Three-dimensional flow structure in a narrow gap of the model of a fuel assembly peripheral cell: tomographic velocity measurements with high temporal resolution
M.V. Shestakov
Kutateladze Institute of Thermophysics SB RAS, Novosibirsk, Russia
Keywords: experiment, complex-shaped channels, narrow gap, TR-Tomo PIV method
Abstract
The three-dimensional structure of the flow in narrow gaps between fuel assembly (FA) rods has a decisive influence on the heat and mass transfer coefficients, which, in turn, determine the FA performance. In this work, instantaneous three-dimensional velocity fields were measured for the first time in a model of a FA peripheral cell using the Tomographic PIV method with high temporal resolution. The experiments were performed at Reynolds number Re = 2100. The study, conducted using the TR-Tomo PIV method, allowed characterization of the three-dimensional structure and dynamics of the flow in a narrow gap of a FA peripheral cell. Based on the obtained data, the components of the vorticity vector in the flow volume were calculated. It is shown that the key mechanisms, responsible for generation of extreme values of longitudinal vorticity, are transverse flow oscillations. These oscillations are quasi-periodic in nature (Sh = 0.091) and alternate with stabilization phases, which are characterized by a straight-through flow.
|
