Correlation between hydraulic loss and characteristic vorticities in a mechanical pump

Abstract

The correlative mechanism between the flow loss and vortex evolution involves the efficiency and stability of space operations during fuel transportation in the on-orbit refueling and circulation systems. This study described detailed hydraulic loss and characteristic vorticity by adopting the entropy wall function and local hydraulic loss rate method that included dissipation and transportation effects. Combined with the correlation analysis, characterized vortex parameters and the distributions of dissipated and transported loss were compared based on the enstrophy method and rigid vorticity transport equation. The results exhibit that although dissipated hydraulic loss occupied a main proportion of the total loss, the transported loss cannot be ignored. The enstrophy for shear vorticity and vorticity transport strength of rigid vorticity are the dominant factors affecting the dissipation and transportation effects and hydraulic loss, respectively. Both dissipation and transportation effects of hydraulic loss are strongly related to shear enstrophy and weakly related to enstrophy for rigid vorticity. However, the correlation between the transport strength of rigid vorticity and the two effects of hydraulic loss was significantly enhanced. Based on this, four sub-items of rigid vorticity transport strength, including rigid vorticity stretching, vorticity dilatation, pseudo-Lamb vector, and viscous terms, were further investigated to elaborate the source of hydraulic loss. The correlations between the pseudo-Lamb vector with transported hydraulic loss were almost identical to that of rigid vorticity transport strength, indicating that the transported hydraulic loss is mainly derived from the shearing motion and local acceleration of vorticity.