一种深海中温菌胞外多糖水溶液的流动行为

Flow Behavior of Aqueous Solution of Exopolysaccharide Secreted by a Deep-sea Mesophilic Bacterium

研究了一种深海中温菌Wangia profunda(SM-A87)胞外多糖(EPS)稀溶液在德国Haake RS75流变仪Z41 DIN同轴圆筒转子系统中的剪切流动行为,考察了溶液浓度、温度、pH值及NaCl浓度对雷诺数(Re)和临界雷诺数(Rec)的影响.结果表明,随着溶液浓度的增大,Re逐渐减小而Rec逐渐增大;随着温度的升高和NaCl浓度的增大,Re逐渐增高而Rec逐渐降低;在pH=3～12内随着pH值的增加,Re和Rec开始基本保持不变,当pH>7后Re逐渐增加而Rec逐渐降低.Rec与温度的关系符合Arrhenius-like方程,与体系黏度间存在幂率关系.

Shear-induced flow behavior of aqueous solution of exopolysaccharide（EPS） secreted by a deep-sea mesophilic bacterium（SM-A87） was investigated in a coaxial cylindrical measurement system（Z41 DIN） used in the Haake RS 75 Rheometer（Germany）,and emphasis was placed on the influence of solution concentration,temperature,pH value and NaCl concentration on Reynolds number（Re） and critical Reynolds number（Re c） of the solution.The results showed that Re decreased but Re c increased gradually with solution concentration inereasing or temperature and NaCl concentration decreasing.As pH value increased from 3 to 12,Re and Re c were initially almost constant,but at pH value higher than 7,Re increased accompanied with Re c decreasing.The relationship between Re c and temperature were fitted well by an Arrhenium-like equation while that between Re c and solution concentration by a power law model.