Experimental study of the static pressure and the wall shear distributions in a seven-rod bundle with helical wire wrap spacers

The fluid flow hydrodynamic behaviour in a seven-rod bundle with helical wire wrap spacers was simulated. Several measurements were performed by varying the axial and angular position of the wire wrap lead, for different Reynolds numbers. It was observed the existence of low pressure zones on the surface of the rods and that the wall shear stress distributions, made dimensionless when divided by its average value, is independent of the Reynolds number. It was further observed abrupt variations in the static pressure and wall shear stress distributions which should be taken into account in the thermohydraulic design due to the possibility of occurrence of cavitations bubbles in the coolant. 13 refs, 63 figs, 29 tabs