Page 255 - Excel for Scientists and Engineers: Numerical Methods

232 EXCEL NUMERICAL METHODS

If Err.Number = 13 Then
On Error GoTo 0 'Disable the error handler.
Resume ptl 'and continue execution.
Else
End 'Some other error, so quit completely
End If
End Sub
Figure 10-9. Fourth-order Runge-Kutta custom function
for systems of differential equations.
(folder 'Chapter 10 Examples', workbook 'ODE Examples', module 'RungeKutta3')

Figures 10-1 0, 10-1 1 and 10- 12 illustrate the use of Runge3 to simulate some
complex chemical reaction schemes. Figure 10-1 0 shows concentration vs. time
for the consecutive first-order reaction scheme
A+B+C

for which the differential equations are

(1 0-24)

(1 0-25)

(1 0-26)

0.005 1

$ 0.004
E
i
.p 0.003
5
*
C
3 0.002
s
S
>
0.001
I -
0.000
0 2 4 6 8 10
time, seconds

Figure 10-10. Runge-Kutta simulation of consecutive
(folder 'Chapter 10 Examples', workbook 'ODE Examples',