Transient reactor example

Here we make some substitutions for a transient reaction example.  At time =0, the feed compositions of qa and qb are set to caf= .1, and cbf = .2.  The flow rates are qa=10 and qb=10 and the exit is set to q = 20 so no volume change occurs in the reactor.  We expect that this example will have a transient period leading to a steady state.

Here the numerical ODE package solves them.

The command to plot an "interpolating function" requires the "Evaluate" command.  In this figure we are plotting the concentrations  a,  b, and  d as a function of time from the solution "ans1".

We see that the concentrations reach a steady state.  The highest one is "B", "A" is next and the product is lowest.  

return to conclusions

Additional calculations for this part

As was mentioned above the behavior is a simple transient leading to a steady state.  For your interest you could:

1.  Vary some of the numbers to see how the transient time varies with the flow rates, reactor volume and reaction rate.

2. Change the form of the reaction expression to see its effect.

3.  Nondimensionalize the expression to find the dimensionless groups and use the values of the groups to note the relative importance of the reaction on the time scale of the transient.