Research On Automatic Temperature Control System Based On Heat Exchange

As an important equipment that can realize heat transfer,heat exchanger is widely used in various industrial sectors.There is great significance for the effective use of energy and energy conservation by improving the heat exchange efficiency of the heat exchanger and rationally organizing its heat exchange process.Therefore,based on the internal heat transfer mechanism of the plate heat exchanger,this thesis studies the control of the outlet working fluid temperature by researching its dynamic heat transfer characteristics,so as to ensure the safe and smooth production process and reduce energy waste.Firstly,in view of the problem that the current heat exchanger model is not accurate enough to correctly reflect the actual heat exchange process,the production process of water vapor heating chemical crafts is divided into no phase change and phase change conditions,and their simulation models are established respectively.For the case of no phase change,the Euler description method is used to divide the heat exchanger flow channel into grid micro-elements,and the finite difference method is used to solve the problem numerically.The results show that the model can better describe the dynamic heat transfer process inside the heat exchanger.For the phase change condition,the Lagrange description method is used to track a single fluid particle,study and record the change law of each state quantity of the particle.The results show that the model can dynamically capture the information of different phase states of water vapor in the flow channel,and it can effectively solve the problem of difficult to determine the position of the phase transition point.Secondly,in order to solve the problem that the outlet temperature of the heat exchanger is difficult to control and the adjustment effect is poor,a temperature control method based on the improved sparrow search algorithm is proposed.By introducing the idea of chaotic iterative mapping into the traditional sparrow algorithm,the sparrow population is initialized and the global search ability of the algorithm is improved.And the performance of the algorithm is analyzed and tested by using the standard test function.The results show that the improved algorithm has better performance in optimization.Therefore,the improved sparrow search algorithm is used to tune the parameters of the PID controller in real time online,and an automatic temperature control system for the heat exchanger is designed.Finally,simulation experiments are carried out on the constructed temperature control system under two conditions of cold start and steady state disturbance.And compared with the experimental results of no control strategy and PID control to verify its superiority.The experimental results show that the heat exchanger temperature control system has good steadystate and dynamic performance,and can meet the requirements of fast and accurate control of the outlet temperature of chemical crafts.At the same time,in order to improve the automation level of the heat exchanger,according to the interface requirements of the actual heat exchange conditions,in the Visual Studio 2019 software,a friendly control system interface is designed by using the MFC application development framework,which not only can realize parameter setting,but also more intuitively display the operating status of the system for data analysis and comparison.