Development of a Tomography Technique for Application to a Scramjet Wind Tunnel

A tunable diode laser absorption tomography (TDLAT) technique is being developed at the University of Virginia to determine the spatially-resolved distribution of temperature and water vapor concentration in a scramjet combustor. In order to aid in the development of this technique, the present study simulates integrated line-of-sight projection measurements and reconstructs these projections to determine the effects of data collection geometry and ambient water vapor on reconstruction accuracy. Results show that reconstruction error is more dependent on the number of rays taken in each projection than on the number of projections taken around the periphery of the flow. Additionally, reconstruction error appears to be linearly dependent on the amount of ambient water vapor that is external to the region of interest in the spectroscopic measurements. Overall, these results show that TDLAT data collection time can be reduced by taking fewer projections with a high density of rays while maintaining reconstruction accuracy.