Preliminary Failure Modes and Effects Analysis of the US DCLL Test
DCLL ½ port Test Blanket Module thermal-hydraulic analysis
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Transcript of DCLL ½ port Test Blanket Module thermal-hydraulic analysis
DCLL ½ port Test Blanket Module
thermal-hydraulic analysis
Presented by
P. Calderoni
March 3, 2004 UCLA
Input parameters for the ½ port module (Wong, Sawan March 2005):
Surface heat flux q’’ = 0.3 MW/m2 over 90% of FW / 0.5 MW/m2 over 10% of FW
First wall surface = 1.94 m X 0.64 m = 1.25 m2
Power from radiative flux = 0.4 MW
Nuclear heating power = 0.913 MW
Total power handled by the module = 1.313 MW
Power transferred to He cooling (40% of total) = 0.6 MW
Total heat balance
If inlet / outlet He temperature are fixed at 360 C and 440 C the needed cooling mass flux m’ = 1.265 kg/s (Cp = 5192 J/Kg K)
Pressure losses along in/out pipes from HEX to TBM
Why keeping the SiC insert?
A
mv
40 m/s (52 m/s)
Re = 5x105
hD
LfK
vKp
2
2
Friction coefficient (Petukhov corr) = 0.013
8 kPa in coax
(4.5 kPa w/o SiC)
hydraulic diameter:0.086 m
Pipes length L = 80 m x 2 (in / out)
10 m
18 m
18 m
40 m
Pressure losses = 0.11 Mpa (1.375% of inlet pressure)
Side View Back View
90 Y split
8k
30% flow split
2k
turn0.5k
90 turn
2k
90 Y conv 8k
Coaxial piping conv / div in transporter
8k x 2
30% flow split
2k90 turn
2k
turn0.5k
Pressure losses in back-plate distribution circuit
up down
Top, grid plates
FW L to R pass
FW R to L pass
Bottom, grid plates
Pressure losses = 0.04 Mpa
(0.0225 MPa w/o SiC)
0.5 % of inlet pressure (0.28 %)
First Wall
Grid Plate
Vertical He I/O Manifold
Grid Plate He Manifold
Pressure losses in first wall cooling channels
[ DEMO design ]
0.442 kg/s
0.442 kg/s
0.055 kg/s
0.055 kg/s
Initial design configuration:
0.024 m pitch
16 channels per section
0.884 kg/s total mass flow
1.255 m x 5 channel length
v = 16.1 m/s
h = 1375 W/m2 K
dp = 3.6 kPa
20 mm
30 mm
38 mm
For q = 0.3 MW/m2 the heat transfer coefficient needs to be at least 4000 W/m2 K to ensure TFW
max < 550 C
20mm x 20 mm channels:
0.024 m pitch
16 channels per section
v = 24.2 m/s
h = 2000 W/m2 K
dp = 9.4 kPa
10mm x 15 mm channels:
0.014 m pitch
32 channels per section
v = 32.3 m/s
h = 2750 W/m2 K
dp = 29 kPa
10mm x 10 mm channels:
0.014 m pitch
32 channels per section
v = 48.4 m/s
h = 4000 W/m2 K
dp = 75 kPa
Heat transfer could be enhanced by squared ribs perpendicular to the flow on the high heat flux side, as suggested by S. Sharafat (1 x 1 mm ribs with a 6.3 mm pitch) instead of smaller channel dimension.
With similar heat transfer coefficient the ribbed channels configuration generates 64% of the total pressure losses than the smaller smooth channels.
Preliminary results from 2-D simulation of He flow in the FW channels and manifolds by G. Sviatoslavsky show pressure drops that are a factor of 3 higher than those evaluated with Petukhov’s correlation for the channels only.
Estimated total pressure drop in FW = 0.225 MPa (2.8% of inlet pressure)
Cost?Efficiency at high heat flux?Reliability?
Pressure losses in top, bottom and grid plates (design not finalized)
0.38 kg/s (30% of total flow) is diverted to cool all structures other than the FW.
If a channel geometry similar than the FW is assumed a pressure loss of 10 kPa can be used as a first approximation for each cooling plate
Estimated total pressure losses = 0.050 MPa(0.6% of total inlet pressure)
Component Reference pressure drop
Enhanced performance
In / Out pipes 0.11 MPa (1.375%)
Flow distribution 0.04 Mpa (0.5%) 0.0225 (0.28%) 1
FW and manifolds 0.225 Mpa (2.8%) 0.144 MPa (1.8%) 2
Top, bottom and grids 0.05 Mpa (0.6%) 0.0225 (0.28%) 3
Total 0.515 Mpa (6.4%) 0.3 MPa (3.75%)
Summary
1. Eliminate SiC insert from He coaxial pipe (suggested)
2. Use ribs to enhance heat transfer (questionable)
3. Without a finalized design a lower boundary for pressure losses could be found by scaling the FW losses with v2 (use higher value to be conservative)