Friction Factor Measurement, Analysis, and Modeling for Flat-Plates with 12.15 mm Diameter Hole-Pattern, Tested with Air at Different Clearances, Inlet Pressures, and Pressure Ratios

Friction Factor Measurement, Analysis, and Modeling for Flat-Plates with 12.15 mm Diameter Hole-Pattern, Tested with Air at Different Clearances, Inlet Pressures, and Pressure Ratios. (December 2010) Thanesh Deva Asirvatham, B.E., Government College of Technology, Coimbatore-India Co-Chairs of Advisory Committee: Dr. Dara Childs Dr. Gerald Morrison Friction factor data are important for better prediction of leakage and rotordynamic coefficients of gas annular seals. A flat-plate test rig is used to determine friction factor of hole-pattern/honeycomb flat-plate surfaces representing annular seals. Three flat-plates, having a hole-pattern with hole diameter of 12.15 mm and hole depths of 0.9 mm, 1.9 mm, and 2.9 mm, are tested with air as the working medium. Air flow is produced between two surfaces, one having the holepattern roughness representing the hole-pattern seal and the other smooth, at the following three clearances of 0.254, 0.381, and 0.635 mm and three inlet pressures of 56, 70, and 84 bar with all possible pressure ratios at each configuration. The friction factor data are presented for all tested configurations, with description of the test rig and theory behind the calculations. The effect of hole diameter, hole depth, clearance, Reynolds number, and inlet pressure are analyzed, and friction factor models based on these parameters are calculated. Friction factor upset (an undesirable phenomenon making the test data non repeatable) is also explained.