# Can the vacuum pump outlet air acts as a blower?

1. Sep 26, 2015

Hi,

I'm wondering if a vacuum pump outlet air could be used as a blower?

I have a small open-type wind tunnel that have been used with the vacuum pump by sucking the surrounding air. Could I use the outlet air from the pump to work as a blow-down wind tunnel?

Thanks

2. Sep 26, 2015

### Staff: Mentor

Yes, but it probably won't have much capacity.

3. Sep 27, 2015

Hi Russ,

4. Sep 27, 2015

### JBA

Capacity is the volume per unit time, or as is standard for air movement CFM (cubic feet / minute), of air that will be delivered through the wind tunnel; and, if you are going to use the same wind tunnel, then your vacuum pump will deliver exactly the same capacity when used in a blow-down arrangement.
With a wind tunnel, the important relationship is that the the wind tunnel air velocity through the test section is directly proportional to capacity.
Mathematically, Velocity through the test section = CFM / cross sectional area of the test section.

As a note, regarding your potential conversion, the primary reason that a vacuum type air movement is used as a part of the design that insures the most laminar (nonturbulent) air flow possible through the test section of the tunnel while reducing the overall length of the tunnel. Generally, any type of blower is going to introduce some type of turbulence to the air stream in the tunnel; which, in turn is combated by a long tunnel inlet and some form of straightening vanes. But those two items can introduce air flow disturbances all their own due to potential turbulence origins due to flow friction between the air flow and the tunnel walls and even the surfaces of the straightneing vanes, particularly if high air velocities are required for the testing.

I hope this helps, if you have any more questions? simply ask.
PS Fluid and gas flow are one of my more knowledgeable areas; and, one of my high school science fair projects (some 60 years ago) was a (large) table top high capacity recirculating wind tunnel; that recieved the second place award.

5. Oct 24, 2015

### Raam

Hello,

I want to reduce the pressure to 23 mbar inside the container. Is it possible to achieve with the help of vacuum air blower or should I go for industrial vacuum pump ?