Alph is no longer for sale.

I am afraid revenue generated from Alph has not proven to be sufficient to justify its continued sale. I greatly appreciate the support of the folks who have purchased Alph in the past and hope that it will continue to serve you well in the future.

This and related pages will be maintained for archival purposes only.

Craig


Alph Case Study Example

From your iPhone, you can download the completed example

Goal

This case illustrates the use of the Case Study Tool to record some properties of a flashed fluid at a range of temperatures. This is about the simplest practical use of the case study tool, which can also be used to record the results of complex calculations involving many fluid and tools.

Fluids

There is only one fluid in this case:

feed
The same fictitious natural gas stream used in the tutorials, except its temperature is set by the formula.

#casestudy.x

Where casestudy is the eponymously named casestudy tool described below and "x" is its independent variable - i.e. the one that will be varied.

Variables

No variables are used in this example.

Tools

There is only one tool:

casestudy

This tool provides a range of temperatures for the feed fluid and records three arbitrary values of the liquid phase of the fluid at each temperature - the propane mole fraction, the propane molar flow and the viscosity.

The number of points is set to 30, which means the i value of the tool will take on values from 0 to 29. Thus the formula for X:

-60 + #.i * 5 ' Feed_T

would result in values from -60 to 85. Note that the first word of the comment, Feed_T in this instance, will be used as the name of the X value for the table and plot views.

The Y value formulas are

@feed.l.x:"propane" ' C3_Fraction

for the liquid phase propane fraction

@feed.l.x:"propane" * @feed.l.f ' C3_Flow

for the liquid phase propane flow

@feed.l.viscosity ' Liq_Viscosity

for the liquid phase viscosity

As with the X value, the first word of the comment will be used as the legend name in the table and plot views.

The Table button on the bottom tool bar must be tapped to initiate the calculation of the values and switch to the table view. Once the values have been calculated, you can switch between the various Y columns using the Prev and Next buttons. You can also use the Mail CSV or Mail TSV to send the complete table as a comma or tab separated value file attached to an email message. These files can then be imported into a spreadsheet program for further manipulation or display.

Once the values have been calculated, you can also tap the Plot button on the bottom tool bar to switch to a graphical view of the results. Each Y value is scaled to range from its minimum to maximum values. As you drag the graph around or zoom in or out with a pinch gesture, the values reported at the upper left always reflect the values under the cross hairs at the center of the screen.