Biomedical Engineering Reference
In-Depth Information
Figure 6.53
Proteins purification by size-exclusion chromatography.
is done. A secondary flow, miscible with the first one, flowing at a larger flow rate,
confines the first flow.
Let us analyze the case of flow focusing along a wall and denote
Q
1
and
Q
2
as the two flow rates, with
Q
as the total flow rate
Q
1
+
Q
2
and
w
1
and
w
2
as the
two channel widths occupied by fluid 1 and fluid 2, as schematized in Figure 6.59.
After a short establishment length, the new profile is a Poiseuille-Hagen quadratic
profile. Clearly, the relative width
e
=
w
1
/
w
is related to the flow rate ratio
Q
1
/
Q
.
Using (2.47) for the flow in a rectangular channel
Figure 6.54
Separation principle of substance traveling through a chromatography column.
