What is the effect of cavitation in centrifugal/piston pumps on the current consumption of the pump?
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I searched online, including on Haichuan, and it was said that cavitation in pumps can cause fluctuations or decreases in current, but the book \"Maintenance Techniques for Typical Mechanical Equipment in Refining and Chemical Enterprises\" states that cavitation in pumps can lead to an increase in current. . . Furthermore, based on our on-site experience, several twin-screw pumps there experienced severe cavitation due to process-related factors, which resulted in very high current levels. Is it because the cavitation phenomenon in screw pumps is different from that in centrifugal pumps?
The effect of pump cavitation on current mainly depends on the specific pump type and operating conditions. Generally speaking, centrifugal pumps and screw pumps differ in terms of cavitation. In centrifugal pumps, when cavitation occurs, air enters the pump and mixes with the liquid, resulting in a decrease in the density of the liquid. Since centrifugal pumps transfer energy based on the density of the fluid, a decrease in density leads to a drop in the outlet pressure of the pump, which in turn causes fluctuations or a reduction in current. In screw pumps, cavitation increases the gas content in the liquid within the pump chamber, resulting in a gas-liquid two-phase flow. Gas-liquid two-phase flow has high viscosity, which increases resistance and requires the pump to generate more power to overcome this resistance. Therefore, when cavitation occurs in a screw pump, the current usually increases. Based on the situation you mentioned, it is consistent with normal circumstances for the twin-screw pump on site to experience an increased current due to severe cavitation. This may be due to the characteristics of the screw pump and the process conditions. Different types of pumps may exhibit varying behaviors regarding cavitation; therefore, when considering the impact of current on pump cavitation, it is necessary to analyze specific situations individually. .
This post was last edited by HLBO on 2023-9-2 at 17:19. Sorry, I replied to the wrong person
Teacher, I know that the formula for calculating the shaft power of a centrifugal pump is flow rate * head * specific gravity / efficiency. But an increase in viscosity of the fluid inside the pump should also increase the fluid resistance within it, so why doesn’t it affect the energy transfer in the centrifugal pump?