Download Analysis on Coupled Fields inside Passage by Finite Element Method

Analysis on Coupled Fields inside Passage by Finite Element Method
and Its Applications
WANG Hao , LIU Lily
College of Science, Liaoning Technical University, Fuxin, Liaoning, 123000
[email protected]
Abstract: By analyzing the dynamic flow driven by the electrolyte solution in the magnetic field and
electric field that generated respectively by solenoid and parallel plate electrodes, this article did the
electromagnetic field calculation and flow field calculation via ANSYS software, and the results from
the electromagnetic coupling analysis were obtained thereby.
Key words: ANSYS; Solenoid; Electromagnetic force; Electrolyte solution
0
Introduction
The electrolyte solution inside passage driven by electromagnetic force is a coupled field
composed of electric field, magnetic field and flow field, the electric field will be generated if the
powered plates of both positive and negative polarity are parallelized on both sides of the passage. This
passage is also inside the long straight solenoid and the magnetic field can be generated by electrifying
the solenoid. The electromagnetic interaction will create Lorentz force, which will change the
distribution of the flow field and boost forward the electrolyte solution. According to the finite element
solution process of the flow field and electromagnetic field obtained by analyzing the flow field and
electromagnetic field via finite element method, the coupled field inside the passage can be calculated.
The general steps of calculating the coupled field are showed as Fig. 1.
Begin
Determine the finite element analysis model
Initialize the flow field areas, parameters and variables
Calculate the distribution of the electromagnetic field at t0
Calculate the electromagnetic force upon the electrolyte solution
Put the electromagnetic force into the fluid momentum
equation; calculate the flow field distribution at ti
Y
▏V -V ▏≤δ
ti
N
titi-T
end
Fig.1 Program design flow of calculating the coupled field
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Put Vti into the Maxwell
Equation; calculate the
electromagnetic field
distribution at ti
1
Ansys Analysis Model
The two-dimensional calculation model used in the ANSYS analysis is showed in Fig.2. The
passage is in rectangular shape with an interior magnetic field generated by solenoid or multiphase
alternative superconducting magnet. Two sets of phases with a phase number of 20 are on the upper and
lower sides respectively. Under the effect of magnetic field and actuated by it, the electrolyte solution in
the passage will flow.
Fig.2 Calculation model for ANSYS analysis
Preferences:
(1) Passage of the electrolyte solution: length=1200mm; width=200mm; height=140mm
(2) Solenoid: length=1500mm; diameter=1.5mm; number of windings=1000/2000; conducting
wire: enameled copper wire with a electrical resistivity of 1.7 10-8 m; conducted current: 0-15A.
(3) Set the electric conductivity of the electrolyte solution as a constant number =10.0s/m, with
a density of =1100kg/m3 and a viscosity coefficient of =0.0017Ns/m2.
(4) DC magnetic field follows the positive direction of Y axis, while AC travelling wave magnetic
field follows the positive direction of X axis. The exciting current in the coil is J=100A. The end effect
at inlet and outlet of the passage is neglected
ρ
2
μ
× Ω
σ
Mesh Generation for ANSYS Analysis
For finite element simulation via computation model, the first thing is to generate grid mesh, see
Fig.3. As for plane-type two-dimension simulation analysis, the quadrangular cell is used to divide the
whole model.
Fig.3 Mesh generation for ANSYS analysis
3
Calculation of Electric Field
According to the above model, the electric conductivity of the electrolyte solution can be calculated
as 10.0s/m when DC electric pressure is 30V. The distribution of electric field vectors in electrolyte
solution between the polar plates is showed in Fig.4.
Fig.4 Distribution of electric field vectors in electrolyte solution
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Calculation of Magnetic Field
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The length of the solenoid of the enameled copper wire is 1.5m with a diameter of 0.0015m. The
conducted current is 0.5-30A while the number of windings is 2000. The vector graph of magnetic
induction density generated in electrified solenoid and distribution map of magnetic induction density
are showed in Fig.5 respectively. The map for magnetic intensity vector and magnetic field intensity is
showed in Fig.6. Due to the internal diameter of the solenoid is smaller than its length, the magnetic
field in the solenoid is short of homogeneity, and the edge effect is relatively evident. The magnetic
field distribution follows the solenoid axial line (Z axis) direction can be observed in the below pictures.
Fig. 5 Distribution map of magnetic induction density B generated in electrified solenoid
Fig. 6 Distribution map of magnetic field intensity H generated in electrified solenoid
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Calculation of Electromagnetic Force
The electric field generated between the polar plates and the magnetic field generated in the
solenoid act on the electrolyte solution, driving it by electromagnetic force. The calculation vector
graphs of the electromagnetic force are showed in Fig.7.
Fig.7 Vector analysis for electrolyte solution under electromagnetic force
Due to the differences of electric pressures between the polar plates and the differences of the
current intensity passing the solenoid, different vector graph analyzing results for electromagnetic force
are obtained and showed in Fig.8.
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Fig.8 Analysis on electromagnetic force when change the electric pressure between the polar plates and
electric current in the solenoid.
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Calculation of Flow Field Driving
By coupling the electromagnetic field inside solenoid with the passage of the electrolyte solution,
the actuating speed distribution of the flow field inside passage at a specific time can be calculated.
When the electrified electric current inside coils of the solenoid is 5A, the actuating speed distribution of
the flow field can be observed in fig.9.
Fig.9 vector distribution of the actuating speed of the electrolyte solution flow field inside passage
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Calculation of Flow Field
The resulting actuating speed acts upon the electrolyte solution in the passages that outside
electromagnetic field, and via calculation the liquid flow situation is showed in Fig.10.
Fig.10 Flow field speed distribution of the electrolyte solution inside passage
Putting circular cylinder into the electrolyte solution outside passage, along with the adding of the
actuating speeds the possibly generable circumfluence phenomena on the circular cylinder can be
observed in Fig. 11.
Fig. 11 Circumfluence distribution of the circular cylinder in electrolyte solution of the exterior passage
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Different actuating speeds usually mean different size and distribution of the eddy-making upon
the circular cylinder. While the flow field distribution of the liquid of same electrolyte solution density
at different electric current that generating different actuating speeds can be observed in Fig.12
Fig.12 Circumfluence distribution of the circular cylinder in electrolyte solution at different electric current
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Conclusions
Based on gradually perfected finite element ANSYS calculation method, this article mainly
analyzed the obtained display, image and flow speed field for the conducting fluid driven flow and
image display for Circumfluence of the circular cylinder etc. by combining the equation of electrolyte
solution flow driven by electromagnetic force with discretization process, coupling method, model
building and spacial tridimensional calculation. The analytical results for electric field, magnetic field,
electromagnetic force and coupled field etc. were obtained thereby.
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