Rankine Cycle question?
Question by tru5t_c0: Rankine Cycle question?
Consider a simple ideal Rankine cycle. If the condenser pressure is raised while keeping turbine inlet state the same, (select the correct statement)
a. the pump work input will increase.
b. the amount of heat rejected will decrease.
c. the turbine work output will increase.
d. the cycle efficiency will decrease.
e. the moisture content at turbine exit will increase.
This is for test reviews im trying to gain more of an understanding of the rankine cycle i appreciate teh help
Best answer:
Answer by Ivan A
a. the pump work input will increase.=> Nope, the pump work will decrease as the pressure difference low-high has been decreased.
b. the amount of heat rejected will decrease.=> Yes, there is less heat removal required to bring the water to a saturated liquid state (quality factor = 0 ).
c. the turbine work output will increase.=> Nope, the steam was let to expand less so the output work will decrease.
d. the cycle efficiency will decrease.=> Nope, because even though the work output has been decreased, the work needed at the pump has also been decreased. These two offset out, efficiency remains the same.
e. the moisture content at turbine exit will increase.=> Nope, the quality factor is larger if you increase the pressure at the condenser (assuming that the turbine is an isentropic expansion).
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