The flow of a suspension through a bifurcating channel is studied experimentally and by computational methods. The geometry considered is an ‘asymmetric T’, as flow in the entering branch divides to either continue straight or to make a right angle turn. All branches are of the same square cross-section of side length
$D$
, with inlet and outlet section lengths
$L$
yielding
$L/D=58$
in the experiments. The suspensions are composed of neutrally buoyant spherical particles in a Newtonian liquid, with mean particle diameters of
$d=250~\unicode[STIX]{x03BC}\text{m}$
and
$480~\unicode[STIX]{x03BC}\text{m}$
resulting in
$d/D\approx 0.1$
to
$d/D\approx 0.2$
for
$D=2.4~\text{mm}$
. The flow rate ratio
$\unicode[STIX]{x1D6FD}=Q_{\Vert }/Q_{0}$
, defined for the bulk, fluid and particles, is used to characterize the flow behaviour; here
$Q_{\Vert }$
and
$Q_{0}$
are volumetric flow rates in the straight outlet branch and inlet branch, respectively. The channel Reynolds number
$Re=(\unicode[STIX]{x1D70C}DU)/\unicode[STIX]{x1D702}$
was varied over
$0<Re<900$
, with
$\unicode[STIX]{x1D70C}$
and
$\unicode[STIX]{x1D702}$
the fluid density and viscosity, respectively, and
$U$
the mean velocity in the inlet channel; the inlet particle volume fraction was
$0.05\leqslant \unicode[STIX]{x1D719}_{0}\leqslant 0.30$
. Experimental and numerical results for single-phase Newtonian fluid both show
$\unicode[STIX]{x1D6FD}$
increasing with
$Re$
, implying more material tending toward the straight branch as the inertia of the flow increases. In suspension flow at small
$\unicode[STIX]{x1D719}_{0}$
, inertial migration of particles in the inlet branch affects the flow rate ratio for particles (
$\unicode[STIX]{x1D6FD}_{\mathit{particle}}$
) and suspension (
$\unicode[STIX]{x1D6FD}_{\mathit{suspension}}$
). The flow split for the bulk suspension satisfies
$\unicode[STIX]{x1D6FD}>0.5$
for
$\unicode[STIX]{x1D719}_{0}<0.16$
while
$\unicode[STIX]{x1D719}_{0}=0.16$
crosses from
$\unicode[STIX]{x1D6FD}\approx 0.5$
to
$\unicode[STIX]{x1D6FD}>0.5$
at
$Re\approx 100$
. For
$\unicode[STIX]{x1D719}_{0}\geqslant 0.2$
,
$\unicode[STIX]{x1D6FD}<0.5$
at all
$Re$
studied. A complex dependence of the mean solid fraction in the downstream branches upon inlet fraction
$\unicode[STIX]{x1D719}_{0}$
and
$Re$
is observed: for
$\unicode[STIX]{x1D719}_{0}<0.1$
, the solid fraction in the straight downstream branch initially decreases with
$Re$
, before increasing to surpass the inlet fraction at large
$Re$
(
$Re\approx 500$
for
$\unicode[STIX]{x1D719}_{0}=0.05$
). At
$\unicode[STIX]{x1D719}_{0}>0.1$
, the solid fraction in the straight branch satisfies
$\unicode[STIX]{x1D719}_{\Vert }/\unicode[STIX]{x1D719}_{0}>1$
, and this ratio grows with
$Re$
. Discrete-particle simulations employing immersed boundary and lattice-Boltzmann techniques are used to analyse these phenomena, allowing rationalization of aspects of this complex behaviour as being due to particle migration in the inlet branch.