- #1

VooDoo

- 59

- 0

Hey guys,

I have been given that the isentropic efficiency of a nozzle = 90%. Inlet condictions are: 5MPa and 550°C and exit: 100kPa.

Now [tex]\eta_{n}(h_{i}[/tex] - [tex]h_{0}[/tex]) = [tex]V^{2}_{i}[/tex]/2

h(o) - h(i) is the enthalpy drop across the turbine.

Now next they say that s(o) = s(i). Now how can the entropy at the entrance of the nozzle be equal to the entropy at the exit if the isentropic efficiency of the nozzle is not equal to one!

Here is a picture of my notes:

http://img259.imageshack.us/img259/6140/111nm6.jpg [Broken]

I have been given that the isentropic efficiency of a nozzle = 90%. Inlet condictions are: 5MPa and 550°C and exit: 100kPa.

Now [tex]\eta_{n}(h_{i}[/tex] - [tex]h_{0}[/tex]) = [tex]V^{2}_{i}[/tex]/2

h(o) - h(i) is the enthalpy drop across the turbine.

Now next they say that s(o) = s(i). Now how can the entropy at the entrance of the nozzle be equal to the entropy at the exit if the isentropic efficiency of the nozzle is not equal to one!

Here is a picture of my notes:

http://img259.imageshack.us/img259/6140/111nm6.jpg [Broken]

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