Correction factor emissivity, gases

Water Vapor The contribution to the emissivity of a gas containing H9O depends on Tc andp L and on total pressure P and partial pressure p . Table 5-8 gives constants for use in evaluating . Allowance for departure from the special pressure conditions is made by multiplying by a correction factor C read from Fig. 5-21 as a function of (p + P) and p ,L. The absorptivity 0t of water vapor for blackbody radiation is evaluated from Table 5-8 but at T instead of Tc and at p LT /Tc instead of p, h. Multiply by (Tc/Ti)° . ... 

Use of the optically thin value of the mean beam length yields values of gas emissivities or exchange areas that are too high. It is thus necessary to introduce a dimensionless constant P < 1 and define some new average mean beam length such that KLm = P mo-For the case of parallel plates, we now require that the mean beam length exactly predict the gas emissivity for a third value of KL. In this example we find p = -An[2Es(KL)]/2KL and for KL = 0.193095 there results p = 0.880. The value p = 0.880 is not wholly arbitrary. It also happens to minimize the error defined by the so-called shape correction factor ( ) = [9(.s /dAi]/ l - for all KL > 0. The... 

Emissivity tg is therefore the ratio of the rate of energy transfer from the gas to the surface element to the rate of transfer from a black hemispherical surface of radius L and temperature Tg to the same surface element. Figure 14.11 shows how Eg for carbon dioxide varies with radius L and partial pressure pg. Figure 14.11 applies at a total pressure p of 1 atm Fig. 14,12 gives the correction factor for finding Eg at other total pressures. 

Gas analysis for the determination of emission rate correction factor or excess air Determination of carbon dioxide, methane, nitrogen, and oxygen from stationary sources Determination of moisture content in stack gases Determination of particulate matter emissions from stationary sources... 

The related theory about extenics is founded by the Chinese scholars Cai wen to solve the problem of subjective and objective contradictions in 1983 (Cai, 1983), it bases on the matter-element theory and extension set theory and does research on the influence degree of the described problems about quantity and quality , so as to completely know the system features (Guo et al., 2009). Due to the complexity production conditions of underground working face, there are a variety of factors that affect gas emission, how to quickly and accurately judge the reasons that why the gas emission is abnormal is an important task of gas early-warning, the extension theory can calculate the abnormal gas emission level by using the normalized correlation function. Under the condition of correct identification of gas hazard in coal mine. 

If the bounding surface is gray rather than black, multiplication of Eq. (5-154) by surface emissivity 1 allows properly for reduction of the primary beams, gas-to-surface or surface-to-gas, but secondary reflections are ignored. The correction then lies between 1 and 1, and for most industrially important surfaces with 1 > 0.8 a value of (1 -t- 1)/ 2 is adequate. Rigorous allowance for this and other factors is presented later, e.g., Eq. (5-163). 

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