Investigation of phase change in a spiral-fin heat exchanger

In this study the effect of a spiral fin on the melting process of a phase change material in a heat exchanger is investigated. Water as the heat transfer fluid enters the tube at 348 K and the phase change material, RT50, the melting temperature of which is in the range of 318 K to 324 K, fills the space between the tube and the shell. This study focuses on the effect of geometrical parameters of the fin including the fin thickness and fin pitch on the melting process. In addition, the effect of changing the heat exchanger angle with respect to the horizontal is examined. Results indicate that fin shape is a critical parameter in every modification. In fact, for constant fin thickness, provided the fin pitch varies from 10 mm to 20 mm, due to 58% increase in fin height, the melting time reduces about 35%. Moreover, considering constant fin pitch, when the fin thickness increases from 1.5 mm to 2.5 mm, because of the 28% reduction of fin height, the melting time increases 59%. Also, an increase in the angle of the heat exchanger from zero to 90°, affects the melting process considerably.