Speaker 1: SOLIDWORKS Flow
Simulation has several
additional modules each which
add even more capability to our
already powerful CFD package.
All of these modules are
embedded inside the existing
SOLIDWORKS Flow Simulation
interface, keeping the software
dynamic and easy to use. Here
we're going to look at the
heating ventilation and air
conditioning module or HVAC for
short. Typically the environment
studied in this module will be
anywhere people or sensitive
equipment were present, or
perhaps where radiation is going
to be a major factor. So
anything from a kitchen where
humidity and condensation may be
an issue to a data center to
size the appropriate fans and
ensure the servers are
adequately cooled and evenly
cooled or perhaps a large glass
structure where not considering
radiation is going to cause a
major issue. In this first
example, we're going to look at
a section of an airplane. This
is to ensure there is enough
circulation of clean air and any
contaminants are removed while
maintaining a comfortable and
appropriate temperature.
Firstly, we set up our flow
simulation as normal using the
familiar boundary conditions and
heat sources, Here we can see
all the people have a
temperature applied. The inlets
can be seen at the top of the
model and the outlets at the
base. Once this is complete, we
can then run the study. We can
then use the industry standard
ISO 7730 comfort parameters to
see what percentage of people
will be unhappy with
this draft from the air
conditioning system. Since the
HVAC module is embedded, we can
use all the familiar flow
simulation tools such as this
cut plot, which shows us any
areas in red where the velocity
may be slightly too high, or the
draft may be slightly too
strong. So this percentage of
people will be unhappy with that
particular draft. Next we can
see what percentage of people
will be happy with the overall
temperature. We can do this by
looking at the predictive mean
vote or PMV for short. This
result parameter is based on
social studies and considers the
average thermal sensation of a
group of people. The target here
is to get to zero, but that is
the neutral aim and the ideal
scenario, however, three would
be uncomfortably and minus three
will be too cold or drafty. As
with all SOLIDWORKS flow
simulation results. We can
quickly and easily change the
plot. We can change the scale of
the legend to help us better
understand the results. And then
we can quickly investigate
further using the probe tool.
From this we can quickly and
easily see the gentleman at the
back is probably going to be too
cold so we can look to adjust
the air conditioning system
accordingly. But beyond this, we
could also look at the quality
of the air and see how long it
has been in the system for. We
can do this by using the local
mean
age plot for LMA For short.
Here, we can see the extra
ventilation might be needed in
this area to help remove the
stagnant air from the system.
Another way for us to check the
effectiveness of our system
would be to look at the CRE or
contaminant removal
effectiveness parameters. These
parameters are an index that
provide information on the
effectiveness of a ventilation
system on removing contaminated
air from the entire space. For a
perfect mixing system our value
of one is very good. And at the
end below one is classed as poor
but we could take this a step
further. For example, what would
happen if one of these
passengers sneezed ideally would
like the contaminants to be
forced down away from the other
passengers, straight into the
outlets and into the filters.
But see if this happens in
practice, we can run a tracer
study where a set amount of
contaminant or add mixture is
placed into the existing flow
stream. We can then see which
areas will be affected by this.
Here we can use this cut plot to
see where this would travel. In
this example, it's safe to say I
wouldn't like to be sat by and
this gentleman, but beyond this,
we can study multiple traces in
one study so we can clone the
tracer and then release more
contaminants into the air to see
what would happen over the time
period, and work out how we can
best modify our air conditioning
system to suit. But as well as
these comfort parameters, traces
studies and the advanced
material library, one of the
other main features of the HVAC
module is the advanced radiation
method. Usually SOLIDWORKS Flow
Simulation uses a discrete
transfer method, which is great
for most studies, electronics
cooling or turbulent flow
problems. However, in this case,
we have a large glass structure
which will be exposed to solar
radiation. This method is much
more capable and means we can
consider geometric optical
effects such as shadows, the
method we are using here is
called discrete ordinance. This
is required when studying
semi-transparent materials such
as glass, because it allows for
absorption. So certain of wave
lengths will be allowed to pass
through and other wave lengths
will be absorbed by the
material. The HVAC module comes
with a comprehensive building
materials library with this
information already added in on
top of this, we already had a
predefined list of locations
around the world complete with
solar information. This library
also includes an enhanced fan
database to help you quickly and
accurately specify the boundary
conditions with real
manufacturer's data. However, if
the radiation in your study,
isn't solar, the HVAC module has
other tools which will allow you
to apply radiation to a
particular surface or volume. We
can do this either as a
diffusive or directional source
by selecting either power,
intensity or temperatures and
input all of these tools, help
users getting great insight into
the designs. Sometimes
even more so than a physical
test for more information on
this module or anything else,
please don't hesitate to get in
touch.