Calculation of radiation heat transfer view factors among fuel rod bundles based on CFD method

• An ideal to calculate the view factor within nonstandard assemblies is proposed.
• The discrete transfer model based on CFD method is validated by theoretical formulas.
• The discrete transfer model can be well suitable for non-square assemblies.

The view factor has a great influence on the radiation heat transfer. Existing theoretical formulas about the view factors among fuel rod bundles are only suitable for the square assemblies. For non-standard bundle assembly structure, such as the circular and hexagonal bundle assemblies, the view factors cannot be calculated by the theoretical formulas. Aiming at the problem, two different radiation heat transfer models, which are discrete transfer model (DTRM) and discrete ordinates model (DO), are proposed based on the CFD method and validated by the theoretical formulas under the condition of square assembly. The results show that the DTRM can accurately and reliably calculate the view factor among the rods in square bundle. Taking into account the similarity in the radiation heat transfer among the rods in homotopy bundle assembly structures, the DTRM model can be used for the calculation of view factor in other non-standard fuel rod bundle assembly.