External Gear Pump for Wind Turbine Water System
As part of our wind turbine project, I designed and fabricated a custom external gear pump to meet the team’s requirement for a fully mechanical, water-powered function. After considering alternatives such as Archimedes screws, centrifugal pumps, and lobe pumps, we selected an external gear pump for its low start-up torque, compact footprint, and straightforward driveshaft integration.
Design & Analysis
Developed a stacked-gear assembly with plastic gears, Delrin shim plates, and wave disc springs, sealed with an O-ring and rotary seal to prevent leakage.
Modeled pump performance using CFD and analytical torque-flow equations, validating predictions by comparing CFD velocity contours with physical flow rate testing.
Achieved close correlation between simulated and experimental results (e.g., 1.55 m/s predicted vs. 1.52 m/s measured discharge velocity at 800 RPM).
Fabrication
Machined the aluminum housing and lid on the Bridgeport mill for precise bore and bearing fits.
Laser-cut Delrin shim plates for water compatibility and low friction.
Maintained tight tolerances on locational pins to ensure shaft alignment between housing and lid.
Integrated ¼” NPT fittings for simple tubing connections.
Outcome
The final pump delivered consistent rotation at ~1 Nm torque, maintained a watertight seal, and provided accurate displacement per revolution. Although frictional losses exceeded predictions, the project successfully demonstrated a fully mechanical, in-house fabricated pump with validated flow performance.
