Demonstration of Capability of Water Flux Measurement in a Scramjet Combustor using Tunable Diode Laser Absorption Tomography and Stereoscopic PIV

Tunable Diode Laser Absorption Tomography (TDLAT) is a non-intrusive measurement technique for determining two-dimensional spatially resolved distributions of temperature and species concentration in high enthalpy flows. TDLAT combines infrared laser absorption spectroscopy with tomographic image reconstruction. The TDLAT technique has been implemented at the University of Virginia's Aerospace Research Laboratory supersonic combustion tunnel. Spatially resolved temperature and water vapor concentration measurements at the exit of the supersonic combustion tunnel have been obtained using the TDLAT technique. The tomographic reconstructions at the exit plane are presented. Water vapor concentration measurements from TDLAT are combined with velocity measurements obtained by Stereoscopic PIV to provide direct measurement of water vapor flux at the exit of the supersonic combustion tunnel. Comparison of this value to the known water vapor injected provides a demonstration of the capability of the TDLAT/SPIV technique. Such a measurement of water flux with combustion will enable combustion efficiency to be evaluated. A measurement of a high temperature non-reacting case for a water vitiation level of 12% is presented.