Natural icing conditions and data analysis for engine testing: boeing engine testing used during the 777-200/ 737-700 certification programs

摘要

During the 777-200 certification test program,specific testing was required to demonstrate engine operation in natural icing conditions.This paper presents typical natural icing conditions encountered during the 777-200 and 727-700 flight test programs,including flight conditions,engine conditions,and analysis procedures.The analysis procedures presented are primarily for onboard real-time analysis to verify icing conditions.Two different methods of determining droplet size were used during these programs.The 737-700 program used an AeroMetrics Laser Phased Doppler Particle Analysis (PDPA) Probe,which acquired droplet size near real-time during natural ice testing.The 777-200 program used a droplet snatcher,which determined droplet size via post test analysis.This paper also includes a brief account of the problems encountered and the instrumentation used to quantify the natural icing conditions.