- Author
- Manohar, S. S. | Kulkarni, A. K. | Thynell, S. T.
- Title
- In-Depth Radiation Properties of PMMA Before and After Surface Pyrolysis.
- Coporate
- Pennsylvania State Univ., University Park
- Sponsor
- National Institute of Standards and Technology, Gaithersburg, MD
- Contract
- NIST-GRANT-60NANB8D0849
- Book or Conf
- Combustion Institute/Eastern Section. Chemical and Physical Processes in Combustion. Proceedings. Fall Technical Meeting, 1991. October 14-16, 1991, Ithaca, NY, 95/1-4 p., 1991
- Keywords
- combustion | polymethyl methacrylate | pyrolysis | data analysis | slabs (members)
- Identifiers
- transmittance measurements; absorption coefficients
- Abstract
- The absorption coefficient (alternatively expressed as the in-depth absorption length) is important in assessing the in-depth radiation absorption effects. In particular, it is an essential input to a mathematical model that attempts to predict upward flame spread subjected to strong external radiation. Such cases are frequently encountered in real fire situations, for example, in confined spaces where burning surrounding walls constitute a source of radiant energy. Plstics such as polymethylmethacrylate (PMMA) can absorb external radiation to a significant degree, and it depends on the spectral characteristics of incoming radiation during the heat up time. After surface pyrolysis, the transmittance of PMMA samples is very low since the surface is rough, with trapped bubbles, and soot contamination. Very little quantitative information is available on this property for most practical materials. Recently, we have started experiments for the determination of radiative properties of real materials. The objective of this paper is to present transmittance measurements for PMMA slabs, before and after surface pyrolysis, and the calculated spectral and mean absorption coefficients.