26-29 Nov. 2003 - Superconducting magnetic levitated bearings for rotary machines
Superconducting magnetic levitated bearings
for rotary machines
5th International Symposium on Advanced
Nova University of Lisbon Electromechanical Motion Systems Marrakech
1
A Leão Rodrigues
Layout
Brief description of superconductor materials Calculation of magnetic levitation forces Journal magnetic bearings design Thrust magnetic bearings design Levitation experiment Conclusions
•Discovery of Superconductivity
Heike Kammerling Onnes in his Cryogenic Laboratory at
Leiden University, Holland, 1911
5th International Symposium on Advanced
Nova University of Lisbon Electromechanical Motion Systems Marrakech
2
Hg
0,025
0,00
0,05
0,075
0,10
0,125
0,15
4o00 4o10 4o20 4o30 4o40T (K)
10-5
Onnes results
Resistence
26-29 Nov. 2003 - Superconducting magnetic levitated bearings for rotary machines
Aiu
TV
Mercury
Thermometer
Liquid Helium
Onnes Experiment
• Magnetic Field Effect
Superconductor State
Normal State
0 Tc T
Hc
H(T) Magnetic Field
2
1c
c T
THTH
12
24
36
0 2 4 6 8
Hc
(kA
/m)
Leather (Pb)
Mercury (Hg)
Selenium(Sn)Indium(In)
Thallium (Tl)
T(K)
Low Temperature Superconductors (LTS), or 1st generation discovered until 1970.
5th International Symposium on Advanced
Nova University of Lisbon Electromechanical Motion Systems Marrakech
3
26-29 Nov. 2003 - Superconducting magnetic levitated bearings for rotary machines
Onnes Experiment
Aiu
TV
Material
Thermometer
Liquid Helium
H
26-29 Nov. 2003 - Superconducting magnetic levitated bearings for rotary machines
Jc
Tc
Hc
Current density, J
Magnetic field, H
Temperature, T
0
Superconductivity region
Critical Surface
Region of normal state
• The superconductivity state of a material is destroyed if one of the following parameters are out of the critical surface:
• Critical superconductivity (TC)
• Critical magnetic field (HC)
• Critical current density (JC)
Lost of Superconductivity
SuperconductorI S
SI
J
Tc T
Superconductor state
Normal state
0
Jc
J(T) Current density
2
1c
c T
TJTJ
5th International Symposium on Advanced
Nova University of Lisbon Electromechanical Motion Systems Marrakech
4
26-29 Nov. 2003 - Superconducting magnetic levitated bearings for rotary machines
• Meissner Effect
5th International Symposium on Advanced
Nova University of Lisbon Electromechanical Motion Systems Marrakech
5
Ferromagnetic
Magnet
R
Lpicoseconds
oI
Metal
t0
t
oeIti
t
oeIti
H
M
A superconductor is a diamagnetic material Negative magnetic susceptibility
Supercondutor
Magnet
R
L
• In 1933, Walter Meissner and Robert Ochsenfeld observed that the magnetic flux was expelled from the interior of the superconductor.
Supercondutor
Persistent current oI
Walter Meissner
26-29 Nov. 2003 - Superconducting magnetic levitated bearings for rotary machines
5th International Symposium on Advanced
Nova University of Lisbon Electromechanical Motion Systems Marrakech
6
Bardeen Cooper Schiffer
• BCS Theory• . In 1957 the scientists John Bardeen, Leon Cooper e John Schiffer, from Illinois University, presented a mathematical model that described the superconductivity phenomenon in the low temperature superconductors, called BCS theory.
F F
Cooper pair
Electron 1 Electron 2T < Tc
. Two free electrons when cooled down at temperature T<Tc are attracted forming a Cooper pair. Then, the pair travels through the crystalline structure without touching it and therefore finding no resistance.
5th International Symposium on Advanced
Nova University of Lisbon Electromechanical Motion Systems Marrakech
7
H
Supercondutor
increasing
- M
HHc0Type I superconductor
H
M
Type I superconductors attain abruptly the normal state for a given critical magnetic field Hc
- M
HHc10 Hc2
increasing
Vortexes
H
Type II superconductor
Type II superconductors start attaining transition for a given critical magnetic field Hc1. Vortexes are
formed and for Hc2> Hc1
the superconductivity is totally lost.
26-29 Nov. 2003 - Superconducting magnetic levitated bearings for rotary machines
Bednorz e Alex Muller, in IBM laboratories, near Zurique, in 1986.
Crystalline structure of La2CuO4
Transition curves of La2CuO4
Tc = 20 K
•High Temperature Superconductors (HTS)
5th International Symposium on Advanced
Nova University of Lisbon Electromechanical Motion Systems Marrakech
8
• In 1986, George Bednorz e Alex Müller, from IBM laboratories in Rüschliko (Switzerland), discovered a ceramic composite based in lanthanum, which was superconductor around the transition temperature of 20 K.
26-29 Nov. 2003 - Superconducting magnetic levitated bearings for rotary machines
•YBCO Superconductor (Yttrium, barium and copper oxide)
YBCO ceramic blocks
YBCO ceramic ringsYBCO ceramic disc
Paul Chu discovered YBCO in 1987 at the University of Huston.
Tc = 86 K
5th International Symposium on Advanced
Nova University of Lisbon Electromechanical Motion Systems Marrakech
2
YBa2Cu3O7
Crystalline structure of YBCO
O
O
O
Ba
Ba
Y
Cu
Cu
26-29 Nov. 2003 - Superconducting magnetic levitated bearings for rotary machines
• Superconductors evolution versus time
5th International Symposium on Advanced
Nova University of Lisbon Electromechanical Motion Systems Marrakech
10
Liquid nitrogen 77 K
26-29 Nov. 2003 - Superconducting magnetic levitated bearings for rotary machines
5th International Symposium on Advanced
Nova University of Lisbon Electromechanical Motion Systems Marrakech
11
Superconducting Levitation Force
Superconductor
NdFeB Permanent Magnet
Superconductor
26-29 Nov. 2003 - Superconducting magnetic levitated bearings for rotary machines
Superconductor materials applications
Evolution of the superconductors materials application
Source: ISIS – International Superconductivity Industry Summit.
1995 2000 2010 2020
Electronics
Energy - bearings
Transportation
Industry
Instrumentation
5th International Symposium on Advanced
Nova University of Lisbon Electromechanical Motion Systems Marrakech
12
Year
26-29 Nov. 2003 - Superconducting magnetic levitated bearings for rotary machines
LEVITATION FORCE CALCULATION
x
z(mm)0 2 4 6 8 100.1
1
10
100
HTS
REM z
YBCOBSCCO
Levitation force (mN)
Computed Experimental
t
Measured levitation force between a HTS and a REM versus vertical distance z
5th International Symposium on Advanced
Nova University of Lisbon Electromechanical Motion Systems Marrakech
13
HTS material BmagnetJinduced
Permanent magnet
z
y
z
t
Levitation force
F
Liquid nitrogen
t (mm)0 5 10 15 20 25 0.1
5
10
BSCCO
Levitation force (mN)
15
20
HTS t
YBCO
REM
Thickness of bulk YBCO dependence on levitation force
z = 5 mm
n
i
n
i
r
mean
V
V
1
1
x
z
y
x
zyzxz
zyyxy
zxyxxor
z
y
x
dS
dS
dS
BBBBBB
BBB
BBB
BBBBB
B
df
df
df
2
2
21
22
22
22
Maxwell stress method
26-29 Nov. 2003 - Superconducting magnetic levitated bearings for rotary machines
5th International Symposium on Advanced
Nova University of Lisbon Electromechanical Motion Systems Marrakech
14
26-29 Nov. 2003 - Superconducting magnetic levitated bearings for rotary machines
Journal magnetic bearing design
5th International Symposium on Advanced
Nova University of Lisbon Electromechanical Motion Systems Marrakech
15
Shaft
HTS cylinder
NdFeB permanent magnet
f = 9.7 N/cm2
Force density distribution surface alongside the magnetic bearing
r
DB
A
F
o
s
24
3 2
Journal magnetic bearing layout
Shaft
Permanent magnet
Superconducting ring
Copper ring
g
Permanent magnet
Superconducting ring
Copper ring
Commercial journal magnetic bearing
26-29 Nov. 2003 - Superconducting magnetic levitated bearings for rotary machines
Thrust magnetic bearing design
a) Lower part (HTS)
b)Upper part (PM)Layout of the thrust magnetic bearing
HTS blocks Stabilization
NdFeB blocksAir gaps
300
Thrust magnetic bearing flux plot
NdFeB NdFeB NdFeB
YBCO YBCO Liquid nitrogen
Levitator Thrust magnetic bearing
5th International Symposium on Advanced
Nova University of Lisbon Electromechanical Motion Systems Marrakech
16
Liquid nitrogen
26-29 Nov. 2003 - Superconducting magnetic levitated bearings for rotary machines
Magnetic Levitation
5th International Symposium on Advanced
Nova University of Lisbon Electromechanical Motion Systems Marrakech
17
26-29 Nov. 2003 - Superconducting magnetic levitated bearings for rotary machines
Conclusions
5th International Symposium on Advanced
Nova University of Lisbon Electromechanical Motion Systems Marrakech
18
Maxwell stress method to evaluate levitation forces between a
permanent magnet and a YBCO superconductor under zero field
cooling was presented.
Results for magnetic pressures are of the order of 10 N/cm2. The method was applied to the design of journal and thrust bearings. These devices are now commercially produced and the market
expectation shows a broad and innovative potential of industrial
application.
26-29 Nov. 2003 - Superconducting magnetic levitated bearings for rotary machines
5th International Symposium on Advanced
Nova University of Lisbon Electromechanical Motion Systems Marrakech
20
Top Related