simple cfd estimate of end flange tuner finger cooling
DESCRIPTION
Simple CFD Estimate of End Flange Tuner Finger Cooling. Estimated Dimensions. 6mm. 5cm. 1cm. 1cm. 3cm. 2cm. 4cm. 5cm. Estimated Heat Load. IPHI RFQ end flange: 26 Wcm -2 on fingers - PowerPoint PPT PresentationTRANSCRIPT
Simple CFD Estimate of End Flange Tuner Finger Cooling
Estimated Dimensions
2cm
1cm
1cm3cm
5cm
6mm
4cm
5cm
Estimated Heat Load
FETS RFQ: 62 Wcm-2 at vane cut-back
Assume less than half this on fingers? So 25 Wcm-2 is reasonable.
IPHI RFQ end flange: 26 Wcm-2 on fingers
(CW RFQ, though, so ours will have much less than this in reality, but 25 Wcm-2 will allow large safety margin)
15°C Water in at 1 ms-1 flow rate
Water out with temperature raised and at 0 Bar relative pressure
25 Wcm-2 heat flux load on finger
High mesh density in region between finger and pipe
Copper starting temperature = 22°C
Flow Estimates
pcm
PT
2504.1
7513.1
1419.5H
av
D
vLp
H
u
D
kNHTC
Total power, P, to be removed from each finger ≈ 160 W
Water mass flow rate, , per pipe = 0.028 kgs-1 (assuming flow speed = 1 ms-1 = 1.7 l min-1)
Estimated temperature rise, ΔT, of cooling water = 1.35 °C
Pipe length, L, within copper = 10 cmAverage water flow rate vav = 1 ms-1
Pipe diameter, DH = 6 mmEstimated pressure drop, Δp = 0.003 Bar
m
Nusselt number, Nu, of water flow = 55.03Thermal conductivity of water, k = 0.6 Wm-1K-1
Estimated heat transfer coefficient = 5500 Wm-2K-1
Intersection of drilled pipes slightly disrupts smooth flow
Faster, disrupted flow round corner increases local HTC
Average HTC ~ 6000 Wm-2K-1 which agrees with estimate
Temperature rise of water ~ 2 °C which agrees with estimate
Pressure drop is slightly higher than estimate because the pipe doesn’t have a smooth bend at corner, but it’s still nice and low
Bulk copper in end flange is ~ 40 °C
Finger gets pretty warm (100 °C) but that shouldn’t matter at all
Summary
• Majority of heat removed ok• Indirect cooling means finger gets hot• …but not enough to worry about• Assumes 25 Wcm-2 heat load
(OVERESTIMATE!)• Will proceed with RF simulation to get better
estimate of heat load on fingers• Overall, this cooling strategy should be fine