Using Stator Blades in Accessory Tracts of Hermetic Pumps

Abstract

Centrifugal pumps are the most extensive class of dynamic hydraulic machines, which are commonly used. So-called hermetic pumps, which possess a number of calculation and design features, stand apart among these machines. Rather complicated task is to calculate internal tracts of the hermetic pump, which are used to cool and lubricate its units. The article is concerned with this calculation, namely, the study of the hollow flow. In designing the hermetic pump, when simulating the flow through the accessory tracts, a so-called “lock” effect was detected between the rotor end and the side cover. This effect is caused by a macro-vortex formed in the hollow, which resulted in a significant pressure drop at the inlet of the shaft opening. Such a pressure drop leads to reducing fluid flow through the accessory tracts, which can cause overheating and failure of the engine and bearing units. In view of the large width of the hollow under consideration, to describe theoretically its flow is difficult. Therefore, a numerical simulation is the most accurate way to determine the impact degree of the macro-vortex on the flow process. The article shows a mathematical model used in computer modeling. Presents the images of a flowing part of the accessory tracts and the computation mesh. Also, gives the models to construct a mesh and the boundary conditions desirable to provide hydrodynamic calculation. Then, describes the possible ways to eliminate the “block” effect, i.e. to set an additional impeller, completely change the configuration of a flowing part of the internal tracts, as well as to add the stator blades to the side cover. The latter option was chosen, as the most optimal in terms of labor intensity and manufacturability. Further, to compare the nature of the flow with the blades and without them the article shows pressure distribution fields, vectors of velocity, and turbulent kinetic energy values. All the results obtained, including experimental ones, with errors are presented in the summary table.