CFD simulation of flow and heat transfer characteristics in a 5×5 fuel rod bundles with spacer grids of advanced PWR

Experimental Study of Pressure Loss in a 5 × 5–Rod Bundle With the Mixing Vane Spacer Grid

“…The axial pressure loss contains the wall friction upstream of the spacer grid, the spacer grid resistance, and the wall friction downstream of the spacer grid. The trends of sharp decreasing of axial pressure at the spacer grid region and slight increasing downstream of the spacer grid have also been presented in studies (Caraghiaur et al, 2009;In et al, 2015;Han et al, 2018;Wu et al, 2017;Xiong et al, 2018;Sibel Tas-Koehler et al, 2020;Wang et al, 2020). As explained (Wu et al, 2017), the rapid decrease in axial pressure in the height of the spacer grid is caused by the local resistance of the spacer grid, especially the form drag on the straps and mixing vanes (Chun and Oh, 1998).…”

“…The axial pressure upstream of the spacer grid gradually decreases due to the wall friction of the rod bundle. But the axial pressure suddenly jumps down just before the spacer grid, and in the region of the spacer grid, the axial pressure decreases sharply (Wang et al, 2020). Downstream of the spacer grid, the axial pressure increases slightly just near the spacer grid, and then it decreases slowly.…”

“…Both the local geometry details and the influence of the neighboring sub-channels play an important role in the pressure distribution. Many researchers predicted the axial pressure loss in the rod bundle with the spacer grid using CFD simulations Cheng et al, 2017;Wu et al, 2017;Han et al, 2018;In et al, 2015;Xiong et al, 2018;Sibel Tas-Koehler et al, 2020;Wang et al, 2020). The axial pressure upstream of the spacer grid gradually decreases due to the wall friction of the rod bundle.…”