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HethensEnd25
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Homework Statement
A pump with inlet of saturated liquid at 600kPa has an exit stream of 10MPa calculate work
Homework Equations
Energy balance equation
Entropy balance equation
Linear interpolation
Steam table
The Attempt at a Solution
My attempt at the solution was to calculate the entropy of the fluid at the inlet. I know since a pump is isentropic
ΔS=0
And that through an energy balance for a pump
Wp=m (Hout-Hin)
Where the work i know has to be positive.
I interpolated from the data a value for my entropy (1.93) and since I know it to be isentropic I used that point to find a value for enthalpy. My problem is doing that route I get a smaller value of enthalpy going out because the entropy data points for my interpolation are larger than my calculated value. This result leaves me with a negative value for work which I know to be wrong.I did however attempt it another way with the approach of knowing it to be a saturated liquid at the outlet @10MPa which gave me a different value of enthalpy leaving me with a positive value for work.
Do I just use that value or do I need to interpolate other data points to get a value for entropy ie; using temperature Any and all help is appreciated
D