Spontaneous Ignition of Hydrothermal Flames in Supercritical Ethanol Water SolutionsResults are reported from recent tests where hydrothermal flames spontaneously ignited in a Supercritical Water Oxidation (SCWO) Test Cell. Hydrothermal flames are generally categorized as flames that occur when appropriate concentrations of fuel and oxidizer are present in supercritical water (SCW); i.e., water at conditions above its critical point (218 atm and 374 C). A co-flow injector was used to inject fuel, comprising an aqueous solution of 30-vol to 50-vol ethanol, and air into a reactor held at constant pressure and filled with supercritical water at approximately 240 atm and 425 C. Hydrothermal flames auto-ignited and quickly stabilized as either laminar or turbulent diffusion flames, depending on the injection velocities and test cell conditions. Two orthogonal views, one of which provided a backlit shadowgraphic image, provided visual observations. Optical emission measurements of the steady state flame were made over a spectral range spanning the ultraviolet (UV) to the near infrared (NIR) using a high-resolution, high-dynamic-range spectrometer. Depending on the fuel air flow ratios varying degrees of sooting were observed and are qualitatively compared using light absorption comparisons from backlit images.
Document ID
20170006847
Acquisition Source
Glenn Research Center
Document Type
Conference Paper
Authors
Hicks, Michael C. (NASA Glenn Research Center Cleveland, OH United States)
Hegde, Uday G. (Case Western Reserve Univ. Cleveland, OH, United States)
Kojima, Jun J. (Ohio Aerospace Inst. Cleveland, OH, United States)
Date Acquired
July 19, 2017
Publication Date
April 23, 2017
Subject Category
Chemistry And Materials (General)Inorganic, Organic And Physical Chemistry