The discussion centers on the calculation of pressure drop in fuel assemblies, specifically in the context of pressurized water reactors (PWR) and boiling water reactors (BWR). Participants explore various aspects of fluid dynamics related to fuel assemblies, including friction factors, pressure drop calculations, and the significance of specific coefficients in these calculations.
Participants generally agree on the complexity of calculating pressure drops in fuel assemblies and the importance of specifying the type of reactor flow. However, there are multiple competing views regarding the methodologies and significance of various parameters in these calculations, and the discussion remains unresolved.
Participants have not reached a consensus on the specific methodologies for calculating pressure drops or the acceptable values for the "p/D" ratio in triangular lattice configurations within steam generators. There are also unresolved assumptions regarding the applicability of shared resources to the specific problems discussed.
Thank you very much for such a kind response,Michal Kovac said:Hi, you wrote about pressure drop in fuel assemblies. But you have to specify, whether you mean pressurized water reactors (single phase flow) or boiling water reactors (two-phase flow).
In general, total fuel assembly pressure drop is formed by fuel bundle frictional drop (dependent on relative roughness of fuel rods, reynolds number, hydraulic diameter etc.) and other pressure drops of structural elements (top and bottom nozzle, spacing grids or mixing grids).
In general, it is not so simple to calculate pressure drops in fuel assemblies (especially the spacing grids) and it belongs to key know-how of certain fuel manufacturer. Mostly, pressure drops are measured in experimental hydraulic loops, rather than calculated.
If you want to know more, specify your problem. Here are some valuable sources:
Frictional losses - single phase
Pressure drop - two-phase