【摘要】 为了在实验室内精确的模拟各种冷却试验,研制了采用抽风式机械通风结构的逆流式模拟冷却塔,介绍了该塔的整体结构和工作原理;以流量或温度作为被控对象,可以近似看作一阶惯性滞后模型,在获得对象的飞升曲线后,用Cohn-Coon公式求对象参数,在最小模型假设的前提下,由Ziegler-Nichols整定法结合人工整定得到PID参数;测试实验中水温和风温稳定后都可控制在设定值的±0.1℃,实验结果表明,该冷却塔设计合理,控制精度高,能够满足各种冷却试验使用要求。更多还原

【Abstract】 In order to simulate a variety of cooling experiments accurately in the laboratory,a reverse-flow type analog cooling tower,adopting exhaust fan as its mechanical ventilation structure,is developed.The integral structure and working principle of the tower are introduced.The system can be approximately considered as a first-order model with dead time.The parameters of the model are determined by the Cohn-Coon formula after obtaining the step response curve of the controlled objects.Under the precondition of minimal model,PID parameters are acquired by using Ziegler-Nichols tuning method and artificial tuning.After the water temperature and wind temperature are stable in the experimental field,they can be controlled in the set value±0.1℃.The experiments show that the cooling tower is reasonably designed,having high control precision and can satisfy all kinds of cooling experiment needs.更多还原