A low specific speed impeller and its blade design method

Abstract

The invention discloses a low-specific-speed impeller and a design method for a blade of the low-specific-speed impeller. Both a front cover plate and a rear cover plate are of disc structures. The blade is designed according to the method that a column and twisting are combined, namely, a working face (4) or a back face (5) adopts a form of a backward bending column blade and the other side adopts a backward bending blade twisting mode, and therefore the blade accords with the law of fluid motion, reduces hydraulic loss, and improves efficiency of a low-specific-speed centrifuging pump. The thickness of the inlet edge, close to the front cover plate, of the blade is 2-3mm, the thickness of the inlet edge, close to the rear cover plate, of the blade is 5-7mm, and therefore sand mould casting lifting precision is improved, inlet flow passages can be partially blocked, and therefore blade inlet excluding coefficient is reduced, and the non-overload characteristic of the low-specific-speed centrifuging pump is improved. The low-specific-speed impeller and the design method for the blade of the low-specific-speed impeller can be applied to the field of efficient non-overload low-specific-speed impeller designing.

Description

technical field [0001] The invention belongs to the field of centrifugal pumps, and in particular relates to a high-efficiency, non-overloaded low-specific-rotation-number centrifugal pump impeller related technology. Background technique [0002] Low specific speed centrifugal pumps are widely used in agricultural irrigation and drainage, urban water supply, mining, petroleum and petrochemical fields of the national economy due to their small flow and high head performance characteristics. Low specific speed centrifugal pumps generally refer to centrifugal pumps with a specific speed of 30 to 80. The outer diameter of the impeller is large, and the width of the blade outlet is small, so the flow path is long and narrow. Usually, it is in the form of cylindrical blades that are easy to draw; disc friction The loss and hydraulic loss are large, and the efficiency of the pump is low. It is one of the energy-consuming equipment in the industrial field. Moreover, the operation ...

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Problems solved by technology

Moreover, the operation stability of the pump in the system is not high, and it is easy to cause overload when operating in a large flow area, shortening the service life of the pump

[0003] At present, the impeller of low-ratio pumps usually adopts the form of cylindrical blades, which is convenient for casting and processing. However, the hydraulic efficiency of the pump is low and overloading is easy to occur; if the impeller of the pump is twisted, the efficiency of the pump is higher, but it is not conducive to casting.

There is no design method for the impeller blade structure regarding improving the efficiency, no-overload performance, and casting process of low-ratio centrifugal pumps

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