Impact of the cold regenerator meshes geometry on low
temperature Pulse Tube performancesD. Dherbécourta, S. Martina, I. Charlesa, J-M Duvala, J. Andréb, C. Danielb
aCEA-Grenoble / UGA / IRIG / Département des Systèmes Basses Températures, 17, rue des Martyrs, F-38054 Grenoble, France
bCNES Toulouse, F-31055 Cedex 4, France
ATHENA
Parasitic heat
losses
Half cold
regenerator
Full cold
regenerator
Thickness 0.88 157 mW ± 10 mW 151 mW ± 10 mW
Thickness 0.82 152 mW ± 10 mW 170 mW ± 10 mW
0
10
20
30
40
50
0 10 20P.Δ
P
(bar²
)
Q (Nm3/h)
Half regenerator 0.88Half regenerator 0.82Full regenerator 0.88Full regenerator 0.82
CONTEXT – Pulse Tube coolers in space missions
CONCLUSION
This fundamental project studied the cold regenerator
meshes geometry influence on the PT performances. An
optimal meshes thickness has been highlighted, depending
on the operating conditions (temperature).
When the meshes thickness is optimized, the order of
magnitude of the power gain (50 mW) is not negligible
compared to the operating conditions of the initial 15 K pulse
tube cooler (400 mW).
A combination of this results with regenerator materials
studies would much more improve the basic 15 K pulse tube
cooler performances.
RESULTS - Impact on performances
BREADBOARD - Coaxial heat intercepted PT
ACKNOWLEDGEMENTS
This work is being conducted with a partial support of
CNES. The experimental work at CEA/SBT has been
shared by Camille Choupin, Thibault Romand and Julien
Inigo whose contributions to this project are greatly
appreciated.
Hot regenerator
Cold
regenerator
2 compressors
Input power 100 W
Active phase shift
Cold tip
300K
Fixed temperature
(50, 80 or 120K)
0
40
80
120
160
200
0.8 0.9 1
Cold
pow
er
availa
ble
at
15K
(m
W)
Normalized thickness (-)
Full cold regenerator
Half cold regenerator
Decreasing thickness = more meshes
→ Competition between physical effects
20
22
24
26
28
30
0.8 0.9 1
Cold
tip
tem
pe
ratu
re w
hen h
eate
d a
t 1W
(K
)
Normalized thickness (-)
Full cold regenerator
Half cold regenerator10
11
12
13
14
15
0.8 0.9 1
Low
est
tem
pera
ture
(K
)
Normalized thickness (-)
Full cold regenerator
Half cold regenerator
Optimal thickness of the half cold regenerator depends on the temperature
< 0.8 at low temperatures, around 0.85 at 15 K and about 0.9 up to 25 K
Optimal thickness of the upper part of the cold regenerator always < 0.8
Project: Fundamental work on the PT performances
based on a 15 K PT design
• Less dead volume
• More thermal capacity
• Extended exchange surface
Woven mesh
Scientific space missions use extremely
sensitive detectors (X-Ray, infrared),
requiring power at very low temperature
(< 100 mK)
Precooling at 15 K
with Pulse Tube
coolers
Complex cryogenic chain to obtain such temperatures
Comparison with
reference
Half cold
regenerator
Full cold
regenerator
Thickness 0.88 - 3.2 % - 8.6 %
Thickness 0.82 - 8.2 % - 9.9 %
Study on the geometry of the cold regenerator meshes
(decreasing thickness = increasing meshes number)
GEOMETRY - Cold regenerator
Reference cold
regenerator(Thickness = 1)
Thickness 0.88 0.82
Comparison with
reference
Half cold
regenerator
Full cold
regenerator
Thickness 0.88 + 5.6 % + 15.6 %
Thickness 0.82 + 14.6 % + 18.4 %
• More pressure drop
• Increasing conduction ?
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