Dimensionless analysis of thermal contact resistance impact on heat transfer performance of rectangular fins applied in nuclear plant

This work aims to investigate the effects of welded Thermal Contact Resistance (TCR) on heat transfer for rectangular fins applied in passive nuclear plant. The dimensionless equations are established to describe fin efficiency and overall surface efficiency when subjected to TCR. An experimental set-up using a hot box are developed, and 18 experiments of fins with bilateral fillet welding (BFW) and unilateral penetration welding (UPW) are performed to obtain the range of TCR. Results show that the TCR values are about 0.006 and 0.002 (m2 K)/W for BFW and UPW, respectively. Dimensionless fin efficiency rif' and overall surface efficiency ri0' are governed by several dimensionless parameters that group thermal resistance, important material properties, and geometric parameters of the fin or substrate. TCR has a remarkable effect in the range of 10-4<Bi < 10-2, and the adverse effect of TCR on rif' and ri0' can be weakened by changing the geometric dimensions or material properties in a certain range.