Analysis and prediction of suspension force characteristics in a scalable hydrodynamic suspension micropump

Traditional contact-bearing pumps suffer from low power density. The reason is that inherent bearing wear issues restricts their rotational speed. Although hydrodynamic suspension pumps achieve wear-free operation at high speeds, existing designs rely on complex grooving processes and high-precision machining to secure adequate suspension force. This study proposes a novel groove-less hydrodynamic suspension micropump (GL-HSMP), which eliminates the need for grooves on bearing surfaces and features relatively large designed clearances in both radial and axial directions. The simple structure and low production cost make it suitable for scalable manufacturing. ‌To clarify the suspension mechanism of the GL-HSMP, a force analysis was conducted on the rotating components and a numerical simulation model was established for the complete flow domain. To further verify the versatility of the GL-HSMP across various operating conditions, the established numerical model was used to predict the suspension force characteristics at different rotational speeds, fluid viscosities, and flow rates. The results demonstrate that the GL-HSMP enables suspension through hydrodynamic lubrication in the radial direction and centrifugal effects in the axial direction. Moreover, stable suspension can be achieved under all investigated conditions. Finally, we fabricated a GL-HSMP prototype and built an experimental test rig. Experimental results demonstrate that the prototype achieves a power density of 38.54 W L-1 at 22,000 revolutions per minute (RPM), surpassing leading industry products. Furthermore, hydraulic performance from experiments and simulations shows good agreement, validating the effectiveness of the simulation model.