Regarding vacuum pumping with a gas pump
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The principle of a gas pump is generally explained as follows: according to Bernoulli’s equation, the throat section is narrow, resulting in high kinetic energy and low static pressure, which creates a vacuum; thus, the gas inside the container to be pumped is drawn out. So what’s the question? No matter how low the static pressure in that place is, its mechanical energy is definitely greater than that of the atmospheric environment; then why is the gas inside the container drawn out? I have always believed that the basis for determining the direction of fluid flow is mechanical energy rather than pressure. Please, an expert, explain how Bernoulli’s equation applies in this context, focusing on the line from the vacuumed container to the throat of the gas pump.
At its core, it’s all about energy conversion! Energy must definitely be conserved! There are also those named after air pumps; they must be predecessors from the 60s-80s! We hardly ever hear this word these days! The normal Bernoulli equation is sufficient; be mindful of the differences in flow velocity caused by varying pipe diameters at the inlet and outlet.
You’re wrong in your judgment; we just need to use whatever name the leader says. Also, your answer is off-topic.
Without a gas extractor, the gas is released directly into the air, so no negative pressure is created in the container. With a gas extractor, negative pressure can be generated; this means that the mechanical energy at the throat area must be lower than that of the surrounding air. If that’s the case, the gas at that location cannot be discharged into the atmosphere. Are the two Bernoulli calculations for the specific point at that location in the throat not consistent?
I think it must be due to the fluid boundary layer.