.TRANSFORM.Fluid.FittingsAndResistances.SpacerGrid .TRANSFORM.Fluid.FittingsAndResistances.SpacerGridPressure loss of a rod-bundle spacer grid using the Rehme (1973) modified drag-coefficient method (K_spacerGrid_Rehme):
dp = K*m_flow^2/(2*rho*A_bundle^2),K = C_v(Re)·ε²
referenced to the undisturbed bundle velocity head, where
epsilon is the blockage ratio (spacer projected
frontal area / bundle flow area, typically 0.15–0.5),
crossArea is the bundle free-flow area and
dimension is the bundle hydraulic diameter (used for
the Reynolds number). The modified drag coefficient
C_v(Re) uses the Cigarini/Schikorr semi-empirical fit
of Rehme's chart. A common dominant contributor to
core/fuel-assembly axial pressure drop; stack several in series
along a bundle. Flow reversal supported.
Rehme, K. Pressure Drop Correlations for Fuel Element Spacers, Nuclear Technology 17 (1973) 15–23; Schikorr et al., Nucl. Eng. Des. 240 (2010) 1830–1842.