A centrifugal piezoelectric pump with helical channel for low-shear, high-precision delivery of high viscosity fluids

To meet the demands of microfluidic systems for micro-volume, low-shear, and high-precision delivery of high-viscosity fluids, this paper presents a centrifugal piezoelectric pump with helical channel driven by a circular-motion mechanism. The pump uses two-phase excitation signals to drive the piezoelectric vibrator into a conical pendulum motion. This conical pendulum motion generates centrifugal force within the helical channel, which is decomposed into a sustained axial driving force to propel the fluid. Based on this working principle, theoretical equations for the radial driving force and the output flow rate within the channel are derived. A prototype was fabricated, and both output flow experiments and multiphysics coupling simulations were conducted to systematically evaluate the pump's performance. The results show that the pump exhibits excellent adaptability to a wide range of viscosities (up to 284.1 mPa s) and maintains a stable output. The maximum output flow rates for water and a high viscosity fluid (284.1 mPa s) are 1.26 ml/min and 4.12 μl/min, respectively, with corresponding flow fluctuation ratios as low as 2.1% and 12.1%. Furthermore, simulation results indicate that during the delivery of high viscosity fluid (284.1 mPa s), the maximum local shear stress inside the pump is only 17.6 Pa. This study provides an effective technical solution for low-damage and high-precision delivery of high-viscosity fluids, with potential applications in biomedical and related fields.