1. Implementation of Vortex Cavities in a Turbojet Diffuser Sponsor: Williams International Progress Report 1 October 26, 2006 TEAM CRUISE CONTROL Michael Feldman Marvin Kong Nansi Xue

2. Objective Williams International intends to reduce diffuser length Shorten diffuser length by at least 1 inch Optimize diffuser efficiency by preventing or delaying separation

3. Proposed Solution Implement annular vortex cavities to delay flow separation Cavity positioned at point of separation Flow encounters cavity and local vortex flow develops Feedback from cavity to inlet creates suction effect Downstream boundary layer is thinned and separation is minimized.

4. Current Design Feedback to inlet to be achieved via system of tubing Measurement of feedback flow One feedback tube will be connected to Pitot-static probe. Position of vortex cavity to be determined after CFD Analysis

5. Baseline Models Two baseline models: Regular Length and Shortened (by 1.5 inch) Regular length model results will be our standard to benchmark against Flow-path of the regular length model from previous group may not allow separation. (Designed using Powell’s Matlab code) We will test to determine whether separation occurs. Shortened model will have flow separation. We will test our cavity design based upon this shortened model to see if we can meet or surpass our regular-length benchmark.

6. Diffuser with Prescribed Blockage CL 4.7” 3.11” R 1.2” R ¼ Ellipse.208” Blockage, 5 per 360° Ellipse Ratio should be 1.5.97” 1.543” R 2.625” R 1.0” min INLET MACH NUMBER = 0.4

7. Outside Assitance Contacted: Professor Kenneth G. Powell member of the W. M. Keck Foundation Computational Fluid Dynamics Laboratory co-founder and co-director of the Center for Space Environment Modeling Will assist by providing CFD assistance and Matlab code for calculating the optimal diffuser flow path of the reduced length diffuser. CFD Model will provide crucial data for the positioning of the Vortex Cavity

8. Budget Changes Budget decreased by approximately $50. We will save money by reusing the mounting interface from the previous 405 team. Previous Group’s Setup

9. Test Plan Workshop Day 1: Modify regular-length diffuser (cut out blockage) Modify shortened diffuser (holes for measurement probes) Wind Tunnel Test Day 1: Test unmodified regular-length diffuser Test unmodified shortened diffuser Data Analysis Wind Tunnel Test Day 2: Test shorted diffuser with implemented vortex cavity Data Analysis Comparison to Original to view affects of vortex cavities

10. Questions?