Turbulent Taylor-Couette-Poiseuille flow with grooved interference in a high-speed canned motor pump for marine nuclear power platform

The canned motor pump is a critical component in the core cooling system of marine nuclear reactors, responsible for driving crucial fluids such as reactor coolant. Among these, turbulent Taylor-Couette-Poiseuille flow is the most prevalent in the clearance flow of high-speed canned motor pumps. Numerical simulations were conducted to investigate the Taylor-Couette-Poiseuille flow with a radius proportion of 0.934, an axial Reynolds number (Re a ) of 1500, and Taylor numbers( Ta ) ranging from 10 8 to 10 9 , incorporating three different scales of asymmetric triangular grooves on the inner wall. The study demonstrates that incorporating small-sized grooves (W0.1H0.05) into the structure significantly decreases torque, achieving a maximum drag reduction rate of 11.39 %. The large-sized groove structure (W1H0.5) significantly increases the axial friction coefficient, with a peak rise of 119.27 %. The grooves reduce the velocity gradient on the inner wall, and within the grooves, the negative axial velocity contributes to increased axial resistance. As the groove size increases, both radial and azimuthal velocity fluctuations also increase, while smaller grooves are more effective in mitigating these velocity fluctuations. Additionally, it can be observed that the small grooves W0.2H0.1 and W0.1H0.05 reduce the turbulent kinetic energy within the flow field. The velocity structure near the groove top approaches linearity at different rotational frequencies, with a negative peak observed at the groove bottom. With larger groove sizes, the mid-to-high-speed regions of the flow field expand. With increasing rotational frequency, the flow field's velocity stratification alters, characterized by the expansion of vortices outward from the inner wall.