Stanford
Hanson Research Group

Hypersonic Ground Testing

testing equipment and a digital rendering of the shape

The Hypersonic AeroPropulsion Clean Air Testbed (HAPCAT) facility is a state-of-the-art propulsion facility crucial to testing and evaluating next-generation hypersonic vehicles [1].

The HAPCAT facility (located at the Arnolds Air Force Base) provides variable flow velocities up to Mach 8 through a convergent-divergent nozzle, requiring temperatures up to 2500 K upstream of the nozzle throat. These temperatures, which must be measured to ensure correct operating conditions, are hot enough to melt conventional thermocouples. The Hanson Research Group is developing non-intrusive temperature measurements via laser absorption thermometry for nitric oxide (NO), a common chemical species which naturally forms in high-temperature air. This accurate temperature characterization is vital for proper facility operation and directly informs the operation of a sensor recently installed into the HAPCAT [2].

two graphs showing accuracy of heat measurement
Demonstration of the accuracy of two-line NO thermometry method across temperatures characteristic to the HAPCAT facility [2].

To learn more, check out some of our publications:

[1] T. P. Fetterhoff and J. W. Burfitt, “Overview of the Advanced Propulsion Test Technology Hypersonic Aero Propulsion Clean Air Testbed,” 17th AIAA International Space Planes and Hypersonic System and Technologies Conference (2012) p. 2279. DOI: 10.2514/6.2011-2279

[2] C. A. Almodovar, R. M. Spearrin, and R. K. Hanson, “Two-color laser absorption near 5 μm for temperature and nitric oxide sensing in high-temperature gases,” Journal of Quantitative Spectroscopy and Radiative Transfer, Vol. 203 (2017) pp. 572–581. DOI: 10.1016/j.jqsrt.2017.03.003

[3] C. A. Almodovar, W-W. Su, C. L. Strand, and R. K. Hanson, “R-branch line intensities and temperature-dependent line broadening and shift coefficients of the nitric oxide fundamental rovibrational band,” Journal of Quantitative Spectroscopy and Radiative Transfer, Vol. 239 (2019) 106612. DOI: 10.1016/j.jqsrt.2019.106612

[4] C. A. Almodovar, W.-W. Su, R. Choudhary, J. K. Shao, C. L. Strand, and R. K. Hanson, “Line mixing in the nitric oxide R-branch near 5.2 μm at high pressures and temperatures: Measurements and empirical modeling using energy gap fitting,” Journal of Quantitative Spectroscopy and Radiative Transfer, Vol. 276 (2021) 107935. DOI: 10.1016/j.jqsrt.2021.107935

[5] Su, W.-W., Boulet, C., Almodovar, C. A., Ding, Y., Strand, C. L., and Hanson, R. K., “Line mixing study on the fundamental rovibrational band of nitric oxide near 5.3 μm,” Journal of Quantitative Spectroscopy and Radiative Transfer, vol. 278, Feb. 2022, p. 107997