Thanks for the reply. I have uploaded a diagram of what I am working on. It is a screw chiller for olives. The idea is that the cold water comes in from a manifold in the bottom. The water flows through the outer shell into the perforated drum. Water dams prevent the water from short circuiting, so to get out it must go through the perforated drum first. The water will flow into then out of the perforated drum in a dewatering area. The drum turns very slowly so the olives have a retention time of 5 minutes. The water dams only go halfway up the drum, so if the flow is too high the water can spill over the top. The question I am trying to answer is how much flow can I push through the drum? Or, alternatively, what percent open do my perforations need to be for the flowrate I've chosen? The outer drum is 36" and the inner perf. drum is 30". I am going to extend the length a little to add a dead spot in the screen just before the dewatering area so that the water can pile up higher before dewatering. Otherwise the water level will rise and fall as the auger flights turn past the last water dam.
I hope this makes sense. Thanks for your time.