Regarding the liquid level issue
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A storage tank holds water, with a centrifugal pump connected to its bottom. When the centrifugal pump starts, will vortices form in the water inside the tank, resulting in a lower level in the center of the liquid surface and a higher level around the edges?
I’m not quite sure what you mean Change the status quo? Can changing it from bottom extraction to side extraction work?
If the pipe opening is facing the center of the tank, the phenomenon you mentioned should not occur; at least I have not observed it in practice.
If there are vortices during high flow rates, anti-vortex baffles are generally installed at the tank outlet. The purpose is to prevent the pump from running dry.
How large is the storage tank you are referring to? For large-diameter tanks, unless they have a conical bottom, this situation may only arise at the end of evacuation; generally, this factor is taken into account during design by adding baffle plates. Also, what is the flow rate of your pump? Is the storage tank used compatible with your pump? If it is, and baffle plates are installed as well, such a phenomenon is unlikely to occur.
Why does the phenomenon occur where there are vortices in the water inside the tank, resulting in a lower level in the center and a higher level around the edges? :)
Cans that are pumped out from the bottom are generally equipped with vortex-breaking devices, and during normal operation of the cans, a certain liquid level must be maintained; therefore, the phenomenon you mentioned does not occur.
The experimental setup, with side extraction, should work
It would have to be a really strong pump for it to be that extreme, right?
It won’t happen, unless the liquid level in the tank is very low; and if that happens, wouldn’t the pump get emptied? There should be a device to prevent emptying.
Firstly, the volume of the tank must be large enough, with the liquid storage area providing at least 1–3 minutes of buffer time. Secondly, an anti-vortex device must be installed at the outlet pipe of the container; this should prevent the problem you mentioned from occurring.
No, unless your pump and your storage tank are not compatible – the pump is too large and the tank is too small. In actual practice, such imagination does not exist
This phenomenon occurs only when the pump is too large and the tank design is unreasonable.
Generally not, unless only a small amount of liquid remains at the head level after drawing. But now there are also vortex breakers, so there’s no issue with gas entrainment.
Use a vortex breaker, or install a level gauge on the horizontal pipe
The liquid in the inlet pipe of a centrifugal pump can rotate, which is pre-rotation. Sometimes, the pre-rotation direction is the same as the impeller rotation direction, and sometimes it is opposite. The pre-rotation strength isn’t high; add a baffle, and that’ll do it.
The jar is quite small, right? Also, it’s fine if there’s a slight swirl; it doesn’t affect usage.
Generally, bottom exhausts are rarely used; most are located on the sides. This is mainly because solid particles might enter the pump body from below and cause damage to the impeller
Sure, the storage tank must maintain its liquid level; it won’t be emptied, so that kind of situation won’t occur
Whether a vortex is formed is related to three factors: 1. The flow rate of the liquid pumped by the pump; if the storage tank is very large while the pump’s flow rate is low, no vortex will be generated； 2. The volume and structural design of the storage tank; if the tank has a sufficiently large volume or anti-vortex baffles, no vortices will be generated ； 3. The flow pattern of the liquid inside the storage tank; for example, if the fluid in the tank is rotating counterclockwise and there are no vortex suppressors in the tank, starting the pump at this time can easily lead to the formation of vortices.
No matter how large the groove is, a vortex inhibitor plate is usually sufficient