Quote:
Originally posted by Les
Be interested to see the work on which this recommendation is based.
For 1.5mm nozzles results* indicate that h increases as the nozzle/plate*** seperation(H) is decreased from 3mm to 1.5mm.
For other nozzle IDs I keep an open mind until I see some data (or undertand the theory).
However all the calculations I have done with Flomerics** show an increase in h with decreasing H ("down to" and "below" the calculator's lower limit of H=2D)
* http://widget.ecn.purdue.edu/~eclweb/jet_benchmark/
** http://www.coolingzone.com/Content/D...as/fcalc10.htm
*** Ceiling is lowered "along with nozzle" to 1.5mm (In light of Cathar's 12.13 am post)
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I have been looking through that and end up with the same results. So I think I was right going down to 2mm. But think of this. With our pumps that produce low 3 PSI pressure, velocity won't be that much so the distance won't matter until you get to far away. Say 7mm? Use a high velocity in that calc. Then you start to see a BIG difference with distances. I'm thinking as long as it's between 2mm and 6mm you will be ok with our typical pumps and anything inbetween 2mm - 6mm won't make a visual difference. Don't get me wrong, the distance will make a difference but not a difference we will ever notice. Atleast with our pumps. Nozzle diameter does make decent difference.
Now I tried the two blocks again. They both perform different with one being worse. I took both jets out. They both got worse but the difference between the two stayed the same. So this weekend I'll keep trying the nozzle distance from 1mm and up just to see. I have a hunch nothing will make a change because the effect at this velocity is so low to even notice.
After this I see about changing shapes of the nozzle and it's angle.