Conversion Factors among Smoke Measurements

A set of smoke measurement conversion equations are derived. The equations convert any of eleven smoke measurements to the other ten measurements. The eleven measurements are: Bosch, SAE, and ASTM (Bacharach) smoke numbers, Hartridge opacity, PHS opacity, Calesco model C107 opacity, extinction coefficient, transmittance, opacity, fraction of fuel carbons converted to smoke, and mass fraction of smoke in the exhaust gas. These eleven smoke measurement methods are described along with a general explanation of the consonance of smoke measurement methods, which allows one to derive equations for interconverting them. A FORTRAN program is listed which performs the conversions. The predictions of the program are shown to be within the scatter of published experimental data. However, published experimental data varies by as much as a factor of two. The conversion equations enable experimenters to choose a smoke measurement method which is sensitive to expected smoke concentrations.