Question

How does the radius and length of a pipe affect vacuum performance?

Answer 1

down vote
As a fluid flows through a pipe it follows the law of continuity which states that Q = A1 V1 = A2 V2 = constant, where Q is the flow rate (cfm), A is the area of the pipe (ft^2) and V is the velocity of the fluid in the pipe (fpm). So whatever you make up in area you lose in velocity and vise versa since Q is constant (30 cfm).

In your experiment here, regarding condition 1 you could substitute in the continuity equation by R1 (Area = 3.14*R^2), you will find your corresponding velocity. In condition 2 that velocity will be a quarter of condition one's velocity value, and so on. Note: the length is irrelevant.

However you must consider one thing. If you reduced the radius to a point when velocity is large enough to make significant noise, which means loss of energy due to friction that could affect the flow rate. So in most possiblities your 30 cfm will not get affected.

Answer 2

Explanation:

Measure the (overall) length (M) and radius (cm) of the pipe Divide the length by the radius, which provides the L/a ratio referenced in the table Find the table entry.