Transcript ppt

Power cooling changes to EE
Initial scheme
Main manifold serving 5 columns
Each column with 2 cooling blocks
Flow and return manifolds each served by 2 12/14
pipes at 0.2l/s (12l/m) per pipe
Sagana compression fittings
New scheme
Main manifold split into 2 separate sections
A super unit with 3 columns
A super unit with 2 columns
Cooling blocks welded together via pipes/Tees
to form a single item – a column
Columns welded to manifold
Full super unit is He and pressure tested before
mounting on Dee
D Cockerill RAL EE cooling review 13.9.2007
Power cooling changes to EE
Benefits/risks of new scheme
Pre-assembled and tested units
Only 2 Sagana fittings to outside per super unit
Only one pressure/leak test on Dee per super unit
Can dismount single super units after Dee assembly
Rely on welded joints – QC issues – x-ray all joints
Alignment of pipes/Tees critical
Benefits/risks of old scheme
Standard off the shelf components
Mature design, successfully trialed on Dee4
Many Sagana fittings to tighten in confined spaces
Requires many pressure/leak tests on Dee. Helium not allowed.
If one block bad, have to dismount all other blocks from
extremity of quadrant to get at faulty item
Notes Mtgs Thur Aug 9 Werner, Tiziano, Dieter, John, Justin, DJAC
Mon Aug 6 Justin, John, Justin, Ken, DJAC
D Cockerill RAL EE cooling review 13.9.2007
Power cooling changes to EE
A column of 2 welded cooling blocks
Pressure and He leak tests OK
D Cockerill RAL EE cooling review 13.9.2007
Power cooling changes to EE
Welded pipe
connections to
columns (flow)
Flexible pipe
connections
to columns
(return)
Main manifolds to columns
Use mechatronics support plate as jig for welding columns to main manifold
Column positioning defined by welding the solid flow pipes to manifold
Remove over constraints by welding return pipes to manifolds with flexibles
D Cockerill RAL EE cooling review 13.9.2007
Power cooling changes to EE
One Sagana
fitting for
the return
of the 3
column unit
One Sagana
fitting for the
flow of the 3
column unit
View of the complex pipe runs to the outside of the patch panel
D Cockerill RAL EE cooling review 13.9.2007
Power cooling changes to EE
View of the complex pipe runs to the outside of the patch panel
D Cockerill RAL EE cooling review 13.9.2007
Power cooling changes to EE
Flow in blocks/bars
Old scheme
Main manifold 2 x 0.2l/s
Each block
Each bar
= 0.4 l/s
= 0.04 l/s
= 0.013 l/s
(for 5x2 = 10 blocks)
New Scheme
3 column unit, main manifold 0.2 l/s
Each block
= 0.033 l/s
Each bar
= 0.011 l/s
2 column unit, main manifold 0.2 l/s
Each block
= 0.05 l/s
Each bar
= 0.017 l/s
The 3 column blocks will have 17% less flow than in the old scheme
Test electronics cooling as a function of flow rate at H4 after beam tests.
D Cockerill RAL EE cooling review 13.9.2007
Power cooling changes to EE
1
2
3
4
Super unit regions – mirror symmetry across quadrants
Each super unit will be held in its own jig in order to offer it
up to the Dee, using a variable height trolley, the Dalmec for
SM assembly, or by crane – but NOT by hand!
D Cockerill RAL EE cooling review 13.9.2007
Flow considerations
Reynolds number
In fluid mechanics, the Reynolds number is the ratio of inertial forces (vsρ) to viscous forces (μ/L) and consequently it quantifies
the relative importance of these two types of forces for given flow conditions. Thus, it is used to identify different flow regimes,
such as laminar or turbulent flow.
It is one of the most important dimensionless numbers in fluid dynamics and is used, usually along with other dimensionless
numbers, to provide a criterion for determining dynamic similitude. When two geometrically similar flow patterns, in perhaps
different fluids with possibly different flowrates, have the same values for the relevant dimensionless numbers, they are said to be
dynamically similar.
It is named after Osborne Reynolds (1842–1912), who proposed it in 1883.[1]
Typically it is given as follows:
Re = Vs . L /

where:
vs - mean fluid velocity, [m s-1]
L - characteristic length, [m][2]
μ - (absolute) dynamic fluid viscosity, [N s m-2] or [Pa s]
ν - kinematic fluid viscosity: ν = μ / ρ, [m2 s-1]
ρ - fluid density, [kg m-3].
For flow in a pipe for instance, the characteristic length is the pipe diameter, if the cross section is circular, or the hydraulic
diameter, for a non-circular cross section.
Laminar flow occurs at low Reynolds numbers, where viscous forces are dominant, and is characterized by smooth, constant fluid
motion, while turbulent flow, on the other hand, occurs at high Reynolds numbers and is dominated by inertial forces, producing
random eddies, vortices and other flow fluctuations.
The transition between laminar and turbulent flow is often indicated by a critical Reynolds number (Recrit), which depends on the
exact flow configuration and must be determined experimentally. Within a certain range around this point there is a region of
gradual transition where the flow is neither fully laminar nor fully turbulent, and predictions of fluid behaviour can be difficult. For
example, within circular pipes the critical Reynolds number is generally accepted to be 2300, where the Reynolds number is based
on the pipe diameter and the mean velocity vs within the pipe, but engineers will avoid any pipe configuration that falls within the
range of Reynolds numbers from about 2000 to 3000 to ensure that the flow is either laminar or turbulent.
D Cockerill RAL EE cooling review 13.9.2007
Flow considerations
Reynolds number
Re = Vs . L . ρ / μ = 5120
where:
vs - mean fluid velocity, [m s-1]
L - characteristic length, [m][2]
ρ - fluid density, [kg m-3].
μ - (absolute) dynamic fluid viscosity, [N s m-2] or [Pa s]
Inputs
vs - Fluid velocity (0.011 l/s)
L - for flow in a pipe for instance,
the characteristic length L is the pipe diameter (4mm)
if the cross section is circular
ρ - Fluid density
1.14 m s-1
1000 kg/m3
μ - viscosity of water
8.90 × 10−4 Pa·s
4.10-3 m
Based on this calculation the system is comfortably above the Reynolds number for the
transition to turbulent flow at R = 2300
D Cockerill RAL EE cooling review 13.9.2007
Conclusions
New scheme offers benefit of pre tested modular
units
Initial prototyping has been successful
Next step – completion of a 3 column super unit
D Cockerill RAL EE cooling review 13.9.2007