We have a storage tank with a single Central Vent (with goosenecks) and 8 peripheral smaller vents (with goosenecks) on the roof of a storage tank.
The idea is to have natural recirculation; The hot vapor from inside the tank shall be discharged through the bigger central vent and the cooler air from atmosphere is sucked in through the smaller peripheral vents.
However, this is not happening. Hot fumes are being discharged through the peripheral vents also.
Hydraulics of these vent lines were checked and a third party assessment of line hydraulics has also been performed. There is no problem with the hydraulics of these lines.
What can be the reason behind this unexpected circulation of air?