(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Adiabatic Steam turbine produces 4000 kW

Steam is fed at 21 bar/475 deg C

Exhaust is saturated steam (P=0.1bar)

Exhaust is fed into condenser where it is cooled to 30 deg C

Problem asks for flow rate of cooling water supplied to condensener if water enters at 15 deg C and is heated to 25 deg C

2. Relevant equations

Turbine:

Assume Q = 0

H2 - H1 = -W

m dot steam * (H2 - H1) = - Power (or W dot)

Condenser:

Power (in) = Power(out)

m dot steam in (H steam in) + m dot water in (H water in) = m dot steam out (H steam out) + m dot water out (H water out)

m2U2 - m1U1 - H'(m2 - m1) = 0

3. The attempt at a solution

i fond the mass flow rate of steam going into turbine using m dot * delta H = -Power

- 4000 kW (1 kJ/s / 1 kW) = m dot steam (2584.8 kj/kg - 3411.3 kJ/kg)

mass flow of steam = 4.84 kg/s

then when i try to use the last equation in the above section I get stuck because I can't

figure out U2 or the outlet states. H' = 2779.7 kj/kg, U1 = 2438.0 kJ/kg, m1 = 25000 kg, m2 =?

please help!

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# Homework Help: Mass flow rate of cooling water in condenser needed

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