short note on reheating
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The Reheat Cycle
In basic rankine cycle, after the isentropic development in turbine, steam is specifically fed into condenser for condensation process. There are two turbines in the reheat system which is utilized for enhancing effectiveness. Steam, after extension from high pressure turbine, is sent again to boiler and heated till it comes to superheated condition. It is then left to extend in low pressure turbine to accomplish condenser pressure.
Draw the schematic diagram of reheat rankine cycle as in figure (1).
Draw the enthalpy-entropy diagram for reheat rankine cycle as in figure (2).
The processes of reheat rankine cycle are explained below using the enthalpy-entropy diagram.
Process 1-2
This process is known as high pressure turbine.
Obtain the work-done by turbine using enthalpies of inlet and exit.
Where, h1 is the enthalpy for inlet state 1 and h2 is the enthalpy for outlet state 2.
To find the values of h1 and h2, use the given values of pressure and temperature at point 1 to calculate first entropy at state 1(S1) and enthalpy (h1) from the superheated steam table.
Next to find the variable is dryness fraction to calculate the value of entropy at exit state 2 (S2) with the given formula.
Write the formula for enthalpy at exit state 2.
In basic rankine cycle, after the isentropic development in turbine, steam is specifically fed into condenser for condensation process. There are two turbines in the reheat system which is utilized for enhancing effectiveness. Steam, after extension from high pressure turbine, is sent again to boiler and heated till it comes to superheated condition. It is then left to extend in low pressure turbine to accomplish condenser pressure.
Draw the schematic diagram of reheat rankine cycle as in figure (1).
Draw the enthalpy-entropy diagram for reheat rankine cycle as in figure (2).
The processes of reheat rankine cycle are explained below using the enthalpy-entropy diagram.
Process 1-2
This process is known as high pressure turbine.
Obtain the work-done by turbine using enthalpies of inlet and exit.
Where, h1 is the enthalpy for inlet state 1 and h2 is the enthalpy for outlet state 2.
To find the values of h1 and h2, use the given values of pressure and temperature at point 1 to calculate first entropy at state 1(S1) and enthalpy (h1) from the superheated steam table.
Next to find the variable is dryness fraction to calculate the value of entropy at exit state 2 (S2) with the given formula.
Write the formula for enthalpy at exit state 2.
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