An experimental study and assessment of existing friction factor correlations for wire-wrapped fuel assemblies

The main objective of the present study is to perform a comparative study o f five existing correlations that have been selected and identify the best performing correlations in the subchannel pressure drop analysis of a wire- wrapped fuel assembly by means of directly comparing with experimental data obtained in the present work. For this purpose, a series of water experime nts have been performed using a helical wire-wrapped 19-pin fuel assembly f or various combinations of test parameters, Four different test sections th at have different pitch to rod diameter ratios (P/D) and wire lead length t o rod diameter ratios (H/D) have been fabricated. A series of pressure drop measurements were made to obtain friction factors for these four test sect ions. A total of 293 data were obtained and the present along with existing data are used in the present comparative study of existing correlations. T he results of this study show that both the original and the simplified Che ng and Todreas correlations give the best agreement with experimental data for all flow regions. (C) 2001 Published by Elsevier Science Ltd.