Download Identify supply to establish a predefined profile of temperature with Flux CF CN66

CEDRAT News - N° 66 - June 2014
Identify supply to establish a predefined profile of
temperature with Flux®.
Cyril Favre - CEDRAT.
M
acros have been available with Flux since 2008. Macros
allow sets of commands to be executed using PyFlux
command language, after questioning the user. The
questions can include the possibility to graphically select
Flux components such as points, face regions, etc. as well as
existing files opening a windows explorer. The goal of a macro
is to automate tasks, making Flux easier to use and to add new
functionalities.
&ŝŐƵƌĞϯ͗/ŶƉƵƚŽĨ
ƚŚĞŵĂĐƌŽ͘
In this part, we will present two macros available for induction
heating process. These macros can be used for steady state AC
application coupled with transient thermal application. The results
of the macros applied on a test case will also be presented.
The magneto-thermal test case represents a pipe heated with
an inductor composed of solid conductors. The inductor is
supplied with a voltage source. The RMS value of the voltage
source is defined thanks to the parameter named VOLTAGE. It is
the parameter piloted by the macros. The geometry of the test
case is presented in figure 1. The circuit used for the test case is
presented in figure 2.
&ŝŐƵƌĞϰ͗tŽƌŬŝŶŐƉƌŝŶĐŝƉůĞŽĨƚŚĞŵĂĐƌŽ͘
&ŝŐƵƌĞϭ͗'ĞŽŵĞƚƌLJŽĨƚŚĞƚĞƐƚĐĂƐĞ
The Input of the macro “FindOutSupplyForGivenTemperature.pfm“
is presented in figure 3.
When the macro is run, a first computation is done with the initial
value defined by the user in the interface of the macro. At the
end of the computation, we compute the temperature of the last
step of the defined scenario. If the temperature is not in the range
defined by the precision, the macro will restart the computation
with a new value for the supply. The macro will iterate until it
finds out the supply that allows reaching a specific temperature.
Once the value of the supply is found out, an inspection is added
to check if the obtained value is not higher than the maximum
value of the source. The working principle of the macro is provided
in figure 4.
At the end of the computation, when the supply value is found out,
the curve of the temperature versus time is created. A text file is
also created in the working directory. For each iteration done, this
text file contains the target temperature, the temperature reached
as well as the value of the voltage for the iteration.
The macro has been applied in the test case presented in the
first part, with the setting presented in figure 3. The value of the
voltage source needed to reach a temperature of 600°C in 50
seconds is 9.5 VRMS and 30.37 ARMS of current. With this supply,
the temperature reached is 599.88°C.
&ŝŐƵƌĞϮ͗ŝƌĐƵŝƚŽĨƚŚĞƚĞƐƚĐĂƐĞ
&ŝŐ
ƌĞ Ϯ ŝƌĐ ŝƚ ŽĨ ƚŚ
Find the supply that gives a target
temperature
The goal of this macro is to search the value of the supply source (it
can be current or voltage source) to obtain a desired temperature
at the end of a predefined scenario. The inputs of the macro are:
• The scenario to solve
• The target temperature
• The sensor allowing to compute the temperature
• The I/O parameter to be varied (VOLTAGE in this example)
• The maximal value of the input parameter
• Precision expected on the temperature
• The maximum number of iterations allowed to find the value
of the supply that gives the target temperature.
&ŝŐƵƌĞϱ͗dĞŵƉĞƌĂƚƵƌĞǀĞƌƐƵƐƟŵĞ͘
&ŝŐƵƌĞϲ͗/ƚĞƌĂƟŽŶƐĚŽŶĞƚŽƌĞĂĐŚƚŚĞƚĂƌŐĞƚĞĚ
ƚĞŵƉĞƌĂƚƵƌĞ͘
(see continued on page 19)
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CEDRAT News - N° 66 - June 2014
Figure 5 represents the curve of the temperature versus time
obtained and figure 6 represents the text file containing all the
iterations done by the macro.
Control supply to match a given result
The goal of this second macro is to control step by step the value
of the supply (RMS value of voltage or current source) to have a
temperature matching a given result. This macro allows predicting
the supply in order to obtain a given profile of temperature. The
inputs of the macro “ControlSupplyToMatchAGivenResults.pfm “are:
• The parameter to pilot
• The variation parameter defining the output (I/O Parameter or
sensor)
• A tabulated parameter describing the desired profile of
temperature
• The value of the time step
• The end time of the scenario
• The precision to reach on the temperature
• The name of the scenario to create
• The maximum number of iterations to find the value of the
supply for each time step
The figure 7 represents the input of the macro:
The working principle used for each time step to find the RMS
value of the supply that gives the target temperature which is
identical to the method used in the previous macro (see figure
4). This method is repeated for each time step.
At the end of the macro run, the scenario defined by the user
is solved; the temperature and the value of the supply can be
displayed thanks to the 2D curve. During the running of the macro,
a text file is automatically created for each time step to store the
iteration used to find the supply that gives the target temperature.
The macro has been applied in the test case presented in the
first part, with the setting presented in figure 7 and with the
temperature profile of the figure 8.
The temperature versus time obtained thanks to the macro is
presented in figure 10. We notice the target temperature and the
obtained temperature are superimposed. The RMS value of the
voltage applied to obtain the desired temperature is presented
in figure 11.
&ŝŐƵƌĞϭϬ͗dĂƌŐĞƚĞĚƚĞŵƉĞƌĂƚƵƌĞΘƚĞŵƉĞƌĂƚƵƌĞŽďƚĂŝŶĞĚ
;ĐƵƌǀĞƐĂƌĞƐƵƉĞƌŝŵƉŽƐĞĚͿ͘
&ŝŐƵƌĞϳ͗/ŶƉƵƚŽĨƚŚĞŵĂĐƌŽ͘
Before running the macro, the user has to define the profile of
expected temperature. It should be done thanks to a tabulated
I/O parameter. An example of tabulated parameter used to define
the temperature profile is presented in figure 8. The curve versus
time of the tabulated parameter is presented in figure 9.
&ŝŐƵƌĞϭϭ͗ZD^ǀĂůƵĞŽĨƚŚĞǀŽůƚĂŐĞǀĞƌƐƵƐƟŵĞ͘
Conclusion
&ŝŐƵƌĞϴ͗WƌŽĮůĞŽĨƚĞŵƉĞƌĂƚƵƌĞͲdĂďƵůĂƚĞĚ͘
Macro is a great asset of Flux 2D/3D. Macros are generally used to
automate repetitive tasks or to build geometry with predefined
input. But as shown in this article, macro allows to develop more
complex functionalities with Flux. Thanks to the macro presented
in this article we are able to pilot a scenario step by step and to
iterate smartly on the value of the supply to obtain targeted results.
In this case, macros replace manual iteration to find the correct
value of the supply according to the temperature expected.
Flux is delivered with a list of ready-defined macros. The full list of
macros is available in the “C:\Cedrat\Extensions\Macros” directory,
with the “macros_list_EN.pdf” file. You will find more macros on
the CEDRAT gate (https://gate.cedrat.com).
&ŝŐƵƌĞϵ͗WƌŽĮůĞŽĨƚĞŵƉĞƌĂƚƵƌĞͲ'ƌĂƉŚ͘
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