Abstract: 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.

Key words: Reynolds number, Sea mesophilic bacterium exopolysaccharide(SM-A87 EPS), Rheology, Laminar flow, Turbulent flow