| 摘要 |
A method for protection of a centrifugal pump against cavitation is performed by intake of a part of liquid from the pressure pipe and its feeding it to the suction pipe of the working pump. Suction pipe is made of two parts that are connected via flanges, between which is arranged an inter-flange space closed from outside. Exit from this space inside the suction pipe is formed as an annular slot nozzle in the plane perpendicular to the axis of the suction pipe. The left border of slot nozzle is straight stepped, and the right border, from the side of the working pump is curved with rounding inside the pipe in the direction of the pump providing the exit of a pressure flow from the inter-flange space as a thin wall-adjacent film. Due to Coanda effect the film wraps around the curved surface of a slot nozzle and goes straight in the wall-adjacent layer of the common flow thus forming a lubricating environment used to reduce the vortex near-wall formations on the projections of roughness of the pipe surface. Thus, the pressure losses are reduced at the suction pipe and at the same time, thanks to this protraction of a flow, is provided a greater volume of liquid of suction by a working pump. |
