Radiation modelling of arbitrary two-dimensional surfaces using the surface-to-surface approach extended with a blocking algorithm

Abstract

Calculating the radiation exchange between arbitrary surfaces using view factors is a common practice in the fields of industrial furnaces, climate modelling, solar power, thermal building design and so on. Here, a new model was developed to calculate the view factors of arbitrary two-dimensional geometries. This model is based on Hottel’s crossed strings method paired with an optimized algorithm to efficiently detect shadowing effects between the surfaces. The model’s accuracy and discretization dependency was tested against an analytical view factor calculation method using an example of two concentric, infinitely extended cylinders. The model can be applied to arbitrary linear discretized two-dimensional geometries. In particular, it guarantees the highest possible accuracy within the chosen discretization. The need for developing customized view factor equations of different two-dimensional geometries is therefore no longer necessary, since the convergence of the model with decreasing mesh size on analytical results can be demonstrated. Additionally, the performance and validity of the newly developed shadowing algorithm was tested against a common brute force approach and significant speedups were achieved. Furthermore, the additional application of the net radiation method for the calculation of the heat fluxes exchanged by radiation within those geometries is shown.