Last Updated: 5/28/2009
Free Excel/VBA Spreadsheets for Thermodynamics:
Rankine Cycle, Brayton Cycle, Otto and Diesel Cycles
If you click on any of the entries below, that Microsoft Excel workbook will be downloaded to your computer. Each of them involves at least one module written in Visual Basic for Applications (VBA), Excel's macro language. All were written under Windows, but should work under MS Office running on a Macintosh. Earlier versions of MS Office on both platforms may not support all features used in these workbooks.
Disclaimer
No warranties, expressed or
implied, are made that these programs are free from error, or are consistent
with any particular standard of merchantability, or will meet your requirements
for any particular application. These programs should not be relied on for
solving problems whose incorrect solution could result in injury or lost
property. If you use these program in such a manner, it is at own risk. The
author disclaims all liability for direct or consequential damages resulting
from your use of these programs, i.e., SOFTWARE THAT IS FREE HAS NO GUARANTEE!
Each of these Excel workbooks
contains at least one macro written in Visual Basic for Applications (VBA).
When you open one of them in Excel 2003 or earlier, you will probably see a
warning like, "[filename] contains macros. Macros may contain viruses. It
is always safe to disable macros, but if the macros are legitimate, you might
lose some functionality." Then you are given the choices: "Disable
Macros", "Enable Macros" and "More Info". In the case
of these spreadsheets, you must select "Enable Macros" or they will
not work at all! (If you not even offered this choice, then your security is
probably set at "High." You must have your security level in Excel
set at "Medium" first, before you even open the workbook. This allows
you to "choose whether or not to run potentially unsafe macros.") When you open one in Excel 2007, you
will get a warning on the command line and can choose to enable macros
there.
My virus checker is set to update automatically every day (yours should be too!). You should scan these materials (and anything else containing macros you download from the Internet) before opening them, but then you MUST enable macros!
Brayton Cycle (Cold
Air Standard) Template including Regeneration (Updated 5/12/2009)
This spreadsheet
provides a template for analysis of the Brayton Cycle using the Cold Air Standard
(constant specific heats). The user
must fill in the data in the top grid.
From that data, the cells in the second grid are updated, and
Pressure-volume and Temperature-entropy diagrams are generated. Make sure your volume is set up high
when you open it! A second
sheet in the same workbook (not seen below but operating in a similar fashion)
is set up to include Regeneration.
For photos of aircraft powered by the Brayton cycle (Turbofans and
Turboprops) as well as some powered by the Otto cycle, click here.
Rankine Cycle Template (Updated 5/12/2009)
This spreadsheet
provides a template for analysis of the Rankine (Steam) Cycle. The user must fill in the data in the
top grid (from other software or table lookup). From that data, the cells in the second
grid are updated, and Pressure-volume and Temperature-entropy diagrams are
generated. If you use the
thermal properties Excel add-in from Spreadsheetworld.com, then you can have
the whole spreadsheet update whenever any input parameter is changed.
Otto Cycle Template
(Updated 5/12/09)
This spreadsheet
provides a template for analysis of the Otto (spark-ignition, internal combustion)
Cycle. The user must fill in the
data in the top grid (from other software or table lookup). From that data, the cells in the second
grid are updated, and Pressure-volume and Temperature-entropy diagrams are
generated. If you use the
thermal properties Excel add-in from Spreadsheetworld.com, then you can have
the whole spreadsheet update whenever any input parameter is changed. This updated spreadsheet includes the
capability of doing a sensitivity analysis. Turn up your volume before opening! For more on large aircraft
engines using the Otto cycle, click here.
Diesel Cycle Template
(New 5/28/2009)
This spreadsheet
provides a template for analysis of the Diesel (compression-ignition, internal combustion)
Cycle. The user must fill in the
data in the top grid. From that
data, the cells in the second grid are updated, and Pressure-volume and
Temperature-entropy diagrams are generated. This workbook includes the
capability of doing a sensitivity analysis.
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