板式换热器混合微生物污垢特性的实验研究

为探讨铁细菌与黏液形成菌混合微生物污垢的结垢特性，进而为微生物污垢阻垢和抑垢的研究打下基础。本文以微生物污垢中最常见的铁细菌和黏液形成菌为研究对象，实验研究了板式换热器中两种细菌在形成混合微生物污垢时相互协同抑制的关系以及不同工况下的结垢特性。结果表明，微生物污垢存在明显诱导期，铁细菌的污垢热阻渐近值约为2×10^-4m²·K/W，黏液形成菌的污垢热阻渐近值约为1.2×10^-4m²·K/W，铁细菌相比黏液形成菌有较强的致垢能力，1∶1比例混合菌的热阻值介于二者之间；无论哪种细菌量占据主导时，它们之间的互相协同作用会促使混合污垢的致垢能力增强。30℃时混合菌的热阻渐近值低于35℃时的情况，达到渐近值的时间约为35℃时的2倍；流速对混合菌污垢特性的影响明显，流速为0.1m/s时的污垢热阻渐近值约为0.15m/s时的2倍，达到渐近值的时间约为0.15m/s时的2.7倍。

Experimental study on composite microbial fouling characteristics of the plate heat exchanger

In order to study the characteristics of composite microbial fouling and the method of restraining fouling in the future, we chose iron bacteria (IB) and slime-forming bacteria (SFB) as the research objects which are the most common in microbial fouling. An experimental study was carried out on the plate heat exchanger for the relationship of the two bacteria in the composite microbial fouling formation and the fouling characteristics under different conditions. The results show that the microbial fouling has obvious induction period. The asymptotic value of fouling resistance of the iron bacteria is 2×10^-4m²·K/W, and the asymptotic value of fouling resistance of the slime-forming bacteria is 1.2×10^-4 m²·K/W. The iron bacteria have strong ability of fouling formation than the slime-forming bacteria. The fouling resistance of mixed bacteria with the proportion 1:1 is between the two above. No matter what kind of bacteria occupy the main volume, synergistic effects between the two kinds of bacteria prompt the ability of the fouling formation. The asymptotic values of fouling resistance of the mixed bacteria in 30℃ is lower than it in 35℃, and the time get to stabilization is twice that of 35℃. The velocity has obvious effect on the composite microbial fouling characteristics. The asymptotic values of fouling resistance of the mixed bacteria in 0.1m/s is twice that of 0.15m/s, and the time get to stabilization is 2.7 times that of 0.15m/s.