Page 356 - Thermal Hydraulics Aspects of Liquid Metal Cooled Nuclear Reactors

322 Thermal Hydraulics Aspects of Liquid Metal Cooled Nuclear Reactors

Fig. 6.2.3.7 Validation of RANS using 19-pin data from KALLA experiments.

simulations, typically, the mesh density in the centers of the subchannels is reduced,
the wire shape is simplified, and the well-resolved boundary layer has been omitted
(see Fig. 6.2.3.8). They show that this leads to a reduction of accuracy for temperature
predictions of about 20% compared with the well-resolved model (the accuracy of
velocity predictions is much better).
Fig. 6.2.3.9 shows the result of a simulation employing the reduced resolution tech-
nique for a complete 127-pin MYRRHA fuel assembly including headers and footers.
This simulation provided the design team with important information about the pres-
sure drop to be expected (see, e.g., Kennedy et al., 2015) and the maximum clad