High-Speed, Two-Dimensional Sensor Suite for Fuel-Air Ratio and Heat-Release Rate for Combustor/Augmentor Stability

ABSTRACT:The goal of the proposed effort will be to demonstrate a diagnostic technique that can simultaneously measure the combustion progress variable, the flow velocity, and the fuel-to-air ratio with high spatial and temporal resolution to allow the local heat release to be determined. This approach will require the combination of two well-established diagnostic techniques laser induced breakdown spectroscopy (LIBS) and laser acoustic anemometry (LAA). The former method will be utilized to measure local FARs, and the latter method will be employed to measure the speed of sound from which the local gas temperature and velocity can be determined. Once the local FAR, temperature, and velocity are known, the local heat release can be determined from thermodynamic principles. To accomplish this objective the following Phase I tasks are being proposed: Task 1. Construct and Calibrate LIBS System Task 2. Construct and Calibrate LAA System. Task 3. Construct Combined LIBS/LAA System. Task 4. Conduct Demonstration Tests in Large-Scale Atmospheric Burner. Task 5. Make Recommendations for Phase II System BENEFIT:The simultaneous measurement of FAR, temperature, velocity, and heat release is a significant step forward for the study of real-world combustors. The utilization of LIBS to measure combustion FAR has many commercial applications from automotive to industrial furnaces. The addition of the LAA system greatly increases the range of measurement capability and the usefulness of the experimental data. For example, combustion modeling typical utilized mixture fraction to determine flame characteristics (temperature, species, and pollutant formation) however, what they can only guess at is the local reaction progress variable. LIBS allows measurements of FAR but not the progress variable which requires in this case a simultaneous temperature measurement. The combined LIBS/LAA instrument provides both numerical and experimental combustor designers an important experimental tool that provides key experimental data for computational model evaluation.