Planar measurement of flow field parameters in nonreacting supersonic flows with laser-induced iodine fluorescence.

摘要

Planar measurements of temperature, pressure, velocity and injectant mole fraction have been conducted in cold supersonic milling flow fields using laser-induced iodine fluorescence. The measurements were conducted by seeding the flow fields with iodine, inducing fluorescence with an argon ion laser sheet, and imaging the fluorescence with a liquid nitrogen cooled CCD camera. To conduct these measurements, it was necessary to develop and verify new measurement techniques for temperature and pressure suitable for use with planar imaging. Injectant mole fraction and temperature were measured using fluorescence induced by broad band excitation. Pressure and velocity were determined from the profile and position of an absorption transition. The shape and position of the transition were measured using fluorescence resulting from narrow band excitation.;The flow fields investigated in this work are configured geometrically as SCRAMJET combustors. Both tangential and transverse injection flow fields were investigated. These measurements provide extensive maps of the thermodynamic parameters and are suitable for the validation of computational fluid dynamic codes. The measurements of injectant mole fraction are spatially complete and provide a measure of milling efficiency.