Microengineered Axial-Flow Pumps and Turbines

Andrew Holmes, Guodong Hong, Mark Heaton

In this project we are developing mm-scale axial-flow turbines that can generate electrical power when placed in an air-stream or other gas flow. The axial-flow geometry is chosen because it allows operation at relatively high flow rates and low pressure heads. Applications are envisaged in areas such as wireless flow sensing and micropower generation.

Current designs are based around a 13 mm-diameter polymer rotor with embedded permanent magnets. The rotors are formed by a combination of UV lithography and excimer laser micromachining, with the laser being used to define the required 3D blade profiles. The rotor is mounted between silicon stator parts carrying multi-layer electroplated copper coils. In addition to producing a range of novel microengineered devices, the project will address more general issues relating to assembly of complex microsystems and implementation of bearings.

The project is funded by EPSRC, and is a collaboration between Imperial College London, Heriot-Watt University, and four industrial partners.

Cross-sectional view of axial-flow turbine

Multi-layer electroplated copper coils on a silicon stator

Polymer rotor formed in SU8 by UV 
lithography and laser micromachining

Prototype axial-flow turboelectric generator