3D-printed converging wick flow condensers for low surface-tension fluids: Modeling and experiment

State-of-the-art enhanced condensation techniques demonstrate inferior filmwise thermal performance and long-term reliability in the case of extremely wetting low surface tension fluids. To address this issue, the converging wick structure concept is proposed for enhanced flow condensation of low surface-tension fluids. The converging wick structure offers promising features, including strategic distribution of the solid-fluid interfacial area along the condenser length to account for the variations in the local vapor quality. It also considers a converging profile to compensate for the reduced convective effects due to the vapor-to-liquid transition. Additionally, the 3D-printed copper wick structures are mechanically robust and in their intrinsic state (i.e., no coating or liquid infusion), thereby offering long-term reliability. A semi-analytical wick flow condensation model for low surface-tension fluids is also developed to predict the thermal performance of the proposed converging wick flow condenser and offer guidelines for future optimization efforts. The wick flow condenser is 3D-printed with GRCop-42, a high-thermal-conductivity copper alloy. The experimental and modeling results show that the proposed converging wick flow condenser offers a higher overall condensation performance compared with its plain condenser counterpart. Insights gained from the current study offer new pathways to engineer compact and durable 3D-printed wick flow condensers with promising heat transfer characteristics for low surface-tension fluids.