Computation of view factors for surfaces of complex shape including screening effects and using a boundary element approximation
Purpose - This paper describes an approach for the automatic calculation of view factors between surfaces of arbitrary shape, when taking into account possible screening effects due to intermediate surfaces. Design/methodology/approach - The specifically developed numerical code is based on the utilization of boundary elements to fit the surfaces of an algorithm solving the shadow effect and on a Monte Carlo method for the numerical integrations. Findings - The code has been tested for a set of geometrical configurations. It was clearly shown that it obtains good results in terms of accuracy and computing time. Its accuracy increases when the mesh of radiative surfaces is finer. Research limitations/implications - The use of the code is limited to opaque surfaces separated by an isothermal semi-transparent medium which can be absorbent but not diffusing of the thermal radiation. Practical implications - The study of the radiative exchanges between opaque surfaces with shadow effects due to intermediate surfaces may have concrete practical applications by using this code. Indeed, the code has been used for an industrial application, in order to evaluate view factors inside an enclosure, in the framework of studies concerned with the thermal comfort inside cars. Originality/value - The originality of this paper lies in taking into account the surfaces of complex geometries by using a boundary elements approximation, the algorithm solving the shadow effect, based on the convexity of the quadrilateral in 2D or the polyhedron in 3D.
heat transfer boundary-elements methods monte carlo simulation thermal conductivity