Chemistry Reference
In-Depth Information
R
v
r
r
R
*
P
1
P
2
L
∆
P
Fig. 3.1
Pipe flow velocity profiles with the geometric sizes used in Equations 3.14 to
3.23. The typical profiles for Newtonian (n
=
1), power law shear thinning (n
<
1), power
law shear thickening (n
>
1) and Herschel-Bulkley with plug radius R
*
are shown from left
to right.
having a continuous product quality monitoring. In addition, it becomes
possible to measure under conditions (pressure, temperature, shear
history) not reproducible in a conventional rheometer, and it allows to
measure suspensions containing particles of a size that would not fit in
a conventional rheometer gap.
In spite of all those advantages and four completed doctoral works on
the topic since 1993, there is still no known commercial installation of
a UVP-PD-based in-line rheometer in the industry. This is probably due
to several reasons: the fact that many components are yet custom-made
and that for a successful implementation know-how is needed in the
fields of acoustics, electronics, software programming, signal process-
ing, ultrasound transducers and of course rheology. So this chapter tries
to give an overview of the technique and describes the single compo-
nents of the measurement system from the transducer to the rheometry
calculations.
Another interesting application of ultrasound velocimetry, not further
described here, is the measurement of the flow profile in the gap of a
rotational rheometer described by Manneville
et al.
(2004, 2005) and
Sandrin
et al.
(2001).
3.1.2
History of ultrasonic velocimetry
Historically, the development of the Doppler velocimetry started in
the medical field in the 1950s (Satomura, 1957) with continuous wave
devices. The first pulsed range gate systems were introduced at the
beginning of the 1970s (Wells, 1969; Baker, 1970; Brandestini, 1978;
Peronneau, 1992). Outside the medical field, ultrasonic velocimetry
was applied to measurements of liquid metal flow by Fowlis (1973),
using continuous wave ultrasound, while Pinkel (1979) utilised pulsed
ultrasound at low frequencies to measure ocean currents. Garbini
et al.
(1982a, 1982b) characterised turbulence using the spectral broadening
