9.10 A reheat-regenerative engine receives steam at 207 bar and 593°C, expanding it to 38.6 bar, 343°C. At this point, the steam passes through a reheater and reenters the turbine at 34.5 bar, 593°C, whence it expands to 9 bar, 427°C, at which point steam is bled for feedwater heating. Exhaust
Problems
occurs at 0.7 bar. Beginning at the throttle (point 1), these enthalpies are known (kJ/kg):
$h_1 = 3511.3$
$h_2 = 3010.0$
$h_2 = 3082.1$
$h_3 = 3662.5$
$h_4 = 3205.4$
$h_4' = 3222.9$
$h_5 = 2308.1$
$h_6 = 162.2$
$h_7 = 742.1$
$h_7' = 724.2$
For the ideal engine, sketch the events on the Ts plane, and for 1 kg throttle steam, find (a) the mass of bled steam, (b) the work, (c) efficiency, and (d) the steam rate. In the actual case, water enters the boiler at 171°C and the brake engine efficiency is 75%, (e) Determine the brake work and the brake thermal efficiency. (f) Let the pump efficiency = 65%, and estimate the enthalpy of the exhaust steam.