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This is the science page, where you can find some scientific panza's programs.




A simple simulation:

repeated heating gas turbine

(closed joule cycle)

 

 

During our studies of Energetics, a couple of colleagues and I developed a simulation of a Gas Turbine with repeated heating plant. We used the following variable:

 

INPUT

OUTPUT

T1; Tamb = TL

- Energetic balances

p1; pamb

- Entropic balances

his,C

  • Exergetic balances

For the parts and for the entire plant

his,Thp, his,Tlp

 

b = p1/p2

- h (termodynamic efficiency)

Lutil

- y (exergetic efficiency)

TH

  • dC, dSC1, dSC2, dT1, dT2, dSC3

(efficiency defeats)

T3 = T5

ì We also calculated the p4 that

p4

Maximize the termodynamic efficiency

 

HYPOTHESIS: Air with cp and cv = ƒ(T); ideal gas

p2 = p3; p4 = p5; p6 = p1

 

REFERRING VALUES: 1200 £ TH £ 1400 °C 0 £ Tamb £ 20 °C

pamb = 1,01 bar 6 £ b £ 12

85 £ his,C £ 90 85 £ his,T £ 90

800 £ Tmax £ 1100 °C

To calculate the optimal intermediate pressure (pint), we used a subroutine that, giving to pint the maximum pressure (pmax) value and decreasing by 0,1 bar steps (enough to appreciate variations on plant properties), compares the value of each cycle with the previous and it stops when the current value in lower than the previous. This is based on the hypothesis, by us followed, that the function between the thermodynamic efficiency and the intermediate pressure should be a concave function.

We checked this hypothesis modifying the routine: instead of verifying the above cited condition, the routine stores in a file 50 values of pint with the related values of thermodynamic plant efficiency and work. It's possible to use these values to plot a graphic that shows the real function. You can see that this function matches the hypothesis.

 If you want you can download the source code in Qbasic here (sorry, it is in Italian, but in respect of my colleagues' work I didn't translate it): joule.zip

 


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