I want to know how this four pressures and enthalpies are selcected 8.6. A steam power plant employs two adiabatic turbines in series. Steam enters the firstturbine at 650°C and 7000 kPa and discharges from the second turbine at 20 kPa. Thesystem is designed for equal power outputs from the two turbines, based on a turbineefficiency of 78% for each turbine. Determine the temperature and pressure of thesteam in its intermediate state between the two turbines. What is the overall efficiencyof the two turbines together with respect to isentropic expansion of the steam from theinitial to the final state?A steam power plant employs two adiabatic turbines in series. Steam enters the first turbine at 650and 7,000 kPa and discharges from the second turbine at 20 kPa. The system is designed for equalpower outputs from the two turbines, based on a turbine efficiency of 78% for each turbine.Given the initial temperature and pressure to be T₁ = 923.15K, P₁ = 7000kPaH₁ = 3766.38kJ/kgHence from steam tables,S₁ = 7.22kJ/kgKAt 20 kPa, the values for saturated liquid and vapour are as follows:Hlig = 251.45kJ/kg, Hvap = 2609.9kJ/kgSliq=0.832kJ/kgK, Svap = 7.909kJ/kgKThe four values of pressure and the corresponding enthalpies are as follows:725750775800P₂kPa, H₂3023.93032.53040.93049.0Actual work is given by n(h₂' -h₁)H₂act=The actual enthalpy and entropy are hence-579.15 +3766.4-572.442 +3766.4-556.89 +3766.4559 579 3766 4.0.78(3023.93766.4)0.78(3032.5 3766.4)0.78 (3040.93766.4)0.78(30493766.4)3187.33194.03200.53206 8.why this 4 Pressuresare selected?kJ/kg=-579.15-572.442-565.89-559.512

Since in solution we have given Four pressure values: and

Answered: I want to know how this four pressures…

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Mechanical Engineering

I want to know how this four pressures and enthalpies are selcected

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

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Concept explainers

Work and Heat Transfer

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Question

I want to know how this four pressures and enthalpies are selcected

8.6. A steam power plant employs two adiabatic turbines in series. Steam enters the first
turbine at 650°C and 7000 kPa and discharges from the second turbine at 20 kPa. The
system is designed for equal power outputs from the two turbines, based on a turbine
efficiency of 78% for each turbine. Determine the temperature and pressure of the
steam in its intermediate state between the two turbines. What is the overall efficiency
of the two turbines together with respect to isentropic expansion of the steam from the
initial to the final state?
A steam power plant employs two adiabatic turbines in series. Steam enters the first turbine at 650
and 7,000 kPa and discharges from the second turbine at 20 kPa. The system is designed for equal
power outputs from the two turbines, based on a turbine efficiency of 78% for each turbine.
Given the initial temperature and pressure to be T₁ = 923.15K, P₁ = 7000kPa
H₁ = 3766.38kJ/kg
Hence from steam tables,
S₁ = 7.22kJ/kgK
At 20 kPa, the values for saturated liquid and vapour are as follows:
Hlig = 251.45kJ/kg, Hvap = 2609.9kJ/kg
Sliq=0.832kJ/kgK, Svap = 7.909kJ/kgK
The four values of pressure and the corresponding enthalpies are as follows:
725
750
775
800
P₂
kPa, H₂
3023.9
3032.5
3040.9
3049.0
Actual work is given by n(h₂' -h₁)
H₂act
=
The actual enthalpy and entropy are hence
-579.15 +3766.4
-572.442 +3766.4
-556.89 +3766.4
559 579 3766 4.
0.78(3023.93766.4)
0.78(3032.5 3766.4)
0.78 (3040.93766.4)
0.78(30493766.4)
3187.3
3194.0
3200.5
3206 8.
why this 4 Pressures
are selected?
kJ/kg
=
-579.15
-572.442
-565.89
-559.512

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