Molecular Gas Radiation in the Thermal Entrance Region of a Duct

1979 ◽  
Vol 101 (3) ◽  
pp. 489-495 ◽  
Author(s):  
A. Balakrishnan ◽  
D. K. Edwards
Keyword(s):  
Wall Layer ◽  
Gas Absorption ◽  
Entrance Region ◽  
Molecular Gas ◽  
Band Model ◽  
Gas Radiation ◽  
Nusselt Numbers ◽  
Radiation Exchange ◽  
Laminar And Turbulent Flow ◽  
Transmission Factors

The effect of molecular gas radiation upon the thermal development downstream from a step change in wall temperature is examined for both laminar and turbulent flow in a black-walled flat-plate duct. The exponential-tailed band model is used to represent spectral variations in gas absorption and emission. Values of total and radiative Nusselt numbers, cold-wall-layer transmission factors, and dimensionless bulk temperatures are reported for several dimensionless axial locations and for various sets of the dimension-less controlling parameters. Even in the entrance region, self absorption by wall layer gas blocks significantly the radiation exchange between the gas core and wall. An approximate correlation is proposed for both plane-duct and pipe turbulent entrance flows.

Slab band absorptance for molecular gas radiation

1972 ◽  
Vol 12 (10) ◽  
pp. 1379-1387 ◽  
Author(s):  
D.K. Edwards ◽  
A. Balakrishnan
Keyword(s):  
Molecular Gas ◽  
Gas Radiation

Heat Transfer From Plasma in Tube Flow

1970 ◽  
Vol 92 (3) ◽  
pp. 483-489 ◽  
Author(s):  
P. S. Schmidt ◽  
G. Leppert
Keyword(s):  
Heat Transfer ◽  
Finite Difference ◽  
Plasma Flow ◽  
Reynolds Numbers ◽  
Entrance Region ◽  
Constant Property ◽  
Heavy Particles ◽  
Nusselt Numbers ◽  
Mixed Mean ◽  
Temperature Constant

Heat transfer data are reported for partially ionized argon flowing in a water-cooled circular tube, 1/2 in. in dia. Experiments were run with initial mixed-mean temperatures up to 21,000 deg R at Reynolds numbers from 140–527 based on equilibrium properties evaluated at the entrance mixed-mean temperature. Measured plasma flow Nusselt numbers computed on an enthalpy basis correlate well with low temperature, constant property results after the first 5–10 diameters of the tube entrance region; closer to the entrance, Nusselt numbers were about 30 percent higher than constant property entrance region predictions. The tendency of the data to approach the constant property solution rapidly was predicted by a laminar finite-difference analysis for plasma flow published earlier [1]. The analysis was modified for the present study to improve its accuracy. The finite-difference theory under predicts the heat transfer in the first few tube diameters; two possible reasons for this discrepancy are the poor resolution in the inlet enthalpy profiles near the tube wall and nonequilibrium between electrons and heavy particles in this region.

Molecular Gas Band Radiation in Cylinders

1974 ◽  
Vol 96 (1) ◽  
pp. 21-26 ◽  
Author(s):  
A. T. Wassel ◽  
D. K. Edwards
Keyword(s):  
Heat Flux ◽  
Spherical Symmetry ◽  
Radiative Heat ◽  
Band Head ◽  
Molecular Gas ◽  
Band Model ◽  
Beam Length ◽  
Transfer Problems ◽  
Gas Volume ◽  
Axial Band

The radiative heat flux in a molecular gas within a cylinder is formulated in terms of an axial band absorptance. The axial band absorptance function is used to reduce the two angular, one spatial, and one spectral integrals encountered to one angular and one spatial integral such as is encountered in radiative transfer problems with spherical symmetry. A closed form is obtained for the axial band absorptance for the exponential-winged band model. Illustrative results are presented for a cylindrical gas volume with trapezoidal, parabolic, or Gaussian temperature profile. Mean beam length, absorptivity, and emissivity of a cylinder of gas are obtained as a function of the optical depth at the band head.

scholarly journals The libRadtran software package for radiative transfer calculations (Version 2.0)

2015 ◽  
Vol 8 (12) ◽  
pp. 10237-10303 ◽  
Author(s):  
C. Emde ◽  
R. Buras-Schnell ◽  
A. Kylling ◽  
B. Mayer ◽  
J. Gasteiger ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Radiative Transfer ◽  
Software Package ◽  
Radiative Forcing ◽  
Gas Absorption ◽  
Molecular Gas ◽  
Photolysis Frequencies ◽  
Aerosol Scattering ◽  
Version 2.0 ◽  
Climate Studies

Abstract. libRadtran is a widely used software package for radiative transfer calculations. It allows to compute (polarized) radiances, irradiances, and actinic fluxes in the solar and thermal spectral regions. libRadtran has been used for various applications, including remote sensing of clouds, aerosols and trace gases in the Earth's atmosphere, climate studies, e.g., for the calculation of radiative forcing due to different atmospheric components, for UV-forcasting, the calculation of photolysis frequencies, and for remote sensing of other planets in our solar system. The package has been described in Mayer and Kylling (2005).. Since then several new features have been included, for example polarization, Raman scattering, a new molecular gas absorption parameterization, and several new cloud and aerosol scattering parameterizations. Furthermore a graphical user interface is now available which greatly simplifies the usage of the model, especially for new users. This paper gives an overview of libRadtran version 2.0 with focus on new features. A complete description of libRadtran and all its input options is given in the user manual included in the libRadtran software package, which is freely available at http://www.libradtran.org.

Analysis of Molecular Gas Radiation: Real Gas Property Effects

1999 ◽  
Vol 13 (4) ◽  
pp. 460-466 ◽  
Author(s):  
K. C. Tang ◽  
M. Q. Brewster
Keyword(s):  
Molecular Gas ◽  
Real Gas ◽  
Gas Radiation
Sign in / Sign up

Export Citation Format

Share Document