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600 groove width = 0.6 mm
550 2
T cc '7
boiling heat transfer coefficient [W/m K]
K SE
circular; 4 m/s rectangular; 4 m/s triangular; 4 m/s circular; 1 m/s rectangular; 1 m/s triangular; 1 m/s
500 450 400 350 300 250 200 150 100 0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
1.3
1.4
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)LJXUH ,QVLGH DUHD IRU WKH WKUHH JURRYHV IRUDFRQVWDQWJURRYHZLGWKRIPP
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
60
2
overall heat transfer coefficient [W/m K]
groove with = 0.6 mm 55 50 45 circular; 4 m/s rectangular; 4 m/s triangular; 4 m/s circular; 1 m/s rectangular; 1 m/s triangular; 1 m/s
40 35 30 25 20 0.1
320 0.3
0.5
0.7
0.9
1.1
1.3
300
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280
groove depth [mm]
layer thickness = 0.5 mm heat rate, 4 m/s heat rate, 1 m/s
260 240
heat rate [W]
220 200 180 160 140 120
2
Overall & boiling heat transfer coefficient [W/m K]
320
100
300
80
layer thickness = 0.5 mm
280
60
260
boiling htc, 4 m/s overall htc 4 m/s boiling htc, 1m/s overall; 1 m/s
240 220
40 20 0 0
200
20
30
40
50
pore size [Pm]
180
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160 140 120 100 80 60 40 20 0 0
r
10
r
10
20
30
40
50
pore size [Pm]
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200
2
overall & boiling heat transfer coefficient [W/m K]
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boiling htc, 4 m/s overall htc, 4m/s boiling htc, 1 m/s overall htc, 1 m/s
140 120 100 80 60 40 20
0.25
0.50
0.75
1.00
1.25
1.50
1.75
2.00
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300 280
particle size = 50 Pm (pore size 20 Pm)
heat rate, 4 m/s heat rate, 1 m/s
260 240 220
heat rate [W]
5()(5(1&(6
particle size = 50 Pm (pore size 20 Pm)
160
0 0
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180
200 180 160 140 120 100 80 0
0.25
0.50
0.75
1.00
1.25
1.50
1.75
2.00
layer thickness [mm]
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