ESTIMATION OF SETTLING VELOCITIES

This paper deals with settling velocities estimation, which is of majo r importance as settling velocities estimation is a prerequisite for p roperly dimensioning settling tanks. Several measurement procedures ar e presented and analyzed here. A general framework for identification which includes modelisation of the settlers and identification techniq ues is developed hers-in. In this paper, we demonstrate that for a par ametric set of settling density functions rho(d nu) = Sigma(i=1)(N) th eta(i)rho(i)(d nu) the mathematical relation between the measures M(t( i))(i)=(1,N) and the unknown quantities (theta(i))(i=1,N) take the fol lowing linear form M(t(i)) = Sigma(k=1)(N) theta(k)integral(R)phi(x)(t (i), nu)rho(k)(d nu) This relation makes it possible to have access to statistical errors in settling velocity estimates (theta(i)) in assum ing that a statistical model of measurement errors (M(t(i))) exists. T he consequences of the choice of sampling times (t(i))(i)=(1,N) on the quality of the estimation are also investigated. (C) 1998 Elsevier Sc ience Ltd. All rights reserved.