e_H2O

This script calculates standard emissivity, total emissivity and pressure correction for H2O mixtures with nitrogen or air.

Excel-script included in the downloadable package.

This script calculates standard emissivity, total emissivity and pressure correction for H2O mixtures with nitrogen or air. Pressure correction is calculated as total emissivity divided by standard emissivity. Both standard and total emissivities have been calculated using the HITEMP-2010 database.

Valid range:

• T ≥ 450 K and T ≤ 3000 K
• p_L ≥ 0.01 bar * cm and p_L ≤ 3000 bar * cm
• p_E ≥ 0.05 bar and p_E ≤ 250 bar

This script extrapolates the emissivity if you go above or below these boundaries but these results are not reliable after certain point.

Example:

e = e_H2O(T, x_H2O, L, p_total, Output)

e = e_H2O(1000, 0.17, 100, 2, 'Standard')

Variables:

• T is temperature in K
• x_H2O is the mole fraction of H2O gas component in a gas mixture
• L is the length in cm
• p_total is total pressure of a gas mixture in bar
• p_L is the pathlength in bar * cm
• p_E is the equivalent pressure in bar
• Output can be either 'Standard', 'Total' or 'Correction'.

Reference:

M. Alberti, R. Weber, M. Mancini. 2016. Re-creating Hottel's emissivity charts for water vapor and extending them to 40 bar pressure using HITEMP-2010 data base. Combustion and Flame, Vol 169, 2016, pages 141-153.