How to determine cavitation and gas entrapment on-site
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How can one determine cavitation and gas entrapment on-site? I was really stumped by this issue at the site.
Gas entrapment is likely caused by the presence of gases such as air that are non-condensable. Cavitation occurs when the pressure drops to the saturated vapor pressure of the liquid being transported, causing boiling; the resulting vapor bubbles rapidly condense as the pressure increases sharply during the flow of the liquid from the inlet toward the periphery. This causes the liquid to rush toward the center of the bubble at high speed, generating impacts with very high frequencies and intense instantaneous pressures; this phenomenon is known as gas cavitation.
This post was last edited by hand over VS flow on 2010-4-6 at 13:00. Cavitation occurs when the liquid being transported partially vaporizes because the saturated vapor pressure at the transportation temperature is equal to or lower than the pressure at the pump inlet (actually at the inlet of the impellers), which causes noise and vibration in the pump. In severe cases, it leads to a significant reduction in the pump’s flow rate, head, and efficiency. The key to avoiding cavitation is to ensure the correct installation height of the pump, especially when transporting volatile liquids at high temperatures. Air entrapment occurs when air is trapped inside the pump, preventing liquid from being pumped out.
Gas binding results in a complete inability to pump liquid, with little harm to the pump. Cavitation still allows liquid to be pumped, but it causes significant damage to the pump. Conceptual things.
There are many discussions about these two concepts on the forum; you can search for them.
These are two concepts with similar phrases but different meanings. Cavitation occurs when the pump is operating and pumping gas, causing the pressure inside the pump to reach the saturated vapor pressure of the liquid. The liquid then vaporizes, and the surrounding liquid droplets rush toward the center of these vaporized droplets at high speeds, exerting significant force on the pump and generating loud knocking sounds. Gas entrapment can be understood as gas inside the pump trapping it; when the pump operates, the presence of gas means that the mixture is not entirely liquid, and as a result, it is not possible to achieve a certain negative pressure (since the density of gas is lower than that of liquid). Without sufficient pressure difference, feeding cannot take place.