Pressure Drop Correlations for Fuel Element Spacers

Pressure Drop Characteristics in Tight-Lattice Bundles for Reduced-Moderation Water Reactors

“…Here, V is the velocity, v the kinetic viscosity. Figure 2 displays that K is strongly dependent on the ratio of flow areas A 2 /A 1 and the length of a spacer, as described by Rehme (8) and Okubo, et al (10) When A 2 /A 1 is between 0.7 and 0.8, K ranges from 0.5 to 1.0. The K value is usually adopted in the pressure loss calculation of the reactor core with multi-rod fuel bundles.…”

“…A simple evaluation method for the spacer loss is therefore useful for the design of the reactor cores with the multi-rod bundles. Rehme (8) investigated the pressure loss at the several types of spacers experimentally. He indicated that the loss coefficient for the grid-type spacers is dependent on the relative plugging of a flow cross section, whereas the pressure loss coefficient for the wire-wrapped rod bundle is dependent on the lead of wire wraps.…”

Development and Validation of Coupled Dynamics Code 'Trikin' for Vver Reactors

“…The spacer pressure drop can be comparable in magnitude to the friction along the bare rod bundle. Rehme [7] has undertaken several studies to determine the pressure drop across spacers with different geometries. After detailed experiments, Rehme devised a list of pressure drop coefficients across the spacers with different geometries and with different arrangements.…”

A Pressure Drop Model for Spacer Grids with and without Flow Mixing Vanes.

“…The drag force on the grid region is divided into four parts: form drag on the grid, frictional drag on the grid, frictional drag on t,he rod, and form drag on the mixing vanc: F = FEE + F::: + FE: + FEZ"'. (1) A grid loss coefficient is defined, for practical use, on the free flow area of bare rod region A0 as follws: But actually t,he pressure drop at grid region may be governed by the flow velocity at grid. In the present model each pressure drop A P is determined on the average velocity at grid region Us, and formulated by introducing the available form or frictional loss coefficienh from t,he open literatures.…”