The cause of instability in the oil drum pump

Assuming that the oil drum pump is at a certain small flow rate lower than the design flow rate, since the liquid flow of the impeller flow path is affected by the work of the blades, the liquid flow close to the working surface is strongly increased by the blade and close to the non-working surface. The flow of the liquid is weakened by the work of the blade, so that it is easy to separate the boundary layer on the non-working surface of the blade of the oil drum pump, that is, the reverse flow of the liquid flow.
Assuming that the oil drum pump is at a certain small flow rate lower than the design flow rate, since the liquid flow of the impeller flow path is affected by the work of the blades, the liquid flow close to the working surface is strongly increased by the blade and close to the non-working surface. The flow of the liquid is weakened by the work of the blade, so that it is easy to separate the boundary layer on the non-working surface of the blade of the oil drum pump, that is, the reverse flow of the liquid flow.

Since the flow velocity in the separation zone of the drum pump is much lower than the flow velocity in the main flow zone, the separation blocks the flow in the passage so that a part of the flow enters the lower direction along the direction of rotation. , causing the flow direction of the flow channel to decrease the angle of attack to weaken the separation of the non-working surface boundary layer of the flow channel.

The other part of the liquid flow enters the lower first stage against the direction of rotation, so that the flow angle of the flow path increases, and the boundary on the non-working surface of the flow path is separated, so that the stall area rotates along the impeller. The direction propagates. When the boundary layer separation occurs in the flow channel of the oil drum pump, strong turbulence and vortex are generated inside the separation zone. The flow loss greatly reduces the head and efficiency and the oil is promoted due to the occurrence, development and weakening of the stall zone. The outlet pressure of the barrel pump produces a pulsation, that is, the oil drum pump is unstable.

Article from: http://?449.html China Hardware Business Network http://news.chinawj.com.cn Editor: (Hardware Business Network Information Center) http://news.chinawj.com.cn

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