Jm. Ding et al., NUMERICAL-ANALYSIS OF LIQUID-SOLIDS SUSPENSION VELOCITIES AND CONCENTRATIONS OBTAINED BY NMR IMAGING, Powder technology, 77(3), 1993, pp. 301-312
Analyses of some of the steady-state, fully developed, and isothermal
carrier fluid velocity and solids concentration data of Altobelli et a
l. [1] and Sinton and Chow [2] obtained using three-dimensional time-o
f-flight nuclear magnetic (NMR) imaging techniques are presented in th
is paper. NMR imaging offers powerful techniques to nonintrusively det
ermine three-dimensional time-dependent velocity and concentration fie
lds to assist development and validation of the constitutive models an
d the computer programs describing concentrated suspensions. These exp
eriments were carefully performed and probably represent the best avai
lable open literature data of their kind. COMMIX-M, a three-dimensiona
l transient and steady-state computer program written in Cartesian and
cylindrical coordinates, has been used to analyze the NMR data. This
computer program is capable of analyzing multiphase flow and heat tran
sfer and utilizes the separate phases model wherein each phase has its
own mass, momentum, and energy equations. COMMIX-M contains constitut
ive relationships for interfacial drag, solids viscosities and stresse
s to describe the solids theology, and virtual mass and shear lift for
ces extended to a continuum from the single particle literature. Also
included is a solids partial-slip boundary condition to allow nonzero
tangential velocity at the tube walls. This computer program is being
developed at Argonne National Laboratory for application to test vario
us interphase interaction models and to predict design and processing
of dense fluid-solids suspension systems. Comparisons of computed and
measured concentration and velocity profiles provide some insights int
o the mechanisms governing the observed phenomena. Recommendations for
model improvement are given. To the authors'knowledge, these are the
first such comparisons of theory and experiment.