Quote:
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Originally Posted by WAJ_UK
There is a bit more to water jet impingement than whether or not the flow is turbulent. It is highly likely that the flow is turbulant anyway at lower reynolds numbers. You need quite a long, extremely smooth pipe for the flow to become turbulant as high as 4000.
But now I'm off to the pub 
Typical student  |
He He He I hope you managed to get yourself properly pi$$ed m8
I used to have my best ideas after two,three tumblers of 18 year old highland single malt
Anyways, what I meant in my post was that turbulence and turbulent flow causes boundary layer to thin down. Jetted water stream is exerting additional localized high pressure causing further thinning of boundary layer over small area (cup). The overall goal is to make boundary layer as thin as possible to achieve otherwise unimaginable conductive heat transfer coeficient (sp?). Optimal distance between cup and nozzle is dependant on nozzle diameter and jet stream velocity. Water exisiting nozzle is shapad like paraboloid function graph due to simple fact that middle of the stream is the highest velocity and the closer to nozzle wals the slower water travels beacuse of friction (viscous) forces (again boundary layer effect). Adjusting distance tries to aim 'peak' of the jet before it starts to turbulate (jet is and must be as laminar in it's flow as possible to obtain the highest speed). The biggest problem with jet design is that it's peak working paremeters windows is quite narrow and that's why Cathar is designing his blocks for certain flow range adjusting z/d accordingly. Imho that's all what could be possibly done in this area.
Looking at the equation I wrote earlier one can clearly see that the next step is to fight for bigger surface area and this is the biggest challange here. Production costs (there are many designs which are MUCH more effective but are exorbitantly more expensive) versus performance ratio is the killer here. Who in his right mind would pay £500 for water block???
I only spent 15 mins on 3D model and it's not yet presentable but I just thought about a clever way to make it feasible to mass produce.
Unfortunately it is going to be yet more expensive than Cather's baby...
T'nite I hope to post my model for you guys to check out and beat the living daylights out of my design