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The entropy of steam increases in actual steam turbines as a result of irreversibilities. In an effort to control entropy increase, it is proposed to cool the steam in the turbine by running cooling water around the turbine casing. It is argued that this will reduce the entropy and the enthalpy of the steam at the turbine exit and thus increase the work output.

How would you evaluate this proposal?

Respuesta :

shallomisaiah19

Answer:

The proposal is not accepted because of greater reduction in work output and efficiency

Explanation:

The following factors influence the turbine output with the suggestion below

1 - Enthalpy at the turbine exit

2 - Heat losses in the turbine

The work output of the steam turbine is

[tex]W=m(h_1-h_2)-Q_{loss}[/tex]

Where,

m is the mass of thee steam flowing through the turbine,

h₁ is the specific enthalpy of the steam leaving the turbine, and

[tex]Q_{loss}[/tex] is the heat loss from the turbinee due to the cooking water.

Enthalpy at the turbine exit; on cooling the turbine with the cooling water, the beck pressure of the turbine is decrease.

this further decrease the specific enthalpy at the turbine exit.

the result is greater reduction in the work output and efficiency,

Heat losses in water in the turbine;

On passing the cooking water around the turbine mst of the heat is carried away by this cooliing water. As the heat losses increases in the turbine, there is a greater reduction in the work output and efficiency.

Therefore, The proposal is not accepted because of greater reduction in work output and efficiency

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