Numerical Investigation on the Spatiotemporal Correlation between Hydraulic Loss and Vortex at Turbine Mode of a Pump-turbine

Abstract

Abstract Hydraulic loss and vortex analysis are two most widely-used methods investigating flow characteristics from macroscopic view and microscopic view respectively although the correlation between these two methods are still not fully clarified. Based on kinetic energy equation and Boussinesq hypothesis, hydraulic loss is resulted from the joint work of the dissipation loss and the transportation loss in flow domain while vorticity can be further divided into local rigid rotational part and deformational part with the help of the newly proposed concept Liutex. Thereafter, enstrophy as well as vorticity transport intensity is selected as the count part of hydraulic loss through dimensional analysis. Finally, the spatial correlation between hydraulic loss and vortex evolution in small guide vane opening at turbine mode is analyzed with the help of SST k–ω model and the temporal correlation at runaway point is analyzed through DES model. For spatial correlation, the dissipation loss and transportation loss are mainly caused by the deformational enstrophy Ω S and the rigid vorticity transport intensity T R , respectively. For temporal correlation, the correlation order nearly remains unchanged while the degree of correlation decreases to some extent. Based on our work, the hydraulic loss caused by different structure of vortex can be quantified and compared.