Design tools and mechanisms for progressive cavity pumps

Abstract

This thesis presents tools to design progressive cavity pumps (PCPs), with an emphasis on low-viscosity fluids. These models indicate that high speed operation can increase sealing performance, decrease pump size, and eliminate gear-reductions. New models for estimating both laminar and turbulent internal flow and shear losses in these pumps are presented. The new models are capable of estimating pump performance 1000x faster than traditional simulation methods, and do not require empirical calibration, making them 'designer-ready'. A proof-of-concept turbulent PCP was designed using these models. Its volumetric efficiency is within 20% of predicted values. This thesis also presents a novel one degree-of-freedom hypocycloidal bearing to constrain the motion of the rotor for increased performance and control. 3 different bearing topologies have been developed: roller, rail, and flexural. An experimental PCP concept with integrated hypocycloidal rail bearings was developed and tested with efficiencies as high as 45%. Experimental data are compared with a new lubrication theory model which accounts for rotor motion, rotor geometric error, and stator geometric error. The experimental and theoretical results show strong agreement, proving that low-order lubrication theory models are accurate simulation tools. Additionally, performance results from the rail bearing pump and first-order analysis inspire new scaling laws for connecting the volumetric and mechanical efficiency of PCPs. These scaling laws show strong agreement in both turbulent and laminar flows. A new generation of PCPs has the potential to transform irrigation, water purification, oil-sand extraction, among other applications. The new tools required to create these PCPs also have strong implications for how traditional PCPs are designed.