Air at 400 kPa and 600 K enters a Turbine operating at a steady state and exits at 100 kPa and 300 K. Heat transfer from the turbine to the surroundings occurs at a rate of 30 kJ/kg. Kinetic and potential energy effects are negligible. Air is an ideal gas where c(p)=1.1 kJ/kg*K.
1) determine h1, h2, h3, and h4.
2) find rate of power production in kJ/kg of flowing air.
Ok so I\'ve been working this problem for almost 2 hours now, and feel like i\'m getting nowhere with it. What I know so far is:
p1=400 kPa (4 bar)
t1=600 K
p(2 or 3? i\'m not sure)=100 kPa (1 bar)
t(2 or 3)=300 K
c(p) (of air)=1.1 kJ/kg*K
Q(dot)/m=-30 kJ/kg (negative due to heat transfer FROM turbine)
W(dot)cv/m=?
h1, h2, h3, h4=?
the turbine pictured has an arrow going in from the top left corner, and an arrow going out (bottom right corner). I know that the top left corner is my p1/t1, but I have no clue if the bottom right would be p3/t3 assuming you\'d work from left to right. Would really appreciate the help though, because this is driving me crazy.
Solution
Enthalpy values at each point is C p T.So in order to find the enthalpy values find temperature. To get the work done Take the difference of enthalpy values at entry and exit of the turbine,substract heatloss from this value you will get work done.
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Air at 400 kPa and 600 K enters a Turbine operating at a steady state.docx
1. Air at 400 kPa and 600 K enters a Turbine operating at a steady state and exits at 100 kPa and
300 K. Heat transfer from the turbine to the surroundings occurs at a rate of 30 kJ/kg. Kinetic
and potential energy effects are negligible. Air is an ideal gas where c(p)=1.1 kJ/kg*K.
1) determine h1, h2, h3, and h4.
2) find rate of power production in kJ/kg of flowing air.
Ok so I've been working this problem for almost 2 hours now, and feel like i'm getting nowhere
with it. What I know so far is:
p1=400 kPa (4 bar)
t1=600 K
p(2 or 3? i'm not sure)=100 kPa (1 bar)
t(2 or 3)=300 K
c(p) (of air)=1.1 kJ/kg*K
Q(dot)/m=-30 kJ/kg (negative due to heat transfer FROM turbine)
W(dot)cv/m=?
h1, h2, h3, h4=?
the turbine pictured has an arrow going in from the top left corner, and an arrow going out
(bottom right corner). I know that the top left corner is my p1/t1, but I have no clue if the bottom
right would be p3/t3 assuming you'd work from left to right. Would really appreciate the help
though, because this is driving me crazy.
Solution
2. Enthalpy values at each point is C p T.So in order to find the enthalpy values find temperature.
To get the work done Take the difference of enthalpy values at entry and exit of the
turbine,substract heatloss from this value you will get work done.
