Design and Fabrication of a Miniature Turbine for Power Generation on Micro Air Vehicles Team Arman Altincatal Srujan Behuria Carl Crawford Dan Holt Rob Latour Advisor: Dr. Kozak

Overview Project Background and Motivation Project Objectives and Specifications Final Design CFD Analysis Experimentation Results Conclusions

Current Problem The weight of batteries is prohibitive for Micro Air Vehicles (MAVs) Current Batteries –More than 50% of the vehicle weight –Less instrumentation can be attached to MAV MicroTurbines: a Possible Alternative Much greater power to weight ratio Microturbines are being developed at a number of schools Black Widow by Aerovironment MIT’s Micro Turbine Impeller

A Viable Miniature Turbine Impulse or Pelton Wheel Design Compressed Gas Designed to power MAV components Can be produced without MEMS fabrication techniques

Design Goals Objectives Generator should be reusable Design for MAV’S Generator should run for required MAV flight time Specifications 5 watts Minimum torque should be.021 oz-in Generator Temp. should be less than 125°C Blades should spin at minimum of 50,000 rpm

Flow Passages Two jet design Air fitting mounted axially to turbine Identical Passages –Length, Turns –Inlet Conditions Uncontoured converging nozzle design Nozzle machined into the casing plate

Structural Design Generator Face Plate Inlet Turbine Casing Coupling Casing Bolts

Generation Maxon DC Motor: Graphite Brushes -6 Volt, 3 Watt, n max =16,000 rpm -Diameter: 13mm Length: 37mm Generator Loading Faulhaber DC Motor: 1628 T012 -Brushless,  Coil winding 3 x 120° -12 Volt, 10 Watt, n max =65,000 rpm -Diameter: 16mm Length: 28mm Electrical Scope of Miniature Turbine Project

Computational Fluid Dynamics Pre-Processing –Gambit 2.0 Geometry Mesh Post-Processing –Fluent 6.0 Setup Boundary Conditions Model Solution 2D and 3D Flow Solver Equations used to solve the model: –Conservation of Mass –Conservation of Energy –Transport Equations (Navier Stokes)

Iterative Steps to Optimize Geometry

CFD Analysis of Miniature Air Turbine Torque due to forces on the blades Designing a tool to optimize future models Flow Performanc –Moving Reference Frame (MRF) –Exhaust Ports and Inlets Relocated Static Pressure Contours (Pa) Dynamic Pressure Contours (Pa)

Experimentation Fabrication Dental Turbine Experimentation to Validate Objectives and Specifications –Torque, RPM, Exit Temp., Power

Results A Miniature Turbine has been fabricated –Max Power: 18 Watts rms –Longest Continuous Run Time: 45 min. –Max Speed Achieved: 65,000 rpm –Generator Temperature: 25 °C

Results Continued

Conclusions Miniature Turbine has been fabricated. All performance specifications have been met. –Achieved three times the power needed for MAV Power to Weight Ratio of 7.3 W/N –Commercial Batteries ~ 5-10 W/N Turbine can be further scaled down to fit MAV size and power requirements