Tech Briefs Magazine - October 2021 - 40a

DESIGN OPTIMIZATION
team was able to propose a
highly sensitive device that
performs well, even for slight
variations in gas flow rates.
» TURBINE METER
WITH VANES
FIGURE 4 
   
   
  
 
   
components, thus assuring the
mechanical ruggedness and
integrity of the system.
FIGURE 5  
   
  
  
 
40a COMSOL NEWS
Intro
Cov
ToCToC
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» MÖBIUS BAND
TURBINE METER
The next design consists of a
Möbius band turbine, where
the rotation of the turbine
is used to measure the gas
flow rate. These gas meters
measure the gas volume by
determining the velocity of
the gas moving through the
Möbius strip. The Möbiusband-shaped
rotor is placed
in the way of the gas flow
passing over it, which rotates
the shaft. The output of the
shaft is transferred to a bevel
gear system. The turbine infers
the velocity of the gas, which
is transmitted mechanically to
an electronic or mechanical
counter. The Raychem team
modeled the turbulent gas
flow (Figure 3) as well as the
stresses and torque developed
in the turbine.
It is important to note that
the Möbius band turbine gas
meter performs well when
the gas flow rate is high. Since
the gas volume is determined
by its flow, the efficacy of
the device is limited while
measuring flow with a low
pressure drop. To circumvent
this issue, the Raychem team
designed another flowmeter
based on a well-known
principle: Magnets of the
same polarity repel each other.
» TURBINE METER
WITH MAGNET AND
BALL/DISC DESIGN
In the third meter design, an
object, typically a ball or a disc,
is arranged inside the pipe in
such a way that the magnetic
force causes it to float. The
object gets lifted with the flow
of gas in the pipe, and the
gas flow is measured by the
height to which a magnetic
plate rises. This kind of meter
is highly sensitive and can
measure even a small pressure
drop. The researchers studied
the magnetic properties and
device performance and
arrived at an optimized design
(Figure 4). In this case, the
The final design is also based
on the rotation of a turbine,
but a different turbine design
is used. Here, the turbine
assembly with fixed guide
vanes and runner vanes is
placed in the main channel as
an obstructing element (Figure
5). The energy captured by
the rotating turbine is used
to energize the thermal
sensors, hence making this
device a self-energizing
system. The guide vanes act
as a nozzle, channeling the
gas flow toward the runner
vanes, which rotate the shaft
and bevel gear pair. Gas flow
is measured based on the
rotation of the bevel gear pair
or by measuring the drop in
temperature using thermal
sensors. The simulation
studies enabled the Raychem
team to design a smart
energy gas meter with only a
U-shaped tube and a sensor
in the housing, making it very
compact and easy to install.
» FUTURE
RESEARCH PLANS
Validated simulation results
are at the core of Raychem's
four new gas meter designs.
The Raychem team is
confident in the performance
of these flowmeters to suit the
requirements of domestic and
industrial applications. These
designs have been shortlisted
for production and should
soon be available to urban
consumers across India, to be
installed directly inside the gas
meters fitted in their homes.
ACKNOWLEDGEMENTS
The Raychem team would like
to acknowledge Tito Kishan
for assisting in TRIZ application
and Ganesh Bhoye for design
engineering.
➮
http://info.hotims.com/79418-936
Tech Briefs Magazine - October 2021

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