Below are items from the 44th DCASS, held 8 March 2019.
The X-Ray Glasses You Always Wanted
Brian Bohan and Greg Cobb
Air Force Institute of Technology
The JetCat P160 RXi small turbojet engine was CT scanned to identify the placement of the internal components as shown above. This engine was planned to be used as a demonstration engine for a turbomachinery class. Additional pressure and temperature instrumentation were added to allow the students to calculate performance values at a number of throttle settings. The CT scanner was used to visualize and measure the proper places to drill through the outer casing to install the instrumentation without requiring engine disassembly.
Play the Alumina Pipe Organ
Megan Harkins
Air Force Institute of Technology
This figure captures the interior of a diamond-drilled hole in an oxide-oxide composite (N720TM/alumina) that was tested in tensile creep at 1200 C. The objective of this effort was to assess how the presence of diamond-drilled holes affected the mechanical behavior of the composite. Post-test micrographs were used to characterize the composite microstructure in the vicinity of the holes, and helped identify factors that contributed to the degraded properties.
Periwinkle Flower of Flame
Brian Bohan, Tylor Rathsack, and Marc Polanka
Air Force Institute of Technology
This photo shows visible emissions from the CH radical of propane combustion exiting the six bladed hybrid guide vane array in a centrifugally loaded Ultra-Compact Combustor. With a significantly shorter axial length, the Ultra-Compact Combustor is a space-saving potential replacement to a traditional axial combustor in gas turbine engines. The passages between the hybrid guide vanes serve as a secondary combustion zone in addition to serving as a stator vane and turning the engine core flow to the desired turbine rotor inlet flow angle. There is no rotor in the current experiment.
Starry Flight
Aditya Deshpande, James Wells, Manish Kumar, and Ali Minai
University of Cincinnati
The video from the quadcopter can be processed for object classification using Deep Learning networks. We used the features of an input image from video at intermediate layers of Neural Network (VGG-19) optimized for object classification and combined it with features of intermediate layers of the same network with input image of the painting "The Starry Night by Vincent van Gogh", using the Neural Algorithm of Artistic Style Transfer by Gatys et. al (2016). This approach can be used to create artistic images using the scenic videos captured from the drone camera.
The Ring of Fire
Tylor Rathsack
Air Force Institute of Technology
This video shows combustion inside the circumferential cavity of an Ultra Compact Combustor. Twelve backwards facing steps along the outside diameter of the cavity are used to stabilize the flame and a hybrid guide vane (round component in center of video) alters the exit flow angle and houses secondary reactions.
Up in Flames: Burning in a (Centrifugal) Gravity Well
Timothy Erdmann
Innovative Scientific Solutions, Inc.
Schlieren videos of turbulent premixed propane-air flames at phi = 1.1 are shown being accelerated toward the centroid of curvature as it flows around a curved channel with a square cross-section. This buoyant action is caused by centrifugal forces acting on the density gradient across the flame (Rayleigh-Taylor instability). Eight videos in this mosaic are shown at various inlet velocities and resultant centrifugal g-loads (v^2/rg): (starting at the top right of the largest full circle and going clockwise) 4 m/s [30 g's], 8 m/s [120 g's], 16 m/s [480 g's], 24 m/s [1,000 g's], 32 m/s [1,800 g's], 40 m/s [2,800 g's], 44 m/s [3,400 g's], 48 m/s [4,100 g's]. Videos were captured with a Phantom v12 camera at 20 kHz frame rate and 4 μ s exposure time. Image resolution is 85 μm/pixel. 88ABW-2018-6449