THE COAGULATION RATE OF SMALL PARTICLES IN SETTLING FLUID SUSPENSIONS

By solving the compete equation for the pair-distribution function in the case of large and small Peclet number, the rate of the coupled Bro wnian and gravity-induced coagulation of small particles suspended in a Newtonian fluid has been obtained. It is shown that the Swift and Fr iedlander's additivity assumption is not valid in these regimes. Based on the above work and using interpolation method, the complete pictur es of the dimensionless coagulation rate Nu (Nusselt number) as a func tion of the dimemionless parameter Pe (Peclet number) are now obtained . The dependences of Nu curves on the size ratio I and reduced density ratio gamma of the two spheres, and the numerical errors of Nu calcul ated by the additivity assumption are also discussed.