Basic basic questions

[xxw589]

Why flowbench test should done at a fixed depression??
It seems no one have explained it. I can't answer my supervisor this question.

[jfholm]

One reason I test at one depression if for repeatability. Also so you have a standard to reference. The higher the depression you can test at will probably be better. Most test at 28" because it is an industry standard. The Pro teams that can afford to build a high depression bench test at 60" h2o and much higher.

John

[jfholm]

Another obvious reason to flow at a fixed depression each time, and the same depression, is to see if you get legitimate changes. There are two ways to get more air through an opening, increase the size or increase the pressure. so if you flowed at 10" one time and then flowed at 28" the next you would not know what your modifications did in the port. Just changing to 28" h2o and not doing anything else will increase the CFM through the port over 10". So if you want to see what your modifications to the port have done always use the same set depression from one test to the other.