Optimization Of Monitoring And Controlling System In High-temperature Gas-solid Two-phase Flow Wind Tunnel Application

The main contribution of this paper is the optimization of monitoring and controlling system in high-temperature gas-solid two-phase flow wind tunnel application. The wind tunnel established by Institute of Thermal Power Engineering of Zhejiang University is a key project of the university. In order to ensure the feasibility of laboratorial system, a dependable monitoring and controlling system is necessary. The emphasis of this paper is that through optimizing the monitoring and controlling system which is based on the original one, the monitoring and controlling system of high-temperature gas-solid two-phase flow wind tunnel is able to run safely and steadily.Wind tunnel monitoring and controlling system uses a personal computer (PC) as the host computer; the Asia-control Technology Co., Ltd. Kingwiew as the Host Computer Software; the low computer adopts a programmable logic controller(PLC) with STEP7 as its software. Host computer and lower computer communicate through MPI card, then a small-scale distributed control system (DCS) formed. Host computer is mainly used for human-computer interaction and data monitoring. The operator can observe real-time data of the wind tunnel from the host computer interface, and send commands through the mouse and keyboard to fulfill the control functions. Lower computer is in charge of data collection, operation and output. It's an important component of monitoring and controlling system.This paper redesigned host computer interface, which is composed of the login interface, the main interface and a series of control interface. The main interface contains a lot of data and many buttons which link to other control interface. Lower computer enhances interlock protection, improves data input and output, adds velocity calculation. Automatic control of four main parameters (negative pressure, temperature, flow rate, concentration) in wind tunnel is achieved.Most of thermal processes have complex features, such as large time delay and time-varying. As a result, PID parameter tuning usually takes a long time.Genetic Algorithms is a biomimetic self-optimizing random algorithm, with the feature of parallel computing and global convergence. So it is applied to optimize the parameter of the PID controller in high-temperature gas-solid two-phase flow wind tunnel. By using the Matlab software, simulation on PID parameter tuning based on genetic algorithm is carried out. Real-running results show that PID parameter tuning based on genetic algorithm can get satisfactory results. This parameter tuning method can also be applied to other automatic control loop.