Izvestiya vuzov. Yadernaya Energetika

The peer-reviewed scientific and technology journal. ISSN: 0204-3327

Fluid flow and heat transfer in fuel rods assembly with modified spacer grids

10/23/2015 2015 - #03 Thermal physics and thermal hydraulics

Krapivtsev V.G. Markov P.V. Solonin V.I.

DOI: https://doi.org/10.26583/npe.2015.3.10

UDC: 621.039.517

The paper considers the fluid flow and heat transfer in fuel rods assembly with modified spacer grids for light water nuclear reactors. Modified spacer grids are designed by «Mashinostroitel’nyj Zavod» (Electrostal’, Russia). Cells of modified spacer grids rotate stream by corrugations, angled to the axis of cells. It’s possible to generate different secondary flow downstream the grids by compilation of grids by cells with different direction of rotation (clockwise or counterclockwise). Two types of modified spacer grids are considered: spacer grid of first type consist of similar cells and generate secondary flow like «rotation around rod»; spacer grid of second type consist of different cells and generate horizontal secondary flow between rows of rods. Investigation was performed by methods of computational fluid dynamics. Results of numerical simulations were validated with data of physical experiments. The mechanisms of secondary flows generation are described. The values of pressure drop coefficient of modified spacer grids are given. The influence of flow conditions (Reynolds number) on values of pressure drop coefficient is described. The analysis of the intensification of coolant’s mixing by modified spacer grids with different boundary conditions is described too.The conclusion about possibility of application modified spacer grids to decrease temperature nonuniformity in coolant flow due to generation of secondary flow had been done.

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spacer grid nuclear reactor core fuel rod intensification of coolant’s mixing secondary flows computational fluid dynamics