论文部分内容阅读
利用天然水通过管壳式模拟换热器来动态模拟冷却水系统的流动传热和污垢形成过程,实验中恒定壁面材料、加工方式和流速、水温等运行参数,突出研究水质参数对污垢形成的影响。文中基于污垢形成机制的初步认识,定性分析了硬度(钙、镁离子)、碱度、pH值、溶解氧、浊度、铁离子浓度等水质因素对污垢形成的影响,将其和时间作为输入量,污垢热阻作为输出变量,建立基于支持向量机的冷却水污垢热阻预测模型,并以另一运行周期数据检验模型预测精度,计及实验系统的不确定度,平均误差为8.874%;与美国管壳式换热器制造商协会(Tubular Heat Exchanger Manufactures Association,TEMA)标准推荐数据相比,本法所得污垢特性内涵更丰富,热阻除其渐近值,还有时变性;可靠性增强,逼真度高;可操作性强。
Natural water is used to dynamically simulate the flow and heat transfer of the cooling water system and the fouling process through the shell and tube heat exchanger. The constant wall material, processing method, flow rate and water temperature are used to highlight the effects of water quality on fouling influences. In this paper, based on the preliminary understanding of the mechanism of fouling formation, qualitative analysis of the impact of water quality factors such as hardness (calcium and magnesium ions), alkalinity, pH value, dissolved oxygen, turbidity and iron ion concentration on the fouling was made. Volume and fouling resistance as the output variables, a prediction model of fouling thermal resistance of cooling water based on support vector machines was established. The model prediction accuracy was tested with another operating cycle data, and the uncertainty of the experimental system was taken into account. The average error was 8.874%. Compared with the standard recommended data from the American Tubular Heat Exchanger Manufacturers Association (TEMA), this method has more substantial soil characteristics, thermal resistance besides its asymptotic value, and time-dependent reliability. , High fidelity; maneuverability.