# How to choose a fan for open circuit wind tunnel?

• help_pls
In summary, a fan with a flow rate of 5100 cfm and a pressure difference of -8 kPa will work for the wind tunnel.
help_pls
Hi all,

I am trying to design a open circuit wind tunnel, and I've got to the point where a fan should be selected. However, I am not familiar with fans at all, so I am wondering if you could help me!

My understanding is that the fan selection process is quite similar to the pump selection process; create a system friction loss curve (pressure vs flow rate) and match that curve with the fan performance curve (pressure vs flow rate), and then the intersection point will be the operating point. Is that correct?

So for my wind tunnel, CFD analysis using ansys aim tells me that with a desired volume flow rate of 5100 cfm, the total pressure difference between the inlet and right before the outlet is -8 kPa, or -32 WC. Does that mean that, doesn't matter if it is an axial fan or a centrifugal fan, or if it located upstream or downstream, I just need to look for a fan that can generate 5100 cfm against 32 WC of pressure?

Thank you

help_pls said:
Hi all,

I am trying to design a open circuit wind tunnel, and I've got to the point where a fan should be selected. However, I am not familiar with fans at all, so I am wondering if you could help me!

My understanding is that the fan selection process is quite similar to the pump selection process; create a system friction loss curve (pressure vs flow rate) and match that curve with the fan performance curve (pressure vs flow rate), and then the intersection point will be the operating point. Is that correct?

So for my wind tunnel, CFD analysis using ansys aim tells me that with a desired volume flow rate of 5100 cfm, the total pressure difference between the inlet and right before the outlet is -8 kPa, or -32 WC. Does that mean that, doesn't matter if it is an axial fan or a centrifugal fan, or if it located upstream or downstream, I just need to look for a fan that can generate 5100 cfm against 32 WC of pressure?

Thank you
Yes, but 32" is a ton of static pressure. It isn't easy to find a fan for that and will require at least 35hp.

help_pls
russ_watters said:
Yes, but 32" is a ton of static pressure. It isn't easy to find a fan for that and will require at least 35hp.
Ok, thank you!

russ_watters

## 1. What factors should I consider when choosing a fan for an open circuit wind tunnel?

When choosing a fan for an open circuit wind tunnel, you should consider the required flow rate and pressure, the desired tunnel velocity, the size and shape of the tunnel, and the power and speed of the fan.

## 2. How do I determine the required flow rate and pressure for my wind tunnel?

The required flow rate and pressure can be determined by the size and shape of the tunnel, the desired velocity, and the type of experiments that will be conducted in the tunnel. It is important to consult with an experienced engineer to accurately determine these values.

## 3. Is the fan's power and speed important when choosing a fan for an open circuit wind tunnel?

Yes, the fan's power and speed are important factors to consider as they determine the amount of air the fan can move and the velocity it can achieve. It is important to choose a fan with enough power and speed to meet the required flow rate and pressure for your wind tunnel.

## 4. Are there different types of fans that can be used for an open circuit wind tunnel?

Yes, there are different types of fans that can be used for an open circuit wind tunnel, such as axial fans, centrifugal fans, and mixed flow fans. Each type has its own advantages and disadvantages, so it is important to choose the one that best suits your specific needs.

## 5. Can I use any fan for my open circuit wind tunnel?

No, not all fans are suitable for use in an open circuit wind tunnel. The fan must be able to provide the required flow rate and pressure, and should be able to withstand the high air velocities within the tunnel. It is important to consult with an engineer to ensure that the chosen fan is appropriate for your wind tunnel.

Replies
6
Views
1K
Replies
13
Views
3K
Replies
4
Views
3K
Replies
4
Views
4K
Replies
4
Views
3K
Replies
3
Views
2K
Replies
10
Views
5K
Replies
2
Views
2K
Replies
2
Views
2K
Replies
4
Views
2K