What is precession? What is the significance of fluid pre-rotation for centrifugal compressors or centrifugal pumps?
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What is precession? What is the significance of fluid pre-rotation for centrifugal compressors or centrifugal pumps? When studying the Euler equations in fluid dynamics recently, I came across a statement stating that the fluid entering the inlet of a compressor or pump has no pre-rotation, that is, C1u=0. There is very little information on this topic, and I still don’t understand it; I’m seeking advice from everyone here! Pre-rotation can be installed on centrifugal compressors or pumps; is it possible to do the same with reciprocating ones? What are the advantages and disadvantages of pre-spin?
Pre-rotation can be provided on centrifugal compressors or pumps, while it is not necessary for reciprocating types. Pre-rotation is used to reduce surging at the inlet of centrifuges or centrifugal pumps; it is not required for reciprocating or screw-type machines
It is mainly convenient to start and adjust.
This post was last edited by lovestory on 2011-6-26 23:04. Reply 1# lisizhen2010: Pre-rotation is mainly used to prevent cavitation; the inlets of the high-speed pumps in our factory all have 2 of these
Pre-rotation refers to the situation where, as the fluid enters the blade, it does not flow axially, but rather has a tangential, also known as circumferential, velocity component. The presence of this velocity component causes changes in both the magnitude and direction of the fluid’s relative velocity with respect to the impeller. For example, in the absence of pre-rotation, the maximum velocity of the fluid relative to the impeller is 280 m/s with an angle of attack of 0. With pre-rotation, at constant rotational speed, the maximum velocity of the fluid relative to the impeller may drop to 250 m/s or rise to 320 m/s, with an angle of attack of -4 degrees or +4 degrees; this results in significant changes in the aerodynamic properties of the impeller machinery, thereby enabling it to adapt more effectively to different operating conditions. Precession is divided into positive precession and negative precession. QQ:875351942。