Development and Application of an Advanced Optical Based Pressure Instrument for Low-Speed Flows

摘要

The STTR Phase I program targeted the development and application of advanced optical based systems the determination of surface-pressure distributions on test models in the Subsonic Aerodynamic Research Laboratory (SARL) at Wright Laboratory. The low-speed flows (0.1 less than or equal M less than or equal 0.5) encountered in the SARL facility effect relatively small changes in surface pressure, typically 1-2 psi about ambient (14.7 psia). As a result, quantitative surface-pressure determination in this environment remained contingent on the development of innovative pressure-sensitive paint (PSP)- coating and optical-measurement technology possessing the requisite sensitivity characteristics. The technical effort encompasses three primary objectives-the development of advanced PSP systems, data-acquisition instrumentation and measurement techniques, and post-processing software. In the Phase I effort, we have coupled the tools of sol-gel-processing technology and inorganic synthetic chemistry for the development of stable PSP's exhibiting tunable performance characteristics. Phase I research has produced sol-gel-based PSP's exhibiting significant improvements in sensitivity about ambient pressure, reduced temperature sensitivity (80%), and fast (>1 kHz) temporal response. Non- intrusive, optical-based measurement techniques capable of accurate pressure measurements in low-speed wind tunnels will find immediate application in commercial- and military-aircraft, automotive, and architectural industries in the United States.