The finite-volume method has been shown to effectively predict radiant exchange in geometrically simple enclosures where the medium is gray, absorbing, emitting, and scattering. Cartesian and circular cylindrical meshes have always been used. The present article shows that the method applies equally well to geometrically complex enclosures where nonorthogonal, boundary-fitted meshes are used. This development permits radiant heat transfer to be computed on the same mesh employed to solve the equations of fluid motion.

Computation of radiant heat transfer on a nonorthogonal mesh using the finite-volume method

Radiation heat transfer in combustion systems

Effects of radiation model on the modeling of a laminar coflow methane/air diffusion flame

The finite-volume method is extended to compute radiation in axisymmetric geometries using unstructured polyhedral meshes. Control angle overhangs, resulting from the nonalignment of the angular discretization with cell faces, are accounted for in the differencing. Conservative discretization of the angular redistribution term is proposed, and allows the solution of axisymmetric problems on the same two-dimensional mesh as the fluid flow. The method is shown to be equivalent to the mapping procedure of Chui and Railhby. The scheme is applied to a number of benchmark problems and is shown to perform satisfactorily.

Radiative heat transfer in axisymmetric geometries using an unstructured finite-volume method

An unstructured finite volume method for radiative heat transfer has been developed and they are applicable for any 2D planar, axisymmetric, or 3D problems with structured, unstructured, or hybrid grids. The angular domain is discretized by either the Sn-type discretization strategy or the azimuthal discretization strategy. For a 2D axisymmetric problem, the artifice developed by Carlson and Lathrop has been employed to treat the angular derivative terms, and a general formulation for the curvature coefficients of angular redistribution α m ±1/2 has been subsequently developed. In order to validate the developed unstructured method, six benchmark problems with a wide range of conditions have been examined. The grids considered for each problem include a structured grid and an unstructured grid. The solutions based on the present unstructured method are very close for structured and unstructured grids and they all have a very good agreement with available other solutions. The present study indicates that not only is the developed unstructured radiation model flexible in treating problems with complicated geometries but also it is very accurate and efficient.

Shyam S. Dua

Papers

Multi-dimensional radiative transfer in non-isothermal cylindrical media with non-isothermal bounding walls

Exact solutions for multi-dimensional radiative transfer in non-isothermal spherical media