Seeking advice on problems caused by incorrect selection of high-temperature fans
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I am in charge of a foreign engineering project and have run into a problem. The high-temperature fans supplied from within the country (55,000 m3/h, 2500 Pa, 250 degrees) were selected by the fan manufacturer based on incorrect parameters – the selection was made assuming normal temperature conditions (55,000 m3/h, 2500 Pa). What’s even more frustrating is that our engineers approved these fans despite this issue; it’s really unacceptable. The problem occurred at the site; the design principle of this system is to use high-temperature fans to extract the volatile gases from the remote devices, thereby maintaining a negative pressure inside the devices to ensure proper performance. At normal temperatures on site, these fans performed as expected, but at a temperature of 250 degrees, they were unable to extract the volatile gases inside the equipment, and it was not possible to maintain a negative pressure within the device. I’m not an expert in fans, but through various projects I have acquired some basic knowledge about them. According to the formulas related to fans, when a fan designed for low temperatures is used in high-temperature environments, the air volume should remain unchanged; only the wind pressure should decrease. So why does the actual air volume end up being insufficient in practice? In the end, although the problem was resolved by increasing the rotation speed, I still don’t understand why the air volume of the low-temperature fan changes in ways that are inconsistent with theory at high temperatures I hope experts can provide an answer. Thank you.
It’s likely that the gas density changes at high temperatures, which affects the performance of the fan! !
The fan is selected based on its flow rate at normal temperatures. When the temperature rises, the gas expands, and the actual volume of gas in the system becomes much larger than it is at normal temperatures (in this case, approximately 13 times larger). If the fan is too small, its output is insufficient, and as a result, a negative pressure cannot be established in the high-temperature system. Increasing the fan’s speed on-site is one option, but it’s not clear whether the manufacturer has taken this into account; if the fan operates at an elevated speed for a long time, its lifespan could be affected, and an accident resulting from that would be serious.
It shouldn’t be that many times; the ratio of the volume of gas at 250 degrees to that at room temperature is around 1.92 times. In reality, the fan chosen is too small, so a negative pressure cannot be achieved. By how many times does increasing the rotational speed affect it, and does it have an impact on the fan’s service life?