific enthalpies at inlet and outlet are, respectively:

Inlet (Superheated Steam)

`h_(in) = 3353.1\,(kJ)/(kg)`

Outlet (Liquid-Vapor Mixture)

`h_(out) = 890.1\,(kJ)/(kg)`

The power produced by the turbine is:

`\dot W_(out)=-\dot Q_(out) + \dot m \cdot (h_(in)-h_(out))`

`\dot W_(out) = -2.93\,kW + (1.57\,(kg)/(s) )\cdot (3353.1\,(kJ)/(kg) - 890.1\,(kJ)/(kg) )`

`\dot W_(out) = 3863.98\,kW`