Quote:
Originally posted by bigben2k
Did you calculate any improvement in increasing the fin height?
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Yes. A higher fin height works better for lower flow rates. As we lower the fin height, we lower the cross-sectional water area, and this correspondingly boosts water velocity with the caveat of requiring a higher pressure pump to get adequate returns for doing so.
Les had an interesting series of graphs over at OCAU that plotted pump pressure vs water flow vs performance for some different wall/channel thicknesses/heights and the graphs were roughly showing that the differences are minimal. As we boost the pump pressure for a "tighter" block to bring its performance up, the block doesn't perform that much better if the same pump pressure is applied to a block of "more open" proportions.
So it seems that no matter what, it hinges on the pump. We can build a block that needs a high pressure pump to perform, but will it perform better than a freer flowing block when the same pump is attached? I suppose that then becomes a factor of the pump's rated flow rate at various pressures. Basically we need positive displacement pumps to guarantee our flow rates.
At this level we all do tend to get rather muddy on what will work and what won't in practise.
I'm just at the stage of where I can safely say that micro-channels is one way to achieve better than flat-plate/wide-channeled designs which all perform about the same, but predicting what can be done around the micro-channel concept to push it further is still definately experimental.