Temperature Field Prediction
Based On Finite Difference Method
And Heat Transfer Model
In various industrial scenarios, it is not only necessary to
calculate the temperature at a certain time in the processing
process, but also sometimes in order to be more accurate, it
is necessary to simulate the temperature field (temperature at
any position) of the processed workpiece at any time point.
Finite difference method is an ideal computing tool.
I. World Leading Feat
In 2005, our team completed a feat: under the calculation
conditions at that time, in the web version of the software,
we can use the finite difference method to complete more than
50 processes, such as air cooling, dozens of passes rolling of
wire and bar, water cooling and so on, and calculate the
temperature field at any time point! And the calculation
results are consistent with the measured data! (see the
figure below)
Our team further optimized the finite difference method
software that has been used by a worldclass large company for
many years, such as re modeling with more than ten books and
thousands of pages of test results sorted out all over the
world for decades to determine the accurate heat transfer
coefficient model; Then use the calculation model of relevant
temperature in hundreds of models developed by our team!
In the operation of the finite difference method, in order to
make the web version software run in a short time, the
operation process has to be greatly improved, which also
restricts the accuracy of the operation. If you refine the
mesh and increase the operation time, the operation accuracy
can be greatly improved! In the comparison with the field
measurement data, since only the surface temperature can be
measured, only the surface temperature can be compared!
In the competition with
European and American counterparts in the past few decades,
the project leader has always taken the lead with the high
precision of the model!
Although the finite element method (the doctoral project field
of the project leader) can also simulate the temperature, it
is too large a calculation system, and it still needs several
hours of calculation time at that time!
II. Simulation Method
Based on the finite difference method, the temperature models
that have been used in the field for many years, such as the
air cooling temperature before and after each rolling pass,
the temperature of each rolling pass, the water cooling
temperature and the model calculated by steelmo, are further
optimized.
In this example, special consideration should be given to the
heat transfer between hightemperature steel (12001000 ℃) and
water during water cooling, and the heat transfer between
hightemperature steel and steel roll with pass during dozens
of passes; Relatively speaking, the heat transfer with air is
relatively easy!
This model requires several
stages of parameter input:
（1）Phase of cooling in air
（2）In the rolling process, the data of
nearly 30 passes (pass parameters and reduction parameters,
etc.) need to be input one by one
（3）Water cooling parameters, such as water temperature,
whether there is stirring and relative speed (it belongs to
highspeed rolling, and the final rolling speed can be as high
as 100M / S!) etc.
The input parameters mainly include:
steel grade, initial size, initial temperature, final rolling
size, various thermal and mechanical properties, etc.
For properties that vary with
temperature, such as flow stress, Young's modulus, Poisson's
ratio, specific heat, density, thermal conductivity, etc.,
accurate change trends are input.
The project leader personally measured the young's modulus of
a steel at high temperature in his early years, and the
measurement results varied exponentially in different
temperature ranges; Since then, thousands of materials have
been collected in major libraries around the world, and the
above hightemperature properties change with temperature.
Relevant data can be found in the material high temperature
performance section of this website.
III. Technical Application
Examples
The project leader learned about the American steelmo
production line when he was in a domestic university; Since
then, as a senior engineer of this company in the United
States, he led the model development, so he has a lot of
firsthand information on relevant technology development.
In the final stage of production, hightemperature wire rod is
coiled in aircooled environment; Through special temperature
and processing technology, the state with the best mechanical
properties is formed. This is the main process of steelmo.
In steelmo process, the core temperature of the wire rod after
rolling is high, the surface temperature is relatively low,
and the temperature change continues. In fact, the measured
surface temperature is not the same as the wire rod
temperature, which should be grasped through the simulation of
temperature field. Moreover, the temperature field near
steelmo roll is also changing continuously, and the obtained
relevant temperature needs to be effectively simulated and
accurately determined. The change of temperature directly
affects the change of microstructure, and then affects the
mechanical properties.
Figure 1: temperature field prediction
results based on finite difference method and heat transfer
model
Project Cases
Summary,
Key Projs,
Model Projs,
Rolling Mills
Model
System,
Intelli Equip.,
New Level 2,
LiBatt
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