The blockage model of Upgraded Cheng and Todreas correlation for pressure drop in hexagonal wire-wrapped rod bundles

A model to predict the pressure drops in a hexagonal wire-wrapped rod bundle with blockage is developed. The model is based on the Upgraded Cheng and Todreas Detailed (UCTD) correlation. Two series of experiments from Texas A & M University (TAMU) and Karlsruhe Institute of Technology (KIT) are used for calibration and validation. The UCTD correlation for drag and swirl forces are modified to account the presence of the blockage. The characteristic velocity of the Reynolds number is revised. The pressure drop is well predicted in the turbulent flow regime with a mean error less than 3%. The friction factor of transition flow regime is an interpolation between laminar and turbulent. Due to the lack of data in laminar flow regime, the mean error in the transition regime is higher than 5%. Overall, the mean errors of the two validation cases are 2.5% and-0.6%, and the root mean square (RMS) errors are 3.2% and 7.2%. To improve the accuracy and extend the ability to predict complex blockage conditions such as blocked thickness or porosity, a variety and an amount of experimental data are needed.