Question

Water (10 kg/s) at 1 bar pressure and 50 C is pumped isothermally to 10 bar. What is the pump work? (Use the steam tables.) -7.3 kJ/s O 7.3 kJ/s -210 kJ/s e345 kJ/s 3451 kJ/s

Answer 1

Answer:

The pump work is 3451 kJ/s

Explanation:

Pump work (W) is calculated as

$W = (h_f - h_i) \times \dot{m}$

where

$h_f$ is the enthalpy of water at its final state

$h_i$ is the enthalpy of water at its initial state

$\dot{m} = 10 kg/s$ is water mass flow

For liquids, properties are evaluated as saturated liquid. From the figure attached, it can be seen that

$h_f = 762.81 kJ/kg$

$h_i = 417.46 kJ/kg$

Replacing

$W = (762.81 kJ/kg - 417.46 kJ/kg) \times 10 kg/s$

$W = 3451 kJ/s$