Chemistry Reference
In-Depth Information
of the echo signal. Takeda (1986) investigated pipe and Taylor vortex
flows. He also applied the UVP technique for flow mapping in mercury
(Takeda, 1987).
A short overview of the UVP method including the signal processing
for the Doppler shift frequency estimation and application was given
by Lemmin and Rolland (1997). An extensive coverage of Doppler
ultrasound can be found in three textbooks (Jensen, 1996; Evans and
McDicken, 2000; Hill
et al.
, 2004) from the medical field, which de-
scribe many aspects also relevant for engineering applications of ul-
trasonic measurements. Also, Cobbold (2007) contains one chapter on
pulsed ultrasound for velocimetry.
3.1.3
Existing literature on UVP-based rheometry
An overview of the publications on ultrasound velocimetry-based
rheometry carried out by various research groups is given in the text
and Tables 3.1 and 3.2.
3
.
1
.
3
.
1
Polish Academy of Sciences, Warszawa, Poland
In his often overlooked publication, Kowalewski (1980) describes mea-
surements in suspensions and two different emulsion types with con-
centrations varying from 5 to 50% using a pulsed ultrasound-based
machine (Nowicki, 1979). The 'blunting' of the profiles as a function of
the particle concentration was characterised with a power law exponent
(Equation 3.18).
3
.
1
.
3
.
2
University Erlangen-Nurnberg, Germany
The idea of combining the velocity profile measured with ultrasound
and pressure drop for in-line rheometry was first mentioned by Brunn
et al.
(1993). In this publication actual rheometry data are only shown
for measurements where laser Doppler is used to obtain the veloc-
ity profile. Then, M uller
et al.
(1997) calculated shear rate-dependent
viscosities from simultaneous measurements of ultrasonic velocity pro-
files and pressure drop in a Newtonian glycerin/water solution, a non-
Newtonian aqueous polyacrylamide solution and a non-Newtonian hy-
droxypropyl guar gum solution. The velocity profile-based flow curves
(shear rate-dependent viscosity) were compared with those measured
using a rheometer. Later Wunderlich and Brunn (1999) also measured
a polyacrylamide solution and fitted the measured profiles with polyno-
mial, power law and Ellis fluid functions. Brunn
et al.
(2004) presented
results of UVP-PD measurements of a body lotion (concentrated sur-
factant solution).
