See please the attachRaschjot STU.sm (292 KiB) downloaded 59 time(s).

Hi. I don't understand how you get Q5 = 77.8518 % given that at T5 = 32.88°C and P5 = 5 kPa it must tu be Q5 = 50 %.

This is a more direct way of solving the problem, in the sense that the same results are obtained. A great advantage of using functions of two variables for thermodynamic variables is that now you don't have to look them up in tables, and therefore you no longer need to separate the vapor and liquid parts to find them in tables.

Raschjot STU.sm (574 KiB) downloaded 39 time(s).

Best regards.
Alvaro.

Wrote

Hi. I don't understand how you get Q5 = 77.8518 % given that at T5 = 32.88°C and P5 = 5 kPa it must be Q5 = 50 %.
Raschjot STU.sm (574 KiB) downloaded 39 time(s).

Best regards.
Alvaro.

At T5 = 32.88°C and P5 = 5 kPa it Q5 must be from 0 % to 100%.

If Q5=50% - it is not a steam turbine - it is a 50% steam turbine and a 50% water turbine ;-)
Calculation with WaterSteamPro

Wrote

Wrote

Hi. I don't understand how you get Q5 = 77.8518 % given that at T5 = 32.88°C and P5 = 5 kPa it must be Q5 = 50 %.
Raschjot STU.sm (574 KiB) downloaded 39 time(s).

Best regards.
Alvaro.

At T5 = 32.88°C and P5 = 5 kPa it Q5 must be from 0 % to 100%.

If Q5=50% - it is not a steam turbine - it is a 50% steam turbine and a 50% water turbine ;-) ...

You're right. I put the numbers backwards. The correct question is why do you use Q5 = 50% since the correct value is Q5 = 77.85%?

In the attached file, in addition to showing the most direct way to calculate all the states, the T-s and T-h diagrams are added.

Raschjot STU Ideal.pdf (398 KiB) downloaded 48 time(s).
Raschjot STU Ideal.sm (308 KiB) downloaded 45 time(s).

Best regards.
Alvaro.

Wrote

Wrote

Wrote

Hi. I don't understand how you get Q5 = 77.8518 % given that at T5 = 32.88°C and P5 = 5 kPa it must be Q5 = 50 %.
Raschjot STU.sm (574 KiB) downloaded 39 time(s).

Best regards.
Alvaro.

At T5 = 32.88°C and P5 = 5 kPa it Q5 must be from 0 % to 100%.

If Q5=50% - it is not a steam turbine - it is a 50% steam turbine and a 50% water turbine ;-) ...

You're right. I put the numbers backwards. The correct question is why do you use Q5 = 50% since the correct value is Q5 = 77.85%?

In the attached file, in addition to showing the most direct way to calculate all the states, the T-s and T-h diagrams are added.

Raschjot STU Ideal.pdf (398 KiB) downloaded 48 time(s).
Raschjot STU Ideal.sm (308 KiB) downloaded 45 time(s).

Best regards.
Alvaro.

We can use Q=1, 0, 77.85% etc