COMPUTER-CONTROLLED MULTIPARAMETER FLOWFIELD MEASUREMENTS USING PLANAR LASER-INDUCED IODINE FLUORESCENCE

A measurement technique for the mapping of complex compressible flowfi elds using planar laser-induced iodine fluorescence (PLIIF) is present ed. Time-averaged values of all relevant flowfield properties are foun d: pressure, temperature, velocity, and, for mixing flowfields, inject ant mole fraction. Several modifications have been made to a previous version of the PLIIF technique that allow multiple planes of data, nee ded for studying highly three-dimensional flowfields, to be collected and processed in greatly reduced time and with improved measurement ac curacies. The technique is demonstrated with measurements in the flowf ield of a Mach 2, rearward-facing step. Detailed comparisons are made to a computational fluid dynamics simulation of the flowfield. Differe nces between measured and simulated temperatures in the step recircula tion region decreased from 21 to 4 %, compared with previous broadband planar temperature measurements. Measurement accuracies are strong fu nctions of the thermodynamic conditions. For the conditions seen in th e step flowfield studied, estimated uncertainties range from 5-8% for temperature, 4-12% for pressure, 10-20 m/s for velocity, and 2-3% for injectant mole fraction. In regions very close to walls errors may be larger because of scattered laser light. The technique presented repre sents a unique tool that allows complex, compressible, three-dimension al flowfields to be mapped out completely and nonintrusively.