Gas flow velocity under vacuum conditions
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Dear experts: What is the gas flow rate required during design at a vacuum condition of -0.09 MPa? What does it mean in a chemical engineering design manual for pipes with a vacuum level of 650–710 mmHg?
If you convert it to actual pressure, you’ll find the corresponding value; this pressure range is -0.09 MPa, which is what you need
Thank you to the person above. Could someone from an engineering firm explain the difference between vacuum tubes and pipes with a vacuum level of 650–710 mmHg as mentioned in the chemical engineering design manual?
Give it a push; which expert can answer this question?
You mean that, at a vacuum level of 650–710 mmHg, the flow rate in the pipeline should be 80–130 m/s; for other conditions, it should follow the same criteria
The flow velocity in a vacuum tube should be determined based on pressure drop calculations; it can range from as low as 50 m/s to values close to the speed of sound, depending on the pressure drop chosen.
It can’t be generalized either; it depends on the requirements of your device side. I can give an example: Suppose I have a distillation tower that requires a vacuum level of 5 mmHg, while the maximum vacuum level that the selected vacuum pump unit can achieve is 2 mmHg; in this case, the maximum pressure drop in the pipes can only be 3 mmHg. In other words, the pressure drop depends on the vacuum level required at your equipment and the choice of vacuum unit.