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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 (H

_{out}-H

_{in})

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

Best regards,

D