Experimental evaluation of gas heating and flow modification effects by plasma actuator in forced-convection heat transfer

• Plasma actuators (PAs) boost forced convection heat transfer but also induce gas heating. • A modified Newton's law of cooling accounts for both flow acceleration and gas heating by PAs. • Novel experimental framework decouples and quantify PA-driven flow acceleration and heating contributions. • Two key nondimensional parameters characterize these two effects. • The research outcome enables prediction of PA-enhanced heat transfer performance. Dielectric-Barrier-Discharge Plasma Actuators (DBDPAs) are promising active flow control devices with the potential to significantly enhance convective heat transfer. However, their influence is twofold: while they accelerate boundary layer flow, they also introduce gas heating due to plasma discharge - an effect that can complicateheat transfer performance. This study aims to establish a novel experimental method to decouple and evaluate theese two competeting effects - heat transfer enhancement and the gas heating within a forced-convection heat transfer. By interpreting their contributions as variations in the Nusselt number and freestream temperature, respectively, within Newton’s law of cooling, we conduct controlled wind tunnel experiments using a wall-mounted DBDPA. To generalze the findings, we introduce two nondimensional parameters representing the actuator's momentum input and the gas heating energy. Our results show that both the Nusselt numbers and the freestream temperatures scale onsistently with theese nondimensional parameters across a arange of experimental conditions. These relationships offer a predictive foundation for assessing DBDPA-induced heat transfer enhancement and gas heating effects in broader thermal-fluid applications.