The Influence of Branched Annular Fins on the Performance of Phase Change Heat Exchangers

The shell-and-tube phase change heat accumulator has extensive application in industrial production due to its small temperature change and high heat storage density. A novel structure with annular fin branches was designed to enhance the shell-and-tube phase change heat accumulator’s heat transfer performance. The phase change heat transfer performance in the shell-and-tube heat accumulator with branch annular fins was studied by using FLUENT software. By analyzing the evolution of the PCM liquid phase, the distribution of temperature and velocity, the variation of melting rate, and the uniformity of the temperature distribution and so on, the heat exchange property of the branch annular fin during melting was analyzed. The new type structure of annular fin with branches preserves the radial heat transfer depth of ordinary annular fins, while increasing the longitudinal heat transfer depth and heat transfer area. Compared with heat accumulator with ordinary annular fins, the time that the PCM completes melting is shortened by 27.13%, the uniformity of melting rate is increased by 34.72% and the uniformity of temperature distribution is increased by 1.55%. Furthermore, the heat transfer performance of phase change heat accumulator with the shell-and-tube structure can be significantly enhanced by shortening the main fin’s length or increasing the branch angle of the main fins. The study result of this paper has great guiding significance for the research and development of the shell-and-tube heat accumulator with fins.