After doing some calcs, it's actually worse than I thought. Based on even sized channels for the "arms" radiating from the center and a smooth increase in size from start to end for the outside channel, here are the relative flow numbers in percentages, with Arm1 being closest to the outlet:
Arm1 51%
Arm2 27%
Arm3 13%
Arm4 6%
Arm5 2%
Arm6 1%
Arm7 & 8 < 1%
Couple of other pieces of info:
To get
anywhere close to balanced you have to do some major changes.
If you have a 1/2" center "hole" for the inlet, the maximum width of the arm opening at that point is 0.196" without overlap. A 1/2" hole has a perimeter of 1.5708". Divide that by 8
If you make this in a 2"x2" block area, between the 1/2" inlet area and the 1/2" outside channel at it's widest point, you don't have a lot of room left for the arms. Your best bet will be to use the depth of the channels to get the flow up.
Last thing - the pic I did was to go on top of a block. If you didn't already, look at the link to the
original sight that Digital referenced at earlier in that thread. In your case, all the top would be is a rectangular "box" with 8 holes drilled in the bottom to feed the output of the arms up and 1 in the center for the inlet pipe to go through, then the "top" has 2 holes, one for the inlet, one for the outlet. Not really a hard piece to make at all. Just a box with holes in it
After looking at the ratios needed for balance based on your original block design, this alternate way would actually end up being
much easier.