Page 245 - Mechanical Engineers' Handbook (Volume 4)

234 Furnaces

Figure 15 Radiation view factors for parallel planes. 1

dioxide and water vapor. Published data on emissivities of these gases show intensity of
radiation as a function of temperature, partial pressure, and beam length. The combined
emissivity for mixtures of carbon dioxide and water vapor requires a correction factor for
mutual absorption. To expedite calculations, a chart has been prepared for the overall em-
issivity of some typical flue gases, including these correction factors. The chart in Fig. 20
has been calculated for products of combustion of methane with 110% of net air demand,
and is approximately correct for other hydrocarbon fuels of high heating value, including

Figure 16 Radiation view factors for perpendicular planes. 1