Resumo:
This work describes a didactic test rig both for simulation of a control system
and for studies thermal exchange in a shell and tube type heat exchanger enabling
simulation of several configuration of flow currents. Another aspect and purpose of the
test rig is the possibility to study and analysis of the dynamic behavior of the heat
exchanger temperature control using a frequency inverter as final control element
instead of the conventional control valves for controlling the flow rate. Several
temperature measurements in the inlets and outlets of the heat exchanger have been
executed, allowing the obtainment of the overall heat transfer coefficients for concurrent
and countercurrent flows. These results were compared with the theoretical ones
calculated with the heat exchanger dimensions, fluid and flows characteristics. Related
to the control system, a temperature control optimization has been executed by using the
Ziegler-Nichols limit sensitivity of tunning method. Using the graphic resources of the
used supervisory software, the static and dynamic characteristics of the process were
obtained for the elaboration of the system mathematical model and than the simulation
with the Simulink software, were made, using the same tunning method. An analysis of
the results have shown a good agreement between experiments and theory for both the
thermal and the control viewpoint. An analysis of the obtained results is presented
showing good agreement between the experimental and theoretical approach for both
thermal and control system treatment. Also, some suggestions for future studies
exploring the available and possible resources of the test rig are presented.
