The Raman Code automates the analysis of laser-Raman- spectroscopy data for diagnosis of combustion at high pressure. On the basis of the theory of molecular spectroscopy, the software calculates the rovibrational and pure rotational Raman spectra of H2, O2, N2, and H2O in hydrogen/air flames at given temperatures and pressures. Given a set of Raman spectral data from measurements on a given flame and results from the aforementioned calculations, the software calculates the thermodynamic temperature and number densities of the aforementioned species. The software accounts for collisional spectral-linebroadening effects at pressures up to 60 bar (6 MPa). The line-broadening effects increase with pressure and thereby complicate the analysis. The software also corrects for spectral interference ("crosstalk") among the various chemical species. In the absence of such correction, the cross-talk is a significant source of error in temperatures and number densities. This is the first known comprehensive computer code that, when used in conjunction with a spectral calibration database, can process Raman-scattering spectral data from high-pressure hydrogen/ air flames to obtain temperatures accurate to within ±10 K and chemicalspecies number densities accurate to within ±2 percent.

This work was done by Quang-Viet Nguyen of Glenn Research Center and Jun Kojima of the National Research Council. For further information, access the Technical Support Package (TSP) free on-line at www.techbriefs.com/tsp under the Software category.

Inquiries concerning rights for the commercial use of this invention should be addressed to

NASA Glenn Research Center
Innovative Partnerships Office
Attn: Steve Fedor
Mail Stop 4–8
21000 Brookpark Road
Cleveland
Ohio 44135.

Refer to LEW-17769-1.


NASA Tech Briefs Magazine

This article first appeared in the February, 2006 issue of NASA Tech Briefs Magazine.

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