Quote:
Originally posted by Les
Yes the agreement is somewhat scary and probably unreal but worthy of of further investigation.
Wanted to use two values for r
(1)the min value(2.5D) allowed,this gives the max h value,to use as as an "effective impingement area. area".
(2)an r value representative of the bp area (30mm?) to get by manipulation a value to use as "background convection"*.
However as 2.5D(36.25mm) in the 0.57"(14.5mm) case is larger than the bp area I decided,somewhat arbitarily, to use the same r value of 25mm. This 25mm was intended as representative of a 50x50mm bp.Unfortunately mid way thro calcs memory said a more realistic bp was 60x60mm and used this in Waterloo calcs. Probably should redo with r=30mm(and correction of D= 0.0145 not 0.014)but ... ..and quick look showed little difference.
Apologise if this is as clear as mud but .................
Can (and have 1/4 done,somewhere) the two r (and hence two h) sums when nozzle diam approaches 3mm.
Using "the real value of H is 0.013m" get 
Get the same for "the -U values are: D = 0.010, H = 0.005m".
Will "Press (Calculate Now) to calculate anyway"for both cases,but allow a little time ........ slow and oft befuddled brain.
Dunno whether to change r to 30mm.
.* As used in last my post here (but called Wall Jet) http://forums.procooling.com/vbb/sho...5&pagenumber=7
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The Ht. should be between 2 and 12 times D, you are calculating for 1.3XD, decrease D or increase H. Since H is real world I presume, then you can more easily decrease D. As you increase H, r also increases (how to precisely calculate though?), As you decrease D, r should also increase? Overload on the logic circuits
