Quote:
Originally posted by gone_fishin
Yes, but my main question is the cup limiting the size that the stagnation region will spread out to. Maximising the area each of your jets has to work with inside the individual cups is what I had in mind. Which brings me back to my little sketch that suprisingly nobody has commented on. A cup alone, with ever increasing velocity, seems it would have diminishing returns because of the exit flow interfering ever more powerfully with the incoming jet, no? In other words I would not expect the benefits of increased flow to be linear, but perhaps the curve could be improved upon?
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True, the cup will limit the size of the stagnation region, but this would only be important if there was only a single jet, which there isn't. There is no need to maximise the size of the impingement region for higher flows because even though the region is bound by the cup walls, there's a half-dozen other cups immediately surrounding it, each on benefitting from higher thermal convection as a result of the higher flows.
So better to think of it in terms of the whole, rather than the single jet.
Also, remember that thermal convection drops off fairly quickly outside of the main impingement region, even if the flow rate is increased, so by bounding each region and surrounding it with other regions, we actually get a more uniform heat dissipation spread.
This way, the size of the cups can be tuned to work well with lower flow rates, and still enjoy good performance improvements as the flow rate is increased.