[Incoherent]

Now we start getting into the real details, limitations to the idea.

Originally Posted by Cathar

I suppose the followup question would naturally be this:

Can you sustain an effective h of 100K (very very difficult I might add) across a spherical surface of high surface area as opposed to a flat surface of smaller area?

I would agree, to the point where I'd say it is difficult to get this number up above 50000 for the sphere. I do have a few little tricks which are not visible in the pictures though. Anyway, in my simple model there is little benefit in trying to go higher, the sphere has very little headroom above about 115000, if you could generate an h of 1000000, it would have very little impact. The Cascade type on the other hand benefits immensely from an increasing convection coefficient.
I see it beating the sphere above 110-120,000 in the simplistic model. Quite within the Cascades reach.
The difference is, the sphere can outperform the thin base anywhere below this, at possibly less than half h.

Originally Posted by Cathar

As a followup consideration, flat plate blocks (Cascade included) typically engage, though surface/wall structure, two to three times the convectional surface area than a pure flat-plate model. Let's assume that the spherical model is doing the same with its available surface, how does that change the outcome once the 1-D conductional costs are factored in?

Another good point. By simply putting in an A multiplier for the Cu-H2O interface area into the model I see the C/W vs 'h' crossover point move. In the flatplate's favour. x2 makes the crossover point ~60000, x3 gives ~40000. The sphere does not benefit from a surface area increase much either.

Originally Posted by Cathar

One further consideration - the thin-base flat-plate model's heat-spread pattern really isn't affected so much with changes in the size/area of the heat-die. With a thick-base spherical model, what happens as the die size approaches the size of the hemisphere and spreading resistance becomes a factor again?.

I am not sure. Perhaps the ideal shape would become less spherical, heading towards a flat plate. In this scenario your first point (hard to maintain high 'h' over large area) starts applying to all blocks.
Edit: with a gaussian power distribution over the die I think the sphere remains valid.

Originally Posted by Cathar

Am just musing over the implications of the physical implementation, rather than the simplistic theory of it. Not intending to be negative at all - just to promote further thought.

I welcome it. It is good to probe the disadvantages, I started this thread hysterically excited that something I had come up with seems to actually work in a manner in line with the theory that generated it. As I said earlier, I have put a lot of effort into the mathamatics of this one. One of the goals was the perfect low flow block, I believe this, or something like it, is it. Another was to extend the "C/W vs 'h' crossover" point
Now to tweak and test further to try and refine the concept. It has a lot of copper there to provide thermal inertia. Might be a dark horse advantage.

I think that if one were to summarise the spherical concept it would go something like this.

1. In a low flow scenario it is unbeatable. (according to my interpretations)
2. It could be dirt cheap if made on a lathe. (but two pieces)
3. Can be made with a low pressure drop with very little performance loss. Not really sure about this, need emperical data.

But. 4. Very little performance gain from a stronger pump or refinements to convection structure geometry. It hit's a performance ceiling.