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Blackeagle · 02-25-2003, 02:59 PM

I guess I'm missing it Gmat, regarding the percentage of flow per tube. And I could have stated my thinking better in the first post.

My thinking is based on the way pressure/resistence goes up as a square to increasing velocity in tubes.

Thus a 1046 with it's low flow and low head would allow the flow to all go through a small number of tubes. With a system having dual rads and 3-5 blocks flow rate would be well below 1gpm. So here I agree the flow goes through a minimum number of tubes. The velocity per tube would be to low to overcome the resistence differance caused by the added distance to travel in the two tanks.

A MD-20 Z with 7X the head can increase flow in his system to around 2gpm. The incrased velocity would create 5 to 6X the resistence, which would override the slight resistence differance between tubes resulting in a more balanced flow as the resistences caused by velocity in all the tubes would be greater than the differance in resistences caused by increased distance traveled in the two tanks.

Would still not be completely balanced as the distance in tank travel is still there. But that travel factor is now a lesser secondary resistence compared to the resistence from the velocity in the individual tubes.

What is my error or oversight?

My temptation is growing. What would you think about cutting away one brass tank, then replace it with one of plexi? With a outlet at each end with caps for each. Could then test to see the differance caused by diagonal inlet/outlet by alternating which is used. Could test pumps as well. But how to messure differances in flow per tube? Best I can invision is to add a dye to the water and then observe the flow of the dye through that plexi tank. But that is still only a subjective visual observation test. While repeatable, no way to get accurate messurements.

Ideas?

02-25-2003, 02:59 PM	#24
Blackeagle Thermophile Join Date: Oct 2002 Location: U.S.A = Michigan Posts: 1,243	I guess I'm missing it Gmat, regarding the percentage of flow per tube. And I could have stated my thinking better in the first post. My thinking is based on the way pressure/resistence goes up as a square to increasing velocity in tubes. Thus a 1046 with it's low flow and low head would allow the flow to all go through a small number of tubes. With a system having dual rads and 3-5 blocks flow rate would be well below 1gpm. So here I agree the flow goes through a minimum number of tubes. The velocity per tube would be to low to overcome the resistence differance caused by the added distance to travel in the two tanks. A MD-20 Z with 7X the head can increase flow in his system to around 2gpm. The incrased velocity would create 5 to 6X the resistence, which would override the slight resistence differance between tubes resulting in a more balanced flow as the resistences caused by velocity in all the tubes would be greater than the differance in resistences caused by increased distance traveled in the two tanks. Would still not be completely balanced as the distance in tank travel is still there. But that travel factor is now a lesser secondary resistence compared to the resistence from the velocity in the individual tubes. What is my error or oversight? My temptation is growing. What would you think about cutting away one brass tank, then replace it with one of plexi? With a outlet at each end with caps for each. Could then test to see the differance caused by diagonal inlet/outlet by alternating which is used. Could test pumps as well. But how to messure differances in flow per tube? Best I can invision is to add a dye to the water and then observe the flow of the dye through that plexi tank. But that is still only a subjective visual observation test. While repeatable, no way to get accurate messurements. Ideas? Last edited by Blackeagle; 02-25-2003 at 03:13 PM.