Web app experiment 3 demonstrates feedback control of temperature during reaction in a continuous stirred tank reactor (CSTR). See the Resources tab, Web app experiments. Below is a static screenshot – click to enlarge.
At default conditions in manual control mode with constant inputs, the system oscillates. Do you know why the system oscillates? See the Resources tab, CRE Notes, 15 – CSTR thermal effects. Then put the system into Auto Control mode.
The architecture we are using is that of separate code objects, representing separate process units, which send messages to each other. This architecture allows us to change a simulation easily by adding or subtracting units from a system model.
These dynamic simulations solve a set of coupled, first-order, ordinary differential equations. This type of system is termed an “initial value problem.” The solution method is stepping in time (the independent variable here) using the Euler method. The Euler method has inherent numerical errors, as do other numerical methods, but the solutions can be corrected to approach the exact solution, as we have done in several labs in the desktop Reactor Lab.