New Plate Baffle Water Flow. Quick Simulation Use triangular prism as rough estimate of a vane...
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![Page 1: New Plate Baffle Water Flow. Quick Simulation Use triangular prism as rough estimate of a vane Uniform heat flux on each surface –600 kWm -2 on end face.](https://reader035.fdocuments.in/reader035/viewer/2022070307/551ae4d95503466b6a8b5db3/html5/thumbnails/1.jpg)
New Plate Baffle Water Flow
![Page 2: New Plate Baffle Water Flow. Quick Simulation Use triangular prism as rough estimate of a vane Uniform heat flux on each surface –600 kWm -2 on end face.](https://reader035.fdocuments.in/reader035/viewer/2022070307/551ae4d95503466b6a8b5db3/html5/thumbnails/2.jpg)
Quick Simulation• Use triangular prism as rough estimate of a vane
• Uniform heat flux on each surface– 600 kWm-2 on end face (highest flux at cutback…
average would be much less!)– 20 kWm-2 on side faces– Symmetry at other end, stagnant air convection on top
surface
• See what temperature copper gets to
• (Next, use better vane shape and heat flux)
![Page 3: New Plate Baffle Water Flow. Quick Simulation Use triangular prism as rough estimate of a vane Uniform heat flux on each surface –600 kWm -2 on end face.](https://reader035.fdocuments.in/reader035/viewer/2022070307/551ae4d95503466b6a8b5db3/html5/thumbnails/3.jpg)
Flow Estimates
pcm
PT
2504.1
7513.1
1419.5H
av
D
vLp
H
u
D
kNHTC
Total power, P, to be removed from 355mm long prism ≈ 2 kW
Water mass flow rate, , per pipe = 0.157 kgs-1 (assuming flow speed = 2 ms-1 = 9.42 L min-1)
Estimated temperature rise, ΔT, of cooling water ≈ 3 °CPipe length, L, within copper = 2.1 mAverage water flow rate vav = 2 ms-1
Pipe diameter, DH = 10 mmEstimated pressure drop, Δp = 0.12 Bar
m
Nusselt number, Nu, of water flow = 144.2Thermal conductivity of water, k = 0.6 Wm-1K-1
Estimated heat transfer coefficient = 8650 Wm-2K-1
![Page 4: New Plate Baffle Water Flow. Quick Simulation Use triangular prism as rough estimate of a vane Uniform heat flux on each surface –600 kWm -2 on end face.](https://reader035.fdocuments.in/reader035/viewer/2022070307/551ae4d95503466b6a8b5db3/html5/thumbnails/4.jpg)
Very crude approximation of vane shape and input heat flux, but overall temperature distribution is comparable to previous, more accurate simulations (small image above)
![Page 5: New Plate Baffle Water Flow. Quick Simulation Use triangular prism as rough estimate of a vane Uniform heat flux on each surface –600 kWm -2 on end face.](https://reader035.fdocuments.in/reader035/viewer/2022070307/551ae4d95503466b6a8b5db3/html5/thumbnails/5.jpg)
Average Outlet Water Temperature = 18 °C
Inlet Water Temperature = 15 °C
Racetrack path of water flow repeatedly redistributes heat from primary heat input region on left to cooler region on right.
Water absorbs a lot of heat
Water becomes cooler again
![Page 6: New Plate Baffle Water Flow. Quick Simulation Use triangular prism as rough estimate of a vane Uniform heat flux on each surface –600 kWm -2 on end face.](https://reader035.fdocuments.in/reader035/viewer/2022070307/551ae4d95503466b6a8b5db3/html5/thumbnails/6.jpg)
Average HTC = 9000 Wm-2K-1
Higher HTCs on thinner channels where water flow is faster
![Page 7: New Plate Baffle Water Flow. Quick Simulation Use triangular prism as rough estimate of a vane Uniform heat flux on each surface –600 kWm -2 on end face.](https://reader035.fdocuments.in/reader035/viewer/2022070307/551ae4d95503466b6a8b5db3/html5/thumbnails/7.jpg)
Sharp transitions between layers increase the water pressure significantly compared to estimate for smooth cooling channel
![Page 8: New Plate Baffle Water Flow. Quick Simulation Use triangular prism as rough estimate of a vane Uniform heat flux on each surface –600 kWm -2 on end face.](https://reader035.fdocuments.in/reader035/viewer/2022070307/551ae4d95503466b6a8b5db3/html5/thumbnails/8.jpg)
Comparison of ResultsProperty Hand estimate ANSYS CFD Result
Mass flow rate 0.157 kgs-1 (9.42 Lmin-1)
0.1545 kgs-1 (9.27 Lmin-1)
Average water flow 2 ms-1 1.914 ms-1
Maximum water flow 5 ms-1 (desired upper limit)
4.227 ms-1
Total Pressure 0.12 Bar 0.375 Bar
Average HTC 8650 Wm-2K-1 9000 Wm-2K-1
Water temperature rise
3 °C 3 °C
Simulation matches back-of-the-envelope calculations (again… well done ANSYS!)
Copper temperature similar to previous simulations with different flow Good
To do now: try a more accurate model and put in a squirt nozzle