The issue of wind pressure in fan selection

“With so many fans available, which one is the best choice for me? ? ” Have you ever felt at a loss when faced with a fan of that model? Now, Jinlan fans will tell you some little ‘tricks’ regarding fan selection. As for why it’s a less conventional approach, it is entirely the result of insights gathered by our company’s marketing team based on practical experience and customer feedback, and it is provided solely for the reference of those in the initial selection process. ■Warehouse ventilation: First, determine whether the goods stored there are flammable or explosive items; for example, in paint warehouses, explosion-proof fans must be used. Secondly, depending on the level of noise requirements, one can choose a rooftop fan or an eco-friendly centrifugal fan; (there is even a type of rooftop fan that starts up using wind power, which helps save electricity as well). Finally, depending on the required air exchange volume in the warehouse, the most common axial flow fans of type SF or exhaust fans of type FA can be selected. ■Kitchen exhaust: First, for kitchens where the fumes are exhausted directly indoors (that is, with the exhaust outlet located on the indoor wall), an SF-type axial flow fan or an FA-type exhaust fan can be chosen depending on the amount of fumes. Secondly, for kitchens with heavy oil fumes that must travel through long pipes with bends, it is highly recommended to use centrifugal fans (the 4-72 model is the most common, while the 11-62 model, which is low-noise and environmentally friendly, is also very useful). This is because centrifugal fans generate greater pressure than axial flow fans, and since the oil fumes do not pass through the motor, it is easier to maintain and replace the motor. Finally, it is recommended that kitchens with strong cooking fumes use both of the above solutions together for better results. ■Ventilation in upscale establishments: For the ventilation of upscale places such as hotels, tea houses, coffee shops, card rooms, and karaoke bars, conventional fans are not suitable. Firstly, for the ventilation of small rooms, connecting the ventilation ducts to a central ventilation duct allows the use of FZY series small axial flow fans, which can be chosen to balance appearance and noise levels. These fans are compact in size, come in plastic or aluminum housings, and offer both low noise levels and high air flow rates. Secondly, from the perspective of stricter requirements regarding air volume and noise, a fan box is the best choice. There is sound-absorbing foam inside the box, and connecting it to a central ventilation system can achieve a significant noise reduction effect. Finally, as a supplementary note, for indoor ventilation in gyms, it is essential to choose FS-type industrial electric fans with high airflow capacity, rather than SF-type floor-mounted axial flow fans. This is for considerations regarding appearance and safety.

I’m not trying to choose a fan right now upstairs; haha, the ad was wasted then. By the way: why isn’t anyone discussing this issue? Is it maybe too simple? :L

You are absolutely right, but generally, due to the low density of gases, even when there is a significant difference in speed, the change in dynamic head accounts for only a small proportion of the total change in head pressure! It can be ignored in rough calculations, but if an accurate calculation is desired, the change in dynamic head must be taken into account! The inlet dynamic pressure is calculated as the dynamic pressure head based on the inlet flow velocity! This post was last edited by lss_bms on 2008-6-5 23:09]

Fan total pressure: PtF = P2 – P1 + 1/2*ρ*(c2^2 – C1^2). Fan static pressure: PsF = P2 – P1 – 1/2*ρ*C1^2. What do the symbols in these formulas mean? Please tell me, it’s urgent

The total pressure is PtF, and the static pressure is PsF

What determines wind pressure?