Handbook of Turbomachinery Second Edition Revised - Ventech!

calculate the relevant thermodynamic losses and to predict the likely
magnitude of the changes in those losses will be central to such an economic
analysis and will help determine which options are viable.
As befits the central importance of thermodynamic losses in turbine
design, maintenance, and operation, numerous references describe these
contributions in great detail [11, 12].
Three groups of losses can be considered: pressure drops that occur
with the passage of steam through valves, piping, and exhaust between
sections; turbine section losses; and individual turbine stage losses. Figure 12
shows that the relative mix and magnitude of efficiency losses varies by type
of stage. The figure shows the major losses for a typical 700 MW single
reheat turbine.
Pressure Drop Losses
A rule of thumb is that every 1% pressure reduction results in a reduced heat
rate of about 0.1% in a fossil unit and 0.15% in a nuclear unit [9].
Figure 12 Stage and section efficiency losses for a 700-Mw single reheat turbine.
Copyright © 2003 Marcel Dekker, Inc.