Comparative thermal analysis of multiple topology-optimized fins under gravity

Fins generated through topology optimization can improve heat transfer paths and enhance the thermal efficiency of latent heat storage units. However, although a single design domain can produce diverse fin configurations, the effect of design domain selection on the resulting heat transfer paths has received limited attention. This study compares different topology schemes under the same geometric and operating conditions while considering gravity direction. It also examines how fin volume ratio and the corresponding area to volume ratio affect the overall thermal performance. The results show that parallel gravity placement reduces the total melting and solidification time by 4.87% compared with vertical gravity placement. Among the four schemes, the multi-tube topology scheme performs best. Its total cycle time is 24.22%, 21.22%, and 41.26% shorter than those of the horizontal, vertical, and eccentric topology schemes, respectively. Its melting to solidification time ratio reaches 0.58, indicating good coordination between the melting and solidification processes. Within the fin volume ratio range of 7.5% to 12.5%, complete melting time does not decrease monotonically as the fin surface area increases. Instead, an inflection point appears, and changes in the area to volume ratio have a marked effect on heat transfer efficiency. Within this range, a 10% fin volume ratio avoids excessive flow blockage and prevents the efficiency loss associated with a low area to volume ratio.