BS in Mechanical Engineering
Mechanical Engineering Department
The boundary layer data system (BLDS) is the result of a collaborative effort between Dr. Westphal, a researcher and instructor at Cal Poly, and Northrop Grumman. The BLDS is capable of measuring the boundary layer profile and characteristics of flow over aerodynamic surfaces and is intended for high altitude, high speed use. The instruments inside the BLDS malfunction at the low temperatures present when operating in flight at altitudes above 30,000 ft.
To solve this problem, analysis was done on the existing BLDS which determined the heating requirements, around 50 watts, needed to keep the internal temperature within the rated operating range for the electronic components. Different methods to provide heat were investigated and it was decided that the design would be a ducted axial turbine similar to a micro-ram air turbine (micro-RAT). This design was chosen due to the high potential for efficiency while reducing the weight and size of the turbine. The micro-RAT was designed around a high efficiency generator which was put through testing before the design was complete. The generator testing showed it was capable of producing 350 watts, seven times the specified requirements. A second test was also performed during the design phase to prove the concept of an axial turbine. A model airplane rotor was attached to the generator and run in the wind tunnel. The test was ended before a maximum output could be reached but the data collected proved the generator could perform at high speed and enough power was available in the wind to meet the design requirement. To design the rotor geometry, all parts were made in a rapid prototype machine and two sets of fifteen rotors were created, each with different adjustments made to the pitch, chord, and number of blades. The rotors were tested in the wind tunnel and the rotor with the best performance (projected power generation of 65W at operating conditions) was selected. The final design was then cast in Inconel 718.
The following report explains the entire design process in detail. It describes and defends the analysis methods chosen and explains the testing procedures and results.