A new two stage miniature pump: Design, experimental characterization and numerical analyses

The objective of the study described here is to explore the possibilities of an innovative two-stage micro pump. The first stage was realized by a micro Rotary Shaft Pump (RSP) with an external diameter of 3 mm and a blade height of 0.4 mm. The second stage, partially integrated in the RSP, was a centrifugal viscous pump with a 4.4 mm external diameter. The numerical and experimental characteristics of two prototypes are presented. Different rotational speeds were tested up to 24,000 rpm, obtaining pressure increases up to 12 kPa and flow rates up to 150 ml/min, corresponding to a head coefficient of 0.12 and a flow coefficient of 0.4. 3D time dependent CFD simulation were also carried out and compared with experimental data. Numerical results allowed to study the flow field inside the pumps and to compute the hydraulic efficiency of the two stages, as well as, to show the distribution of losses inside the pumps.