Projeto e desenvolvimento de uma bancada didática de testes para análise de troca térmica e estabilidade do sistema de controle

Abstract

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.