Simultaneous Measurements of Velocity, Temperature, and Pressure Using Rapid cwWavelength-Modulation Laser-Induced Fluorescence of OH

摘要

In high-speed flows, laser-induced fluorescence (LIF) on Doppler-shiftedtransitions is an attractive technique for velocity measurement. LIF velocimetry has been applied to combined single-point measurements of velocity, temperature, and pressure and two dimensional imaging of velocity and pressure. Prior to recent research using NO, LIF velocimetry in combustion related flows relied largely on the use of seed molecules. In this Letter we report simultaneous, single-point LIF measurements of velocity, temperature, and pressure using the naturally occurring combustion species OH. This experiment is an extension of earlier research in which a modified ring dye laser was used to make time resolved temperature measurements behind reflected shock waves by using OH absorption an in postflame gases by using OH LIF. A pair of fused-silica rhombs mounted on a single galvanonmeter in an intracavity-doubled Spectra-Physics 380 ring laser permit the UV output to be swept continuously over a few wave numbers at an effective frequency of 3kHz. Reprints. (js)