by Tony » Fri Feb 15, 2008 5:34 pm
Make the hole large, so that the thickness of the bulkhead is well clear of the down stream flow wake, so it is not going to interfere with the natural flow coefficient..
The edges of the hole only need to mechanically support the orifice plate, so if the orifice plate is fairly sturdy, the supporting hole for it can be made quite large.
Difficult to say really, but maybe if your material is going to be 3/4 , perhaps 3/4 inch larger all around than the orifice hole ? So 2.5 inch hole, plus 1.5 inches = 4 inches minimum. Even five inches would be practical.
That is only a suggestion, but that would be my approach.
Your flow bench will end up being unbelievably heavy, so put some very robust casters underneath.
My own flow bench is made from one inch MDF, and has a large cast iron cased air blower. The whole thing weighs in at around 1,150 bs ! It is difficult to move, even on wheels. Yours should be nowhere near that weight, but it will still end up being a lot heavier than you probably expect.
Just keep in mind the very high forces that several psi of air pressure can generate. Better safe than sorry.
Also known as the infamous "Warpspeed" on some other Forums.