Complete three-dimensional multiparameter mapping of a supersonic ramp fuel injector flowfield

Abstract

Planar laser-induced iodine fluorescence is used to map out the nonreacting mixing flowfield of an unswept ramp fuel injector using air injected at Mach 2.0 into a Mach 2.9 freestream. A fully automated test setup is used to measure time-averaged pressure, temperature, velocity, and injectant mole fraction on 21 crossflow planes and 7 axial planes. The measurement uncertainties are 5-8% for temperature, 4-10% for pressure, 10-20 m/s for velocity, and 2-3% for injectant mole fraction depending on the thermodynamic conditions. The measurements allow any desired gasdynamic quantity to be determined on a three-dimensional grid that spans the entire wind-tunnel test section. The experimental data set is comparable to the completeness of results normally available only from a computational fluid dynamics simulation. Results showing detailed flow features on specific planes, as well as overall quantities, such as global conservation checks, mixing performance, and flowfield losses, are presented. Mass, momentum, and energy flux, determined at the crossflow plane locations of the data set, show about a 2% standard deviation. The results are compared to a simulation using a three-dimensional Navier-Stokes solver. Agreement is reasonable with the exception of measurements in regions very close to walls, where the intensity of scattered light is high or where optical access is limited. The ability to generate extensive data sets, such as the one presented here, demonstrates that the planar laser-induced iodine fluorescence technique can be used 1) to generate detailed test cases for the validation of computational fluid dynamics codes and 2) as an alternative to computational fluid dynamics for performing design studies and performance evaluation in complex compressible flows.