Heat transfer and ice formations deposited upon cold tube bundles immersed in flowing water—I. Convection analysis

Abstract

A staggered and an in-line tube bank configuration were subjected to a crossflow of water. Internal tube subcooling (< 0°C) resulted in gradual ice deposits to occur on the outside of the tubes; this moving ice-water interface was then allowed to stabilize. Testing focused on the low to moderate Reynolds number range ( Re = 100–1300) and ice-water cooling temperature ratios Θ between 0.5 and 8. Photographic documentation was followed by a finite element analysis (FEA) of each ice shape. Steady-state results included (1) the total rate of energy exchange Q between the tubes and the crossflow, (2) the total ice volume V which eventually coats the tubes, and (3) the row-to-row variation of both Q and V within the tube banks. Steady-state ice shape contours observed fell into three different categories: (1) thin, almost concentric ice formations (high Reynolds and/or low Θ values); (2) elongated ice shapes with a dominant axis either parallel or perpendicular to the crossflow; and (3) large ice deposits connecting adjacent tubes and leading to ice bridging of varying extent (low Reynolds and/or high Θ values). The ice formations will, when compared to non-icing tube banks at similar Reynolds numbers, either increase or decrease the heat transfer rates depending upon the volume of ice accumulated. Correlations for Nusselt number and the total amount of ice volume produced on both staggered and in-line tube banks with ice formations at steady state were developed.