A method for predicting the fatigue life of water pump blades and determining the optimal distance between them and guide vanes

Abstract

A method for predicting the fatigue life of water pump blades and determining the optimal distance between them and guide vanes, belonging to the technical field of reliability and durability of power machinery equipment, including determining the dangerous cross-section and dangerous point of fatigue fracture of water pump blades, numerical simulation and analysis of flow fields in different working conditions of water pumps CFD calculation of pulsating water pressure distribution on the blade surface, calculation of alternating stress at the dangerous point of the root section of the pump blade, calculation of fatigue life of the blade under different working conditions of the pump, calculation of the alternating stress and fatigue life of the blade at the dangerous point when the distance between the pump blade and the guide vane is different, comprehensive Considering the cost of replacement, disassembly, assembly and maintenance of blade fatigue fracture during the service life of the pump equipment, the impact of pump efficiency changes on operating costs caused by spacing changes, and the impact of pump axial dimensions on installation layout, the optimal spacing between blades and guide vanes is finally determined. The invention can accurately predict the fatigue life of the blades of the axial flow pump and the guide vane type mixed flow pump, optimize the distance between the blades and the guide vanes, and improve the fatigue durability of the blades.

Description

technical field [0001] The invention belongs to the technical field of reliability and durability of power mechanical equipment, and relates to a method for predicting blade fatigue life and determining the optimal distance between the guide vane and the guide vane under the full operating conditions of an adjustable axial flow pump and a guide vane mixed flow pump. It is the prediction and calculation of the fatigue fracture life of the blade due to the dynamic and static interference with the guide vane when the water pump is running at different lifts and different blade angles. The optimal blade and guide vane are determined by comprehensively considering the fatigue fracture life of the blade, the energy performance of the water pump and the axial size of the water pump. method of spacing. Background technique [0002] Axial flow pumps and guide vane mixed flow pumps have the characteristics of high specific speed, large flow, and low head. They are mainly used in field...

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Problems solved by technology

[0002] Axial flow pumps and guide vane mixed flow pumps have the characteristics of high specific speed, large flow, and low head. They are mainly used in fields such as agricultural irrigation and drainage, sewage discharge, water transfer, thermal power plants and nuclear power cooling and circulating water. The impeller blades are water pumps The core component of energy conversion, in order to meet the needs of operation, the installation angle of the blade can be adjusted. The blade is fixed by inserting the blade shaft at the root into the hub of the impeller. It is a cantilever structure. When the water pump is running, due to the dynamic and static interference of the guide vane not far from the blade outlet The pressure pulsation occurs on the surface of the blade, and the blade generates alternating stress under a large stress level. In actual production, cracks or even serious accidents often occur in the blade of the water pump, and the life of the blade is far lower than its rated life. , leading to frequent fatigue fracture accidents, affecting the normal operation and function of the pump

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