Numerical study of melted PCM inside a horizontal annulus with threads in a three-dimensional model

Abstract

This paper presents a numerical investigation of the melting process of a phase change material (PCM) in a tube and shell geometry. Since previous literature mainly focused on the 2-D model, a 3-D model is established in the present work with CFD software to take the velocity and heat transfer along the axial direction into account. In order to enhance the tube's heat transfer performance, two types of threads with different geometry parameters are introduced. The inner cylinder is assumed to be at constant temperature and the outer cylinder insulated. Temperature contours and streamlines are obtained to cast light on the effect of the threads. The predicted result shows all the threads can accelerate the melting process in the top region where natural convection is dominant, and the magnitude of the enhancement is determined by geometry parameters to some extent. However, none of the applied threads has improved the melting rate at the bottom region where heat conduction is dominant.