Development Of Supervisory Control System For Condensation Heat Transfer Test-Board And Experimental Study

Film condensation heat transfer problems outside two-dimensional,three-dimensional fin tube, especially tube bundle are primarily solved by experimental methods.Since the requirements of high precision temperature control and large quantities of data to be collected and analyzed in the test, we need to develop a supervisory control and data acquisition system.This paper first introduces system principles and major equipments of condensation heat transfer test-board. Detailed needs analysis were carried out for the condensation heat transfer test.Hardware of the supervisory control system were developed,including independent temperature control sub system and data acquisition sub system,in order to meet the different requirements of sampling time.Then the monitoring layer including monitoring screen and Curve analysis window was completed by device configuration,database configuration,screen configuration and ActionScript in the configuration software,to achieve real-time data exchange, display, historical data storage and curve trend analysis.In Lab VIEW, through I/O communication to achieve the data exchange between software and hardware and between configuration software and LabVIEW.Temperature PID controller with gain schedule control and Smith Predictor control is developed by using PID and Fuzzy Logic Toolkit.Step response curves are plotted through experimental methods,as a result of no self-balancing capability,from which transfer functions are obtained. This paper designs a Smith Predictor scheme for no self-balancing capability object.Gain schedule control and Smith Predictor control are initially confirmed probability after simulation study-in Lab VIEW.Finally,after software and hardware debugging,the result of hot water temperature experimental study shows that gain schedule control is obviously improved in temperature overshoot and less regulation time than using PI control or PID control separately. Temperature overshoot is significantly reduced with PI control after Smith Predictor,and regulation time is much shorter with gain schedule control after Smith Predictor.By comparison,for the hot water temperature.using the gain schedule with Smith Predictor control strategy can obtain optimal control results with an accuracy of±0.1℃;. for the cooling water temperature,using the gain schedule control strategy can obtain better control results with an accuracy of+0.05℃.