Oxygen transfer and shear rate in surface aerator.
Shear rate in a surface aeration system exerts a profound effect on its performance, affecting the mixing pattern, the power requirement and oxygen transfer process. Based on theoretical analysis, it is shown that the shear rate gamma in the fluid is a function of the rotational speed N of the impeller in surface aeration systems. Analysis shows that the shear rate varies linearly with N in laminar flow and its behaviour is non-linear in a turbulent flow regime. Experimental correlations of gamma with N have been developed in the present study for different sized surface aerators. Scale-up or scale-down criteria for oxygen transfer rate have been developed, which relate oxygen transfer rate to shear rate in surface aeration systems.
Indian Institute of Science, Bangalore, India. bimk@civil.iisc.ernet.in
Bimlesh
B
Kumar
Achanta Ramakrishna
AR
Rao
D003198:Computer Simulation; D004058:Diffusion; D008956:Models, Chemical; D010100:Oxygen / Q000737:chemistry*; D012212:Rheology / Q000379:methods*; D033081:Shear Strength; D014867:Water / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
D014867:Water; D010100:Oxygen