A numerical prediction method for tip clearance cavitation of axial flow pump impeller

Abstract

The invention discloses a numerical prediction method for impeller tip clearance cavitation of an axial flow pump, belonging to the technical field of impeller machinery simulation. It includes the establishment of the internal flow channel of the axial flow pump and the meshing of its three-dimensional watershed, the construction of the numerical calculation model of the clearance cavitation flow, the numerical calculation of the steady cavitation flow field inside the axial flow pump, the solution of the unsteady cavitation flow field inside the axial flow pump, and the numerical predictionand examination of the clearance cavitation region of the impeller tip of the axial flow pump. The invention considers the influence of the local vortex motion of the blade tip clearance on the cavitation flow, by adding the flow parameters reflecting the local rotational motion characteristics of the flow field into the cavitation model, the credibility of the numerical prediction of the cavitation of the impeller tip clearance of the axial flow pump is improved, and the cavitation region of the impeller tip clearance of the axial flow pump can be predicted accurately, which has important theoretical value and engineering practical significance.

Description

technical field [0001] The invention belongs to the technical field of impeller machinery simulation, and in particular relates to a numerical prediction method for cavitation in the vane tip clearance of an axial flow pump impeller. Background technique [0002] In the impeller channel of the axial flow pump, there is a gap between the rotating blade and the pump casing at the outer edge of the blade tip. The gap between the impeller and the tip of the impeller is the concentrated area of ​​cavitation damage in the axial flow pump. Cavitation in the tip gap is the cause of failure of the axial flow pump unit. important factor. Constrained by the geometric scale and complex flow field of the impeller blade tip of the axial flow pump, the experimental test of the cavitation flow field in the gap is expensive, difficult, and limited in data. In contrast, the numerical simulation technology based on computational fluid dynamics has the advantages of obvious. The flow field in...

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Problems solved by technology

[0003] The purpose of the present invention is to propose an axial flow pump for the current large axial flow pump station and axial flow pumps used in the market, the vortex in the blade tip clearance and the vortex cavitation phenomenon caused by it, and the numerical prediction accuracy of vortex cavitation is low. The numerical prediction method of impeller blade tip clearance cavitation can consider the influence of local vortex motion on cavitation flow, and improve the reliability of numerical prediction of axial flow pump impeller blade tip clearance cavitation, which has important theoretical value and engineering practical significance

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