Optimizing Heat Exchanger Efficiency through Enhanced Surface Textures and Water Film Cooling*

Water cooling is more effective at dissipating heat than air convection. However, the complex geometry of heat exchangers can hinder complete surface wetting, leading to dry areas and reduced cooling efficiency. To address this, enhanced fins with varying textures are necessary to maintain high heat transfer. This study focuses on the cooling effect of a water film.

An experimental setup was designed where an electric resistance heats a copper plate, and water coming from a syringe pump cools it. Air convection is forced through an air duct. As the plate's temperature remains below the boiling point, the evaporation is controlled by the air flow. Various surface textures were tested, including hydrophilic, hydrophobic, and porous media, while varying the heat flux and water flow rate.

A series of experiment has been carried out showing that a tradeoff occurs between the energy moved away by the flow and consumed by the phase change. For instance, a porous media helps in high wetted surface and water retention therefore increasing the evaporation effect and reducing water consumption. Various parameters controlled in our setup are thoroughly analyzed to identify the optimal regime for efficient cooling.