Beyond the Benchmark More Than Just “What the Other Guys Are Doing”
The other guys nh cfd_aa
33
TM HIGH POWER BGA PROCESSOR THERMAL modeling with N.h. cfd tools A few Sample Cases D. Blanchet 04/14/2005
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Transcript of The other guys nh cfd_aa
TM
HIGH POWER BGA PROCESSORTHERMAL modeling
with N.h. cfd tools
A few Sample Cases
D. Blanchet 04/14/2005
TMTHERMAL modeling NEW TOOL EVALUATIONAir coolingConduction cooling Heat pipes TE coolers TransientLiquid Flow through cold platesNatural ConvectionDetailed Package study
TMHEAT PIPE STUDYHigh temperature primary heat path
Heat pipes ON
Heat sink
+ 55C
CAB
Cold plate
TMLow temperature primary heat paths
CAB
Heat pipes OFF (frozen)
- 40C wall
standoffs
Cold plate
startup heater
TMresults hot ambient
Heat pipes operating
Sink attached to chassis wall
TMresults hot ambient
TMresults cold ambient -40C
frozen
TMresults cold ambient -40C
frozen
TM
Typical Transient Heating curves heater power only warm up time
•9
Cell @ 0C ~ 820 sec
Total heater power = 250W
Ambient - 40C
TM
Conductioncooled
8 modules
6U CC6 modules
Heat Rejection Unitsection
(optional)Not
ConsideredIn this study
3 Cold plates(series)
inlet
outlet
TM
Chassis walls - 3 cold plates in series – 2.2 KW
800 w
800 w300 w
300 win
out
8 – CCModules @~200W each
6 – CC 6UModules @~100W each
20Cwater
@1 gpm
TM
Coolant temperature rise ~ 7C @ 1 gpm
TM
Component Model parameters
TM6U module Model
Air flow Copper heat sinks
TMModel top view
TMModel mesh – 340,000 cells
TMResults –
Typical temperature profile cross section
Air velocity vectors
TMResults -
Air velocity vectorsThrough heat sinks
TMResults – temperature contours section through heat sink bases
TM
junction temperature predictions @ sea level
AIRFLOW >> 12 CFM 15 CFM 18 CFM 25 CFMPower per processor 0.8” pitch 0.8” pitch 0.8” pitch
35W – 178W total Inlet Tj / outlet Tj Inlet Tj / outlet Tj Inlet Tj / outlet Tj
Inlet air 20C 60 / 80 56 / 74 53 / 69Inlet air 40C 80 / 100 76 / 94 73 / 89Inlet air 55C 95 / 115 91 / 109 88 / 104Power per processor 1.0” pitch 1.0” pitch 1.0” pitch 1.0” pitch
35W – 178W total Inlet Tj / outlet Tj Inlet Tj / outlet Tj Inlet Tj / outlet Tj Inlet Tj / outlet Tj
Inlet air 20C 58 / 73 54 / 66 51 / 61 47 / 54Inlet air 40C 78 / 93 74 / 86 71 / 81 67 / 74Inlet air 55C 93 / 108 89 / 101 86 / 96 82 / 89
TM
Liquid Cooled Module Studies
TM
Serpentine Liquid Flow Path & Temperature Contours
Commercial Processor Design ~260 Watts Total
Laminar flow Nr ~ = 1100 (viscous fluid)
35C0.25 gpm
90CAt spec limit
100 W
TMParallel channel cold plate 6U
6 CPUs @ 90W ea540 Watts one side
35C Water @ 0.33 gpm
Straightmanifolds
MilledParallel
channels
TMLocal mesh control – parallel channels
5 cells per channelCoarser grid
In metal frame
390,000 grid cells
TMCold plate
Full 2 Resistor < j-b / j-c > component models(detailed models available)
TMParallel flow results
Backview
TMResults - Tj
Tj = 58.2C
TMDetailed model
TMDetailed CPU BGA model
TMDetailed model
1,360,000 grid cells
TMDetailed model bga
1,360,000 grid cells
TMDetailed model – wind tunnel
TMDetailed model
pwb
Heat sink
BGA
Air flow
