Validation of the numerical model of the vane system of the axial-flow pump OD-2

Abstract

A numerical model was developed, which was used to calculate the main operating parameters of an axial-flow pump in a non-stationary setting using segmented geometry consisting of one rotor blade and stator and a k-ε turbulence model. Calculations were performed for the entire range of flow-rates of the head characteristic of the OD-2 axial-flow pump. The obtained calculated characteristics (head, efficiency) are compared with the data of physical tests of the pump. Qualitatively similar calculated analytical dependencies of the head characteristic and efficiency values with the curves of a real pump were obtained, but quantitatively, an increase in the divergence between the characteristics with an increase in the flow-rate is observed. Thus, the divergence between the calculated and actual head is 15-30% at a feed rate of less than K_Q = 0.4, which is an acceptable result for engineering goals. At a flow-rate above, a significant increase in the divergence between the head is observed. Analysis of the static pressure distribution near the rotor blades obtained using a numerical model showed the presence of physically unreliable rarefaction zones, which indicates conditions of intense cavitation in reality. This makes such numerical models that do not take into account the effect of cavitation of limited applicability for obtaining the characteristics of waterjet pumps. To reduce the divergence between the results of numerical modeling, it is necessary to develop a model taking into account cavitation, as well as to use more computing resources.