Thermodynamics: How to draw the P-V diagram on Excel.?

Question

On the Excel, I want to draw the P-V diagram of Stirling cycle. All my P and V cordinates are know and I have manage to plot this on excel.

However at stage 1-2 and 3-4, the lines are straight and the question is that for this two isthermal processes (at stage 1-2 and 3-4), how can I fit an appropriate curve to each process.

Answer 1

So, you are good to go for steps 2-3 and 4-1, right ?

Steps 1-2 and 3-4 are isothermal so PV=C where C = constant and you KNOW the value of C, right ?

Rearrange this equations to: P = C / V. Use this form of the equation to generate points along the curve for steps 1-2 and 3-4.

In Excel, you have a table of your PV data for your plot. Now instead of just the 4 corners, you now need to include a few extra points for steps 1-2 and 3-4. It is NOT easy to make a table in this program , but I used COMMAS to show the entries in 2 adjacent cells in the same row. So, P values are in column A and V values are in column B. Your new table might look like:



P , V

-----------------------------------------

P1 , V1

P1a=C/V1a , V1a=V1+(V2-V1)/5

P1b=C/V1b , V1b=V1a+(V2-V1)/5

P1c=C/V1c , V1c=V1b+(V2-V1)/5

P1d=C/V1d , V1d=V1c+(V2-V1)/5

P2 , V2

P3 , V3

P3a=C/V1a , V3a=V3+(V4-V3)/5

P3b=C/V1b , V3b=V3a+(V4-V3)/5

P3c=C/V1c , V3c=V3b+(V4-V3)/5

P3d=C/V1d , V3d=V3c+(V4-V3)/5

P4 , V4

P1 , V1



When you make the plot, be sure to tell excel that you want a smooth curve through the points. This will make the paths for steps 1-2 and 3-4 look great.



Visit my Thermo website at LearnThermo.com (the tutorials are under construction, but there are many example problems with solutions. You can also post questions on my blog at LearnThermo.blogspot.com.

Answer 2

T-s Diagram Generator

Answer 3

so how to find the final state, final temperature and final specific volume? i didn't get it.