Hydraulic design method for low-specific-speed overload-free centrifugal pump impeller

Abstract

The invention relates to a hydraulic design method for a low-specific-speed overload-free centrifugal pump impeller. Geometrical parameters of the low-specific-speed centrifugal pump impeller and performance parameters of a design condition point are related together through the method of setting up an equation, the optimal hydraulic performance and the good shaft power characteristic are obtained by adjusting values of the different geometrical parameters, and therefore the designed low-specific-speed centrifugal pump impeller can be free of humps and high in efficiency and can meet the overload-free requirement. A design formula of the main geometrical parameters of the impeller is given and includes the inlet diameter Dj of the impeller, the inlet diameter D1 of blades, the outlet diameter D2 of the impeller, the outlet width b2 of the blades, the number z of the blades, the inlet placing angle beta 1 of the blades, the outlet placing angle beta 2 of the blades, the wrap angle phi of the blades and the real thickness delta of the blades. By the adoption of the low-specific-speed centrifugal pump impeller, it can be ensured that a centrifugal pump can be used reliably under the high-lift and small-flow working conditions and used safely in an overload-free mode under the low-lift and large-flow working conditions.

Description

technical field [0001] The invention relates to a hydraulic design method of a centrifugal pump impeller, in particular to a hydraulic design method of a centrifugal pump impeller with low specific rotation number and no overload. Background technique [0002] Energy is of great significance to the improvement of human living standards and the development of the national economy. It has become an important material basis for the development of a country. With the rapid development of our country's economy and the decrease of global energy, how to save energy has become an issue that people pay more and more attention to. At present, there is a great demand for pump products in China, and 20% to 25% of the annual power generation will be consumed on pump products. Centrifugal pump is an important pump product in fluid machinery. It has the advantages of stable pressure and flow, light weight, compact structure, convenient and reliable operation and low maintenance cost. Du...

AI Technical Summary

Problems solved by technology

[0005] The existing patent No. 90214606.8, titled "A Non-overloaded Low Specific Speed ​​Centrifugal Pump Impeller" proposes that when designing the impeller of a low specific speed centrifugal pump, the geometric dimensions of the front and rear cover plates of the low specific speed centrifugal pump impeller should meet According to the given equation, the low specific speed centrifugal pump impeller designed in this way can meet the requirements of high efficiency and no overload, but this patented technology still has the following two problems: First, the patented technology does not provide the blade inlet The design method of the geometric parameters at the center causes the highest efficiency operating point of the low specific speed centrifugal pump to appear in the large flow area, resulting in a decrease in the efficiency of the design operating point of the low specific speed centrifugal pump; Angle proposed design method, the selected blade wrap angle is too large, which increases the difficulty of impeller casting process

However, the inventor did not provide a systematic and accurate design method for the basic parameters of the impeller of the low specific speed centrifugal pump in this patent, and the design method still largely relies on the original similar design method and speed coefficient method

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