UnVenturi Fan Shroud 40mm

thingiverse

Venturi shroud increases the speed of air flow, but also makes low pressure on the upper side of the fan blades. UnVenturi does the opposite, reduces the air velocity in front of the fan, but equalizes the pressures on both sides of the fan blades. As a result, there is some reduction in the noise produced by the fan. It also increases the life of the fan itself. I must say that there may be a slight decrease in fan flow.