Interpretation of a turbulent radiating gas as a lowPrandtlnumber fluid
Abstract
A problem to analysts treating simultaneous thermal radiation and turbulent convection in nongray combustion gases is whether or not radiation affects the eddy diffusivity for heat. It is argued that the question can be answered approximately by considering turbulent radiating gas eddies to be eddies of a nonradiating fluid of low Prandtl number and taking the eddy diffusivity for heat accordingly. A relation for the effective low Prandtl number of a nongray gas is derived. When the argument showing that a radiating gas behaves like a low Prandtl number fluid is completed, it is further argued that, as a consequence, a low Prandtlnumber heat transfer correlation can be used approximately with an effective Prandtl number scaled to the size of the conduit rather than to the size of the eddies.
 Publication:

Letters Heat Mass Transfer
 Pub Date:
 August 1974
 Bibcode:
 1974LHMT....1...19E
 Keywords:

 Combustion Physics;
 Convective Heat Transfer;
 Nongray Gas;
 Prandtl Number;
 Thermal Radiation;
 Turbulent Diffusion;
 Wall Temperature;
 Combustion Chambers;
 Gas Dynamics;
 Numerical Analysis;
 Pipe Flow;
 Radiative Heat Transfer;
 Turbulent Heat Transfer;
 Fluid Mechanics and Heat Transfer