Macroscale and microscale fluid mechanics in rotary pumps.

摘要

The present study examines macroscale and microscale fluid mechanics in rotary pumps. The rotary pumps considered are the rotary shaft pump (RSP), single-disk viscous pump, and the double-disk viscous pump. The general configuration of the RSP is an axial inflow---radial outflow centrifugal pump. The single-disk and double-disk viscous pumps employ one or two disks to move fluid by imposing viscous shear forces on the fluid.; Behavior of the RSP is examined for a pump impeller diameter of 2.38 mm and blade height of 380 mum, with different number of impeller blades and blade orientations. The pressure rise and flow rate of this pump are characterized. Nondimensional head and flow rate, and hydraulic efficiency are discussed. The dimensional pressure rise and flow rate characteristics are greater than many different micropumps of similar size.; Flow characterization and performance of the double-disk viscous pumps are examined for disk diameters of 2.38 mm, and a gap between the disks of 103 mum. Effects of scaling and microscale phenomena on the flow rate and pressure rise of the single-disk viscous pumps are examined for different disk diameters of 2.38 mm, and 4.76 mm, and gap heights from 6.85 mum to 246 mum. Analytical expressions are derived that describe the integrated values of flow-rate and pressure rise through the pump chamber with and without slip flow and non-Newtonian fluid behavior, and are a good representation of the experimental data. The effects of scaling are examined by comparing the flow rate and pressure rise of the single-disk and double-disk viscous pumps, and different macroscale viscous pumps. Effects due to thermal creep, viscous dissipation, compressibility, and variation of fluid properties are generally found to be either relatively small, or insignificant. A new method of deducing the tangential momentum accommodation coefficient is also presented.; The information provided by this research may be used to improve the design of rotary micropumps. The RSP, single-disk viscous pump, double-disk viscous pump have applications including drug delivery, pumping of biological fluids, electronics cooling, micro-total analysis system (mu-TAS), and other integrated fluid systems.