基于目标自寻优离心式污水泵汽蚀的模糊控制

【作者】 韩伟；

【导师】 李仁年；

【作者基本信息】 兰州理工大学 ， 流体动力与控制工程， 2003， 硕士

【摘要】 离心式污水泵(即污水提升泵)，是典型的以输送固液两相流为主，同时含有不定量气体的多相流流体机械。污水提升泵输送污水的一个重要特点就是来流工况的不稳定，所以在污水泵的选型和安装上就存在着许多不确定因素，导致其在长期的运行过程中形成很严重的汽蚀破坏。汽蚀破坏一直是污水处理系统中长期没有得到解决的问题。 考虑到如果为了尽量在小流量和大流量工况区以及不同污水成分情况下避免汽蚀的发生，则泵吸入口的压力与输送液体的汽化压力就要保持很大的差距，这将造成很小的允许吸上高度或过大的倒灌高度和泵选型方面的失误。致使选型和安装不能同时满足污水泵站系统运行可靠性与效率的统一，因此对已经发生汽蚀的即定污水泵运行工况进行调节就成为控制和减轻污水泵汽蚀破坏的新途径。 就这个问题，本文首先分析了离心式污水泵汽蚀发生与调控的影响因素，对泵汽蚀的传统控制方法进行了总结；其次讨论了离心式污水泵变速调节工况与汽蚀性能的关系，然后针对污水泵汽蚀调节缺乏精确的数学模型以及调节控制过程的强非线形、滞后性和控制目标的不确定性等特点，提出了将模糊控制理论结合自寻优算法应用在污水泵汽蚀的控制系统方面的新思路。最后对整个控制系统在MATLAB中的SIMULINK环境下进行了仿真实验。实验表明该方法可以在一定范围内对汽蚀程度进行有效的控制。更多还原

【Abstract】 The centrifugal sewage pump is the typical multi-phase flow fluid machinery, which is mainly used to transport and lift solid-liquid two-phase flow including a certain extent of gas. As an important character of sewage transportation by pump, the flow condition of sewage is so unstable that many uncertain factors including the selection for pump type and installation result in serious cavitations damage during the course of the pump long-term running. Cavitations damage is an unresolved problem in the sewage treatment system up to now.If cavitations are avoided as possible in the condition of the lower-capacity or large-capacity and heterogeneity of the sewage, the much difference between the pump suction pressure and the vapor pressure of the sewage must be retained, which will result in such erection error as very lower allowable suction head or very high negative suction head and the invalidation of the selection of pump type. Thus the selection of pump type and the installation cannot be satisfied with the unitive relation between the efficiency and reliability in the sewage treatment system at the same time. So the work condition regulation becomes a new way to control or mitigate the cavitations damage for ihe certain sewage pump, which has occurred cavitation.To the question, such work had been done in this paper as follows. First the influencing factors of the cavitation occurrence and control for the centrifugal sewage pump have been analyzed and the traditional ways to controlling cavitations damage for pump are summarized. Second the relation between various rotating speed regulation of the pump operation and cavitations performance has been discussed. Third the new idea about fuzzy control integrating with self-optimization arithmetic has been used to control the cavitations damage for the cavitation control being short of accurate mathematical model, certain control aim and the control properties including strong nonlinear effects, hysteresis effect etc. In the end the whole cavitation control of sewage pump was simulated in the SIMULINK environment on MATLAB. The simulation experiment shows that the new way can control a certain extent of cavitation of sewage pump effectively.更多还原