Abstract: For the formation and influence of heat exchanger microbial fouling are complicated,the fouling resistance data and laws are more difficult. By using plate heat exchanger experimental system,the effect of Ca²⁺ on cooling water iron bacteria microbial fouling and water quality parameters(OD,pH,electrical conductivity) changes under different temperature and velocity was studied. Results showed that microbial fouling resistance was increased obviously with Ca²⁺ added in cooling water. With cooling water inlet temperature increase,the OD and the conductivity of iron bacteria is decreased gradually,and the pH is going higher,and the microbial fouling resistance is decreased correspondingly. With cooling water inlet velocity increase,the OD and the conductivity of iron bacteria were increased and pH was decreased in Ca²⁺ environment. But for the increasing velocity,the denudation to microbial fouling was enhanced and the microbial fouling resistance presents downtrend accordingly.

Key words: plate heat exchanger, water quality parameters, calcium ions, iron bacteria, fouling resistance

摘要： 换热设备微生物污垢形成机制和影响因素复杂，污垢数据和规律的获取难度较大。本文采用搭建的板式换热器循环冷却水实验系统，获得了加入Ca²⁺后板式换热器冷却水铁细菌微生物污垢热阻数据，研究了加入Ca²⁺后不同运行工况下冷却水水质参数（OD、pH、电导率）的变化，进一步分析了水质参数变化对微生物污垢生长带来的影响。结果表明，加入Ca²⁺后微生物污垢热阻渐变化明显。随着低温循环冷水进口温度增加，含有Ca²⁺和铁细菌的循环冷却水OD逐渐降低，pH则逐渐升高，电导率减小，微生物污垢热阻逐渐降低；随着流体速度的增加，循环冷却水OD则升高，pH降低，电导率增大，但流速的增大同样加剧了冷却水对通道壁面的剥蚀作用，导致微生物污垢热阻随流速增逐渐下降。

关键词: 板式换热器, 水质参数, 钙离子, 铁细菌, 污垢热阻